Thanks Mark 😉Glad I could help. Edit: tip for you reloaders that reloaders should already know, only reload one thing at a time. Only ever have one powder opened in front of you at a time. Then you will not use the wrong powder. Stay safe!
Depends a little on how you mean that. One type of ammo at a time, yes. Reloading in batches and work through stages is very reliable. If you have 50 rounds on the table with powder waiting for the seating, that’s a great time to visually check that they all look like the same fill point. Anything seeming high or low, dump and redo.
Yes! Been a long time since I did any reloading, being in UK-land. But N310 was a blast from the past because that was my favorite pistol powder, and speculated a while back that the problem was using that instead of a rifle powder. Can't remember what powder I used for rifle loads, but I do remember it being a different vendor so the packaging was completely different. Less risk of grabbing the wrong blue bottle. I was also curious about energy density given issues around powder vs case volume to develop the pressures involved. I guess that would be a useful data point for wildcat developers looking to min/max cases to pressure curves, without encountering RED (Rapid Energetic Disassembly) issues.
I actually am undefeated at my local high-school for launching a melon. Most students in physics class built trebuchet, catapult, slingshot etc,. I opted for basically a giant potatoe gun. When I was dumb enough to shoulder fire it using a BBQ lighter tied to a redementary grip and a chamber filled with oxy-ecetylene, using cereal bowls bolted together for a wad, I nearly broke my arm. The melon flew to the heavens and I never found it. When the competition at school arrived it was made to be a cannon and was mounted at 45 degrees and aimed off into the empty lot. We lost site of the fruity projectile and the school shut the show down pretty quick. To this day I have a plaque as the record holder which reads "distance unknown"
How far away from the cannon were you made to stand? I am assuming there was teacher supervision at the time of the event? I expect many people have had some experience with potato guns growing up, in a rural environment at least. Going as large as a watermelon had not crossed anyone's mind that the cannon could just become a large pipe bomb?
Hi Mark. It is OK to hate being wrong, and even better to still be able to learn from it. That is why I am here, to learn from everyone who knows better than I do about the topic. Thanks for not running from this one, it is fascinating! Cheers from Texas.
Sometimes it's good to be wrong and to be challenged. As long as you're not pushing lies as fact (or opinions as fact), then it shouldn't be a big deal, but more of a learning experience. We're all ignorant about some (many/most) things... and people would be shocked to learn that so much of what they Know to be true is actually lies. Even the smartest people in the world know almost nothing at all (when what they know is compared to what they don't know).
@@deucedeuce1572 And some of the smartest people in the world know things that aren't true and may never learn because they refuse to see others' viewpoints and learn that what they believed all their life is actually false.
@@fettmaneiii4439 What if his designs had nothing to do with it and that ANY 50BMG rifle would have exploded with the same round? Do you know they wouldn't? (and is he not innocent until proven guilty?)
Hi Mark, you mentioned a "couple of fail safes" that no one seems to have commented on. It surprised me the number of people who commented in various videos concerning this incident of the "dangerous lugs" that flew off and nearly killed Scott, IMHO for what its worth these "dangerous lugs" actually saved Scott's life! If you hadn't added them to your design to ensure complete closure of the breech then that end cap would have come straight back and there would have been a very red wet hole in the atmosphere where Scott's head should have been. Cheers from the UK
@@Lofi.z34 Mark discussed reinforcing the lugs in a previous video. You eventually get diminishing returns. By trying to overengineer and reinforce the lugs they will be propelled at a greater speed with more energy when they do fail thus inflicting more harm on the user. I think people are putting to much emphasis on those lugs as a protective measure when their real purpose is to act as a way to ensure the screw cap is closed. If the gun fails spectacularly enough to where the screw cap comes flying back then your already screwed no matter how those lugs are reinforced.
@@Launchpad_McQuack_Is_A_Chad I'm not sure I buy his argument there, there is definitely room to reinforce, or reprofile them before that becomes an issue. If you look at the rifle from the side, the "lug" seems to be formed by removing a section behind it, which then rises up again, and I don't see why it's necessary to do that at all, just have the top edge be uninterupted, if you do that, and the rifle still fails, you're dead anyway. Theres a story about the introduction of metal helmets in the military, at first people thought that they caused brain injuries, when infact without the helmet, the person would be dead instead. It's kind of like that. "If the gun fails spectacularly enough to where the screw cap comes flying back then your already screwed no matter how those lugs are reinforced." Correct, at some point you're screwed no matter what, but that is NOT a good reason to not introduce improvements. The problem is now that any change to the design at this point would be a legal minefield, it could be viewed as an admission that there was something wrong with it, and cause legal action to be taken when it wouldn't otherwise be.
@@LeoH3L1 The round that blew the gun was well in excess of seven times that of what a slap round should be loaded for. Take a look at Scott's channel, he had previously been firing slap rounds for a good 3 years at least with many of those being from the RN-50. The round that blew the gun has been shown to be able to blow several types of .50 caliber rifles. An incident like this is not a cause to try to make the gun fail safely for something well over 5x what the gun is rated to handle. The gun's failure point is already above and beyond what is required. You don't wear a plate rated to stop up to .308 and then demand it be improved when it doesn't stop a .50 so why demand that of a gun when it is pushed beyond its rating?
@@fettmaneiii4439 Did you watch the video? The safety features were not at fault, the fault was traced to pistol cartridge powder being used in what should have been a rifle powder powered cartridge. MASSIVE difference. If you follow Kentucky Ballistics you'll see Scott, the guy who had the RN50 fail on him and damned near kill him testing various weapons to failure. They all handle correct loads as they should, but when loaded with excessive powder charges they ALL fail. Serbu's designs are not in question here. It was a secondary market issue, with someone using a powder vastly overrated for the intended purpose. THAT'S why the rifle exploded. It had nothing to do with any safety features incorporated into Mark's design.
@@fettmaneiii4439 It's a little hard to make something fail safely when it's over its design capacity by an order of magnitude. There is no problem putting one liter of water in a one-liter bottle. Putting 10 liters of water in that same one-liter bottle poses some considerable problems.
@@fettmaneiii4439 To me it sounds like he's exploring failsafe mechanisms/geometry, and that it will be part of the next video. And of course it should be made to blow up and break in a safer manner if possible. I agree with that. But mate, this was a freak round. I'd be surprised if the majority of experimental weapons don't lack the ability to fail safely when subjected to so much force, with bits and shards flying at the shooter and everyone beside them.
My BFG50 arrived a few days ago... it's because of how you handled this situation (and it's a beautiful gun) that I got it. No one expects perfection, but we want honesty and accountability. Sig on the other hand is a great example of the opposite.
If you examine a few facts, it becomes OBVIOUS this would be the case. First, one needs an efficient burn in a far more abbreviated space. So, our pistol powder (which has reasonably equivalent energy density to a similarly compounded rifle powder) has to burn faster by design. Usually, this is done by varying size of individual "pieces" (grains is the usual nomenclature, but it's also the weight measurement unit in reloading, so let's call it "pieces" for clarity). "Traditional" rifle powders (like the IMR varieties) use tiny little cylinders as the "pieces" of powder. They vary from sewing needle to standard pencil lead diameters, with lengths between 1/10 and 1/4 inch. Pistol powders tend to be the smallest cylindrical sizes (very short length compared to diameter) or flakes. More modern stuff tends to be rough spheroids (ball powders) that use coating and additives to control burn rates. Ok, burn volume is a function of surface area. Our chunky cylinder rifle powder "piece" rapidly loses surface area as it burns. Like a log in a fireplace, length shortens, diameter falls as it burns. Our tiny short skinny cylinder pistol powder burns more like a twig, same burn characteristics, but it gets consumed far faster than a log. Flakes burn like a sheet of paper tossed in the fireplace, foomp gone, muy rapido. Smokeless powder has another whacky burn characteristic related to confinement. A tablespoon of powder dumped in an ashtray and lit with a match just kinda gives a slow fizzy greasy burn, it might take 2 seconds to burn out. Same in a proper sized case behind the right projectile, it burns several hundred times faster, and the higher the pressure the faster it burns. Ok, so in the graphs shown we see an equivalent energy, the rifle powder is being subjected its natural environment. The pistol powder, however, assuming something like bullseye or hp38, is intended for mild pressure light target loads. It's already burning away far faster than the IMR type powder, but it's rapidly in an environment where pressure soars to 4 or 5 times it's normal conditions, causing it to burn even faster, creating even more pressure, causing faster burn, more pressure, ad infinitum. Same potential energy, with a burn completion in 1/10 the time, equals equivalently higher pressure. The graphs and the realities of nitrocellulose burning in confinement agree 100%, though my bet is the loader building those SLAP rounds was using ball powder, had a hopper run empty, and grabbed one full of a pistol ball powder that "looked the same". That would put the final pressure somewhat lower than bullseye, but still FAR in excess of "mil-spec".
@@ludditeneaderthal Wow, thanks for the master class in the burn rate of different powders! Broken down the way you did, that makes a lot more sense about the differing burn rates of pistol vs rifle powders. Like I said, not a reloader, but I follow along with the explanation of the physics of gas pressure in a confined cylinder.(Here being the case itself.) Thanks for the lesson!
For example in the current Ukraine war. If the fleeing Russians had had available some sabotaged ammo they could have planted a few rounds. They weren't planning to fail, though, and as a result wouldn't have any pre-sabotaged ammo. Theres another issue, it's really bad to have that around.
@@heatheryllanes6925 yeah it's actually a really bad thing to make. Your own soldiers may accidentally load it or unrelated innocent people may buy it.
@@GeraldMMonroe I'd be surprised if they are not doing it. Spiked rounds are not only for when you retreat, they are also for injecting into your enemy's supply chain. The Russian army must have a stash of it somewhere and I wouldn't put it past them to do such a thing
N310 is the fastest pistol powder in the Vihtavuori line, only the old blank powder is faster. We use it to make light subsonic loads and low recoil training loads for 7.62x53r The scale from ok pressure and way too much is really small, and to even thinking about having a full case let alone 50bmg case full of that stuff is very scary!
Hi MJ .. Norma R1, is the fastest burning powder then VV N310 then VV N 320 that is equal Bullseye..Personally I would not recommend using such a fast burning pistol powder in reduced rifle loads it is not required, you are asking for trouble ..Much safer to use the slower burning rated pistol powders you will get the same results and have more safety margins..good shooting..
@@ianbrown1058 He did say fastest in the Vihtavuori line, not fastest overall. And I somewhat disagree with you on choice of powder for subsonic rifle loads, at least for use in European countries where suppressors are common and bolt action rifles are the norm. We don't have to care about gas port pressure, since we are not trying to cycle a semiauto. And the fastest powders allow for lower muzzle pressure, thus reduced noise, at the same muzzle velocity. Furthermore, in my experience loading subsonic .308, the fastest most easily ignited powders have the most consistent burns and velocities out of large cases. A typical subsonic rifle load with VV N310 and heavy bullets runs such low pressure that even a double load would be well within SAAMI max. Plenty of safety margin, it doesn't even expand the brass. And it gives good accuracy. So why bother with slower, less consistent powders unless you're trying to cycle a gas operated rifle?
So how does this get put into a 50 bmg round and sold to a random civilian? Is it as nefarious as it sounds to me? Is it a "spiked" round or an accident(i dont see how)?
Thanks so much for cutting to the chase and saying what happened right at the beginning of the video, so I could focus on the rest of the video knowing where we were heading.
Mark, that graph indicates that you should start making bench rifles in 30/40 caliber that can withstand 300,000 psi and shoot @ 6000 ft/s at 5 miles or so.
I built a test bed .177 cal BB gun when I was in tech school for machining, I ended up building a rifle that shot .177 steel BB's at a max velocity of just a tad over 5000 FPS, I could never get anything over 5100 FPS no matter how much more powder I loaded, it's about the peak limit of velocity with smokeless powder. I was putting an average of 6 grains, up to a max of 9 grains of .22 LR powder (about the fastest burning powder in existence) into the chamber and igniting it with 209 Winchester shotgun primers, I do believe I was exceeding 200k PSI of chamber pressure, since the chamber walls eventually began to bulge which is saying something, the ID of the chamber was only .240" and the OD was 1.500" and made of heat treated chrome-moly steel, as thick as many rifles firing full-size cartridges, yet it was starting to balloon out. The primers were immensely deformed after each shot, and it would put BB's through 3/16" thick steel plate lol. Moral of the story, at a certain point you're only putting energy into destroying your gun, in something like what I built where the powder load weighs over 1.5 times more than the projectile, there is no benefit. It took about three shots before the rifling disappeared, and it was on the tenth shot that the chamber started bulging out, I would have had to make the chamber two inches thick, maybe bigger, to be able to handle that kind of pressure and I would _still_ be swapping out barrels every dozen shots lol. It's cool and all but not in the slightest bit practical.
@@TheExplosiveGuy A BB-gun using powder as a propellant? That's more like BS-gun. A BB-gun is always some kind of air gun. While the name of the gun comes from what it shoots, the shooting mechanism is integral part of the definition and can never be an explosive propellant. Otherwise nearly any gun could be referred to as BB-gun as most are able to shoot some kind BBs excluding rifled and choked barrels. What you made is not a BB-gun but just a smooth bore rifle (a stupid misnomer, but I'll go with it) that shoots unconventional ammo for a rifle.
Seeing all the videos you’ve made about this incident and how much you’ve worked to understand why this went down has made me a life long supporter and hopefully future owner of Serbu firearms. Other companies could learn a thing or two from your dedication
Even the proper rifle powder can become dangerous if the grains are broken....being their size and coating is one of the main controls to the burning rate. Degraded powder can also greatly increase in burn rate and can be very dangerous...and, of course if someone used a completely unsuitable powder is the other way bad things happen. One other phenomenon that has happened is a partial fill charge of very fast powder basically detonating. Proper loading means the charge fills most of the case so its' position at the instant of ignition forces the fire to work its' way progressively through the charge. There have been many reduced 'target' loads blow up guns where these very light charges need the muzzle to be raised and rifle tapped before firing to settle all the powder back against the primer. If this isn't done the powder can stick all around the case and then the primer flash ignites it all instantly which causes a huge over-pressure. I had a 45 Colt detonate once and instead of the normal 'pop' (this was with WW231) it went BOOM! with a bright muzzle flash. The normal rounds didn't make any flash so something bad happened. This was NOT a double-charge because I tried doing that with a 454 Casull and it wasn't near what had happened with the light charge. I doubt that's what happened to Scott's rifle, but just wanted to caution people to always use a powder density fitting the case.
@@diychad7268 No, that's the phrase used. Degraded, when talking ammunition, doesn't mean it doesn't work, it generally means it's going to burn a lot faster then it is supposed to. It's the same mechanism that can make a stable explosive unstable after storing for too long or improperly.
I've heard pistol powder in rifles = boom for a long time but having not gotten into reloading yet I never knew the math on just HOW bad it was... Those numbers are insane. You did a really good job breaking it down, thanks Mark.
Woah, I'm not a gun guy. I'm just a strong supporter of our rights to have them. I had no idea there was a difference in how quickly powder burns. The explanation made perfect sense. Thanks for the educational video.
That's the reason there are so many different brands. Different burn rates and some are made to take up more space to give you a slightly larger margin of error when it comes to charge weights. I WISH there was only one powder! lol
All the way down to tempurature ranges that they are stable in. I forget but every so many degrees of increase in temp will increase the velocity/pressure too. Causing shots to climb on paper if you shoot to fast.
Then there's also the whole thing about modern smokeless gunpowder versus old blackpowder. Though smokeless powder charges of equivalent pressures can be loaded for guns rated for blackpowder (and this was done with commercial ammunition), the margins for error are pretty slim, and it's dangerous to experiment with, so the general rule of thumb is to just never put smokeless gunpowders in old blackpowder guns. If you've ever seen a musket someone has tried to use smokeless powder in, the entire barrel will typically have violently twisted open and it looks like a big jagged metallic banana peel. It's important to be mindful of what powders you are using and for what when you're loading your own ammunition (or shooting old muzzle loaders). There are rifles chambered for pistol cartridges, but replacing the powder in a rifle cartridge with an equivalent volume of powder for a pistol turns it into a bomb.
But ,why was only one round loaded with pistol powder? If you're making counterfeit ammo ,why would you load all the other rounds correctly and then just load one with pistol powder?? Definitely the Government
@@j.robertsergertson4513 How can you be sure only one round was loaded with pistol powder? For obvious reasons, no further shooting of the suspect rounds was done after Scott's near-death experience, so we don't know how many other rounds were similarly dangerous. We also don't know how many rounds were loaded in total. For all we know the person could have loaded hundreds or even thousands of those rounds, which could have been sold to any number of buyers besides Scott. If pistol powder were knowingly or unknowingly mixed with or substituted for rifle powder during part of the loading process and then the loaded rounds stored loose in a large container until they were ready to be packaged for sale, any particular package of rounds could have a random mix of rounds of varying danger levels. Also, if the person who loaded the rounds designed the loads with pistol powder in mind, there's always the possibility that the load called for a small enough powder charge that there was room for an accidental double-charge. This could explain why several of the cartridges showed warning signs of excessive pressure, despite not blowing up the gun.
@@j.robertsergertson4513 If you go back to Kentucky Ballistics' video originally detailing his original RN-50 detonating and his injuries, Scott showed footage of his other SLAP round shots into his fire hydrant target...and they were acting wonky (shots not penetrating or veering off). So it's possible multiple rounds in the lot he purchased were bubba'd with pistol powder but with lower potions...or some dingleberry "cut" rifle propellant powder with pistol powder and the round that nearly killed Scott was one where it was reloaded with just pistol powder or a mix where pistol powder was the main propellant type used.
Thank you for chasing this answer until the very end. It gives a better understanding of the "how" and "why" that I don't think we would have found any other way.
Yeah mark. That's fucking insane how much psi that is in just .0 something milliseconds. Great video my man as well as heinrick for his observations. I love this shit though, I'm always happy to see technical stuff. And yeah abiatic sheer bands are super interesting. I got really into it researching tank shells penetrating sloped armor . I'm also a high explosives nerd so I understand bristance and all that BS. Anyway great fkn job mark. Much love n fuck the dummies haha
Reloader and engineer here. I like to look at energy density per grain of powder. I like to use a powder that isn’t the most dense because in the event I get a double charge I don’t want case room for a projectile.
That’s a good way to keep yourself safe. If the projectile fits in, you know you don’t have too much powder. If it were me, I simply wouldn’t ever use a powder that could detonate the biggest case I plan to reload. Air in the case is dangerous on its own too!
This is exactly why I decided to just load my own ammo. I can’t blame anyone but myself if something stupid happens. It’s also why I don’t mag dump any of my gun anymore. You would be surprised how easy a squib load can turn into a kaboom. Not to mention in today’s day and age with the demand for ammo. You would be seriously stupid to think that these ammo companies haven’t had a increase in defective ammo. I personally have seen with my own 2 eyes out of spec ammo. Projectiles upside down in the case cartridges with no powder in em. As of late brass that looks terrible dented tarnished and it’s supposed to be factory new.
I had some Sig 10mm JHP split/bulge casings, the recoil was ridiculous. They took it back immediately and replaced it, now the no longer use nickel plated brass and have dropped the velocity on new production.
I am the same way for the exact same reasons. There is only one other reloader I know personally whose ammo I'd shoot and that's only because they're as paranoid and careful as I am. Too many careless unknowledgeable people in this hobby and that makes me a little weary around newer guys, especially if they don't listen. Rules are often written in blood.
@@SuspiciousGanymede I don’t own a 10 mill yet. But the group of guys on UA-cam I am subbed to. Have said this exact same thing so I believe you brother.
That's what proof loads are for; you set the firearm at a certain level of PSI maximum and that's where you keep it and those PSI standards are set by the SAAMI organization. Bullseye powder is a double base, nitroglycerin; nitrocellulose pistol powder extremely fast burning. I used to reload a lot of my small cased pistol cartridges years ago with bullseye powder. It works great for operating blowback automatic pistols. One should never load this powder into a rifle cartridge; any rifle cartridge. As an engineer one should look at all those parameters and then again only shoot a SAAMI proof load to check your firearm when you're done testing it and recommend certain cartridges for shooting. I used to work for John Martz the Luger maker from Lincoln, California and that's pretty much the way he made his firearms, he would shoot a SAAMI proof load or two make sure that they would withstand the pressure and then recommend factory ammunition for shooting in them. He never reloaded or guaranteed the pistol with the use of reloads. One final thought about this problem is when your engineering a firearm for a new cartridge it's always, minimum pressure to attain maximum velocity.
Thanks for the great video. I had never heard of the Quick Load tool even though I have been reloading since 1960; what a great resource. I'm an engineer by profession and was a US Army Combat Engineer with some experience in demolition. Based on my experience and training I was certain the detonation was from a very rapid burning substance from the get go. Edwin pretty much confirmed by suspicions when he buried the muzzle or the RN-50 in concrete and the breech held up. Your analysis did a great job of verifying this. Two lessons should be learned from this tragedy. 1. The RN-50 has a very strong action. 2. Extreme caution must be used with any fast burning powder when reloading because a brain fart could be lethal.
Yeah, it reminds me of some other KaBooms that were caused by pistol powder in a rifle case. One that remember was a commercial reloading company that used the same machines for pistol and then rifle ammo. They didn't clear out the powder from 9mm loads when switching to 223. The other thing that came to mind was the series of KaBooms of 38 special revolvers blowing off the cylinder and top strap with light target reloads loads. The consensus was that the small powder charge lying horizontally in a relatively large, originally black powder case, was igniting all at once instead of the intended burn rate. It's one of the reasons that the large volume for weight power Trail Boss was introduced.
I remember those. Probably because I'm a max loads per pound guy. I wondered if the pressure went down, causing the powder to slow in combustion and the bullet to lodge. That results in an pressure increase to the point the powder acts like it should but now the bore is obstructed. Instead of the single curve we saw, you get a double curve resulting in RUD. You'd need strain gauges to tell, but it seemed plausible. We've all seen how powder burns when it's in the open with atmospheric pressure alone. Not very exciting.
Someone probably wanted to make a spicy cartridge to convince the buyer it was the real deal but screwed up the formula. Happens with street drugs so no surprise it happened with this very expensive ammunition.
@@no-sway3709 depends, scott tested the rest of the batch and they were all inconsistent, whoever did it botched the powder mix and ended up with uneven results, some that were fairly normal and others which likely wouldnt fair well in a normal 50 cal rifle but went okay ish from a slap variant rn50 like he was using, but obviously one of them was quite a lot spicier than the rest of the batch
I had the same theory back when the accident first happened that the "manufacturer" of the rounds was cutting rifle powder with pistol powder to "improve" performance. Probably some small amount of pistol powder, but enough that it altered the burn rate of the rifle powder and gave it that 'extra-spicy' that the manufacturer thought their customers were looking for. And was probably using someone who didn't understand what those powders actually do, to do the round assembly. My reasoning behind that is the round inconsistency among the non-accident rounds Scott fired. Reloading is meticulous work. Someone trained would have known that this kind of thing was outright stupid on the face of it, but there are probably ways to go about it with more safety (I won't say it was _safe,_ just that there are ways to make it _safer_ ) such as making sure the powder mix is accurate and consistent. The other rounds Scott fired weren't consistent enough for that meticulousness to be evident. Then during the manufacture of the accident round the untrained person's hand slipped, or something else stupid, and they got way too much pistol powder in the loading pan. "Well, I can't _unmix_ these... into the case they go, or at least as much as will fit." So you've got an already hot round round, with double or triple the "extra-spicy" that it's supposed to. The hammer falls on the round and you get a really fast burn, and you reach failure pressure on the breech-screw... and since the burn is still going the pressure is still going up. Fireball. Straight pistol powder would have been completely burned before the failure. There's evidence, I believe, that there was still burning powder in the fireball in the accident video. With mixed powders, the burn rate and peak pressure can get much higher much faster, but it couldn't have been _all_ pistol powder or even a majority. I also think the kind of pressure spike described by the reloading software would have turned the RN-50 into a bomb, rather than a "breech-screw cannon." I think the barrel and breech would have begun fragmenting (or at least expanding) and Scott would have had _much worse_ of a day. So my thought is that there was enough pistol powder in the mix to cause a 200k psi chamber pressure, at a less than 30ms rate (single frame between trigger squeeze and the tail end of the fireball) but not _enough_ to reach the theoretical 400k psi peak pressure for all-pistol powder load.
In the end it's about *power* so _the amount of energy released in a given amount of time_ . In this case: the energy content of the powder and the the time it takes to convert the total amount of chemical energy stored in the powder into hot gas. And while the specific energy content of the powder is interesting, it's the _specific energy content times the mass of the powder load_ that gives you the total amount of available chemical energy that will be released upon burning. Obviously you can compensate higher power densities by reducing the "dose", or increase the amount of powder when the potential energy per unit mass is lower. The gun was simply overpowered because the energy that was available in the powder was released *in a too short amount of time* Culprit: The burn rate factor. The Hodgdon BMG powder showed a burn rate factor of 0.2705 1/bar*s, whereas the pistol powders showed 3.63 and 4.7 respectively.
Thankyou for your video, i have lost hours playing in QuickLOAD and QuickTARGET, it is an essential and powerful tool in my reloading process. Also I have one of your bolt action rifles, the amount of fun that thing has been responsible for on the range, I've had mates grinning for days after trying your rifle. Your work is appreciated. Kindest regards Jez
I think in one of your previous videos I alluded to someone swapping a faster powder into the case. It’s the most plausible theory. I don’t use Quickload, and most reloaders don’t because we rely on verified and published loads. But, for those that wildcat or color outside the lines, Quickload is all that stands between their experiment and a blown up gun and it is a very powerful tool in the right hands.
Meh…. Firearms are often/usually tested to at least 150% of the peak pressure. And that’s just testing….the firearms are generally capable of sustaining much higher pressures. For virtually any load cartridge, you can’t even load 150% of the max published pressure…not even close. You might get to 110%. Now, where things get crazy is when you mix pistol powder for rifle. Even so, the gun won’t necessarily explode. For example, I have a friend who loaded pistol powder into a 6.5CM case. The gun was an AI AX. The charge was enough to completely cause the case to “evaporate” except for a microscopic-thickness lamination in the chamber. The bolt was ruined, but AI was able to cut out the bolt and replace it, and the gun was good to go (including the barrel).
Yeah. For grain dust, it's the increased surface area that lets it burn faster. (Technically it's the increased surface area per mass). For propellants surface area is also a factor (canons use giant grains, pistols use something closer to powder). But with modern smokeless they also use additives to adjust the burn speed up and down, to whatever speed they want.
Mark you're the best, thanks for ALL this information, the charge was always suspect for me but have loved watching your detailed breakdown of the failure.
One RN-50 (out of hundreds sold) gets its back blown out on some sketchy ammo, and suddenly every basement dweller with internet is a gunsmith. Even when Scott himself admitted he shot some bad ammo, AND THEN WENT TO BLOW UP TWO MORE GUNS WITH OVERPRESSURED .50 BMG. If the guy who nearly died to such a catastrophic failure, clearly knowing his stuff about firearms, vindicated the gun and backed it up with his own research, that's all I need. The people slandering Serbu for a "faulty product" shouldn't pretend to care about Scott while actively going against what he himself concluded.
It's like I say with my guns: "I can only design it to work and be safe in the conditions I reasonably expect it to be used in, there's no way to "idiot proof" anything". I think I speak for most of us when I say that I really appreciate the effort you put into studying this case, and Vlog'ing it for everyone to see the process!
In QL I adjust Ba to true estimated velocity to actual velocity on starting loads. It improves quality of the output as you progress the powder charge usually. Helpful in finding OBT nodes. I hate admit it but I have apparently double charged a rifle case with B Dot. I was loading reduced loads. Became distracted and must have double charged a case. The powder didn’t overflow the case. When that round was fired, it turned a 3 lug bolt into a two lug bolt. The rifle manufacturer was kind enough to replace the bolt at no charge to me…. Thanks Ruger
Hmm, that's the second time I've heard of Ruger replacing a firearm even though it was the end user's hand load that destroyed it. My buddy use to hunt deer with a Ruger Blackhawk .44mag. He always hand loaded his hunting rounds and was constantly pushing the pressures. He finally made a mistake and it broke the top strap and cracked the cylinder. He wrote to Ruger about it, stating it was his own fault, included all the info on the load he used, and thought they might be interested in examining the failure for their own info. Ruger ended up sending him a brand new Blackhawk back along with a thank you note for sending the weapon and info to them. As much as I'm not a fan of the Ruger company for other reasons, you can't deny their customer service seems to be pretty damn good.
@@nou712 Nobody's saying the feds are after Scott, but they have in fact loaded high explosives into rounds and shipped them off before. That ain't even classified in the slightest at this point
@@nou712 lol their is actual documentation from the Vietnam war called Project Eldest Son where the Government did that against the Vietcong. This could be a case of someone intentionally sabotaged ammo that someone didn’t know about and sold it as legit. Remember Scott admitted to buying from a anon online seller. It could’ve easily been someone buying it.
I have never used 'energy density,' but I have used 'powder burn rate' when selecting a powder. I think both terms more or less move in the same direction. I don't use Bullseye or Red Dot in a rifle. A slower powder is better and gives a less violent, longer dwell time.
Energy density is different to ‘burn rate’, the energy density is the amount of available ‘explosive power’ per say cubic centimetre/cartridge, the burn rate is the reduced reaction time of the chemical combustion. Same with falling to earth, the quicker you stop the worse you end up, the quicker the powder burns the greater the change in the same amount of time.
@polurazonituc If he fires it in a gun not intended for that cartridge, oh well. We take that risk every time we go to a public range.. In 40 years I have seen a few detonations of other people's guns.
Good explanation Mark, and love the idea of using QL as learning material. This software is a god sent for hand loaders. Sadly, on the topic of hand loading, it's often more seen as a mystical art than a science. There are quite a few "well known facts" that "every handloader know" which turn out to be somewhat *incompatible* with the laws of physics... and out of specs powder charges are one of them.
Burn rate charts, pressures, SAAMI specs, and reloader handbooks, many of them. All are used every time I reload. Never become complacent. Never leave powder in the hopper. Double check your powder charge and if possible, use a high volume pistol powder. Almost impossible to double charge.
Ah that makes sense. Even if it weren't overloaded in terms of powder weight, the much higher explosive velocity causes massively higher chamber pressure.
All those parameters in Quickload are mostly there for advanced users who wish to tweak some settings for a different batch of powder, or to create enough data to run simulations of a powder type that isn't in the standard database. Given enough knowledge and instrumentation to obtain pressure/velocity numbers, it is theoretically possible to "reverse engineer" data for a new powder type and manually enter that data into Quickload. Basically, Quickload is one of those old school programs that don't hide what's under the hood and that have tons of features most users will never touch, just so a handful of experts out there can work seemingly magic.
@@michaelbaker8284 That's one of its many uses, yes. You can determine roughly what the pressure will be at the gas port with different loads and powders. Also useful whenever doing nonstandard things like subsonic .308, loaded for the lowest possible muzzle pressure out of a bolt action. It's not perfect, but gets you in the ballpark for a safe starting load and allows for simulating many different powders rather than having to buy them all for testing.
Really a shame how along with mass internet adoption, came the dumbing down off all programs and gui’s. I cringe how they’re “apps” now on windows. Even search engines have gone downhill, no more forums or scientific papers easy to find, instead it’s crap written for ppl with below room tempt iqs.
Now we just need someone to actually test it. We can look at paper all day and guess what was most likely. But until someone test it in the real world it's still just speculation. This is the first of his update videos that was truly disappointing. We all want answers. But it cant be rushed just because he wants to protect his name. He needs to test his theories in the real world before trying to claim anything to be facts. Its likely pistol powder could cause issues. But until someone puts one in a gun vice and sends it. We are still just guessing. You said it well, "never assume you know everything"
Excellent video and explanation, I even understood it! In radio the number one axiom is that everything affects everything and that is certainly true here also! the graphs also were a great help in visually understanding.
I've only seen this reflected in reloading books as " too little per case volume burns faster/unevenly and risks detonation at the extreme low end" and "mostly filled case prevents double-charge and burns more evenly" Cost of powder volume per charge factors in eventually, which is why I use Bullseye on all my semi-auto ammo, and my 38spl, but never my 357Mag. This is one of the reasons newer reloaders MUST stick within published data with few substitutions. Until you understand the numbers game it is way too easy to blow something/someone up by going outside the numbers.
The thing is those weren’t supposed to be reloaded they were supposed to be military issued and were counterfeit so I’m not sure how professional the person making the counterfeits cared to be.
i suspect it wasnt a mistake exactly. Maybe they didnt know what was gonna happen but i wouldnt be shocked if someone just wanted to make a buck and had pistol powder around. Coulda been a newbie mistake, but maybe not.
The rounds need to be traced to the source and investigated and taken out of circulation altogether. I find it a bit sus that we have heard from the reputable gun maker but the rounds haven't been investigated or taken seriously. there could be thousands of those dodgy rounds out there, it could be a guy making counterfeits or just a mistake or they may even be smuggled into the USA you never know for sure.
Great vid, Mark. I could absolutely see some goofball getting his powder mixed up. Pistol powder would certainly do it. Thanks for sharing the internal ballistic parameters. Keep it real. 🇺🇸
As a reloader I can say I’ve never chosen a powder based on energy density specifically. I have, however, chosen powders based on the barrel length and used slower burn rate powders so I get a complete burn with 22 and 24 inch barrels. I have found this puts less stress on my used brass, which for some rifles is getting ever harder to find. As a side note many of the slower burners tend to be stick powders that have less muzzle velocity loss at colder temperatures, during hunting season. Had a friend sight in at 100 yds, level shooting from a bench in 90+ degrees temperature. Come cold December shooting down at 20 degree angle at horizontal distance of maybe 30 yards and he’s mad cause the round goes high. How much of that cumulative error in ballistics was due to incomplete powder burn? My S.W.A.G. = some. Enough to make all the difference at that short distance? Probably not. But the real goal of hand loading is to decrease or eliminate variables to knows to increase accuracy.
The other big factor is semiautomatic action and weather the slower powder will cause overgassing issues. I learned that the hard way with a .308 rechambered M1. Broke a lug right off using what should have been safe loads.
mate i enjoyed and appreciate the videos and commentary on this issue. Ill be sending my deposit in the next week or 2 for my order. Have shot your product and cant wait to get my own....cheers
Immediate upvote for the TLDR right at the beginning. I'm going to watch the whole thing to learn more about what happened!!! UUUUGH GODDANGIT! Poor Scott. My friend had a similar accident with a revolver.
The only critique in this video that I would suggest is to show the difference in scale between burn time on pistol powder and rifle powder. You talk about it, and it makes sense to me, but for people who don't know, they might not make the connection between the burn times. To be clear, the graphs you show have the numbers - but highlighting the differences of the scales might help those less informed on what to look for. Maybe overlay the graphs somehow. Thanks for the video! Informative as always! Keep up the great work!
That was my first thought when this all started, That it was pistol powder or some other way of being extra hot. Possibly to make the rounds seem more impressive then they actually are or ignorance on reloading.
The counterfeiter probably assumed that people just wouldn't shoot it because of how valuable it is. Possibly he didn't even know that this was really dangerous.
What is missing in this series of videos? One iota of humility. At no time did the manufacturer step back and ask a very important question. Can we do better or rather can "I" do better to lesson the chances of injury if the gun fails in a similar manner again? And the answer is simple yes.
Yep. He spent the whole video with graphs and numbers looking for where to point a finger. If he made a safe weak point in the gun, there would be no blame to cast in the first place.
I didn't think there was much more to add from what I'd followed but the pistol powder theory seems very sound to me. It obviously works out in the math as the simulation suggests, and as a physicist I found the explanation reasonably well done too. I might have focused a bit more on equations and energy but thats what physicists do. But realistically just seeing the pressure curve should have explained it to pretty much everyone. Also not surprising the gun blew. I'm frankly more surprised it took so many shots if anything. On the gun's safety features, the one I know about is the rabbit ears. As far as I'm aware they do double duty, partly to ensure it can't close and fire if not fully screwed and partly as a backup should the screw fail. I'm sure there's more I've missed, though.
Mark this has been a very informative series. Your transparency and explanation of your investigation only raise your reputations value. For someone to take this much time and capital to follow up on this speaks volumes about your character. I'm glad Scott is ok and wish you both great success in the future
My mum used to help reload for big shoots and I would occasionally get rounds with no powder and have to bash the projectile back down the barrel or it would go the other way and I'd have the odd double charged rounds. Thankfully that was target loads and it never happened with my hunting loads so check mums work when she's helping reload on those late nights.
Engineering standard (somewhat simplified) is to build a structure to satisfy its lifetime function safely at 2-3x the maximum expected load. Since the 50bmg is expected to produce about 50kpsi pressure, designing a gun for 150kpsi would have been more than enough. Since these rounds produce 450kpsi, all normal engineering would have been futile. Note that most guns (handguns, rifles, tank guns, artillery, etc.) are designed around chamber pressures of 30-60kpsi. Yes pistols use faster burning powder, but they have also smaller powder loads, lighter projectiles and shorter barrels, so it evens out. The reason for this universal design choice probably has todo with gun weight and recoil control. You could probably design say, a 6" barrel handgun for 500kpsi that's safe up to 1.5mpsi proof loads. But then you have three issues: the bolt, breach and barrel would be enormous, the gun would weigh more than you can hold up with one or two arms and effectively, the cartridges would be enormous and the recoil from the gasses escaping out the barrel would rip the gun out of your hands and fling it into your face unless you mounted it on a hardpoint (with a recoil absorption system). By that point it defeats the purpose of a "handgun". The same "equation" applies to any size gun. A rifle at 500kpsi is no longer a rifle, but has to be mounted like a large caliber gun. A large caliber gun at 500kpsi has to be mounted like an artillery piece. An artillery piece at 500kpsi, well, the technology to mount that hasn't been invented yet.
Yup. ^THIS^ Thanks for simplifying the Physics to the extent that even the most feverishly-stubborn Bubba can wrap his thick skull around it Florian 😁👍 I hope this video and ^this comment from Florian^ finally settles the argument for all the thousands of pig-ignorant dumbasses who falsely and wrongly accused Mr Gun Designer/Gun Nut of not knowing what TF he was doing when he designed and built the RN-50, and I hope they (lightly... 🙄) choke on the large slices of delicious Humble Pie that they should be chowing-down on right about now 🥴🥮😋🤤 after months of screaming baseless allegations on topics they have zero-understanding of... 😊👍
This is how you handle this kind of shit: an honest and open analysis of the event, not via bullshitting and legalese. Respect to you Mr. Serbu, one of these days I'll have enough scratch to buy a pew pew from you, because this level of openness NEEDS TO BE SUPPORTED!!!
Scott's latest video (blowing up a DEagle) shows a GOOD example of a "fail safe" failure. Most of the explosion and shrapnel seems to go away from the "volunteer" with the most severe apparent damage being some severely scorched skin on the trigger finger.
@@ahalfsesameseedbun7472 Take a look at the most recent Kentucky Ballistics. The Desert Eagle used was a 50AE firing a ridiculously overcharged round into a blocked barrel.
To answer the question you ask of reloaders: Yes I use internal ballistics when working up loads. This is especially important for powders where there is no published data for the limited availability of powders. Thanks for taking the time to address this, vs distancing yourself from the incident.
The energy density of an orbital object is probably in there for considering "Rod From God" scenarios. Basically, dropping a tungsten rod on something from orbit is going to result in a fairly radical boom purely from kinetic energy. See also "Project Thor" and "Flying Crowbar."
Did anyone get his unspent rounds, or more rounds from the same supplier to analyse exactly what was in them? How did you determine it was pistol powder and the type?
If you mean Scott's slap rounds, he fired them all remotely in a video. Many had extraction issues and pressure signs but none blew up another rifle. The video is of course on his channel if you're curious.
The unspent rounds were well, spent in Scott's own testing As for the pistol powder, it's a matter of "what could make that much pressure in that scenario", and we see here exactly what fit the bill
Clicking in I was afraid I would have to watch the entire thing to get the conclusion, thanks for putting it right at the front. Oh, and I ended up watching through anyway because it was very interesting!
Hi Mark, I saw the similarities on this 7 months ago on " RN 50 Accident Preliminary Analysis" and commented there about it. It's really surprising to have an explanation for this "dummy" phenomenon ( the dummy being whoever loaded the pistol powder in the first place). For me finding that pistol powder was used to forcefully disassemble my friends ar15 was surprising, and relieving, and thank the gun gods that neither my friend nor Scott were seriously harmed in either incident. Thank you for your pursuit of the facts that led up to this incident!
Words of wisdom: if you think you're being meticulous, you're not being meticulous enough. If you THINK you're being safe, you need to up the safety. I've reloaded many thousands of round of ammo in pistol and rifle ammunition. It's safe, effective, and sometimes even necessary with old rifles.... but you can get yourself in a shitload of trouble really quick if you don't double check yourself. Also, don't use random loads off the internet. If it's not in a known reloading manual, or you don't have the engineering datum to back it up, it's not worth it.
Get a couple different manuals and read the literature in them. Yes, different powders have different burn rates. Some powders can be used for pistol, shotshell, and rifle while others are fitting for application specific to case and payload capacity. Search for a burn rate chart. There are tons of different powders available and some numbskull practices are the reason why firearms pop from reloaded ammo.
I would just advise to get a couple loading manuals, well before touching a press. Make the cheap investment of a couple books before anything else. It will give you some time to get familiar with everything before loading the first round.
I was thinking, what if RN 50 did not have those ears, but just solid block (like those in most break action weapons). I think it wouldn't stop the pressure but it would send 20 more pieces of metal into Scoats body.
the question then becomes what is the next weakest part after the threads fail and can they deform/fail at a rate to allow pressure to drop into a suitable range vs unscheduled explosive disassembly.
I really love watching these videos where you dive into the physics/engineering as I’m in school right now for mechanical engineering and it’s really neat seeing how these things I’ve been suffering through work in the real world. I’d love if you made more of these types of videos.
Thanks Mark 😉Glad I could help. Edit: tip for you reloaders that reloaders should already know, only reload one thing at a time. Only ever have one powder opened in front of you at a time. Then you will not use the wrong powder. Stay safe!
Depends a little on how you mean that. One type of ammo at a time, yes. Reloading in batches and work through stages is very reliable. If you have 50 rounds on the table with powder waiting for the seating, that’s a great time to visually check that they all look like the same fill point. Anything seeming high or low, dump and redo.
@@ReinQuest exactly 👌🏻
That’s one of the cardinal rules in reloading.
Seriously heinrick! You can only fuck that up once lol.
Yes! Been a long time since I did any reloading, being in UK-land. But N310 was a blast from the past because that was my favorite pistol powder, and speculated a while back that the problem was using that instead of a rifle powder. Can't remember what powder I used for rifle loads, but I do remember it being a different vendor so the packaging was completely different. Less risk of grabbing the wrong blue bottle.
I was also curious about energy density given issues around powder vs case volume to develop the pressures involved. I guess that would be a useful data point for wildcat developers looking to min/max cases to pressure curves, without encountering RED (Rapid Energetic Disassembly) issues.
I actually am undefeated at my local high-school for launching a melon. Most students in physics class built trebuchet, catapult, slingshot etc,. I opted for basically a giant potatoe gun. When I was dumb enough to shoulder fire it using a BBQ lighter tied to a redementary grip and a chamber filled with oxy-ecetylene, using cereal bowls bolted together for a wad, I nearly broke my arm. The melon flew to the heavens and I never found it. When the competition at school arrived it was made to be a cannon and was mounted at 45 degrees and aimed off into the empty lot. We lost site of the fruity projectile and the school shut the show down pretty quick. To this day I have a plaque as the record holder which reads "distance unknown"
🤣🤣🤣🤣 thats fuckin awesome
Haha, a true hero!
Fucking beautiful 😂😂😂 launched that melon to the stratosphere 😂😂
That's dam awesome!!
How far away from the cannon were you made to stand? I am assuming there was teacher supervision at the time of the event? I expect many people have had some experience with potato guns growing up, in a rural environment at least. Going as large as a watermelon had not crossed anyone's mind that the cannon could just become a large pipe bomb?
Hi Mark. It is OK to hate being wrong, and even better to still be able to learn from it. That is why I am here, to learn from everyone who knows better than I do about the topic. Thanks for not running from this one, it is fascinating! Cheers from Texas.
Sometimes it's good to be wrong and to be challenged. As long as you're not pushing lies as fact (or opinions as fact), then it shouldn't be a big deal, but more of a learning experience. We're all ignorant about some (many/most) things... and people would be shocked to learn that so much of what they Know to be true is actually lies. Even the smartest people in the world know almost nothing at all (when what they know is compared to what they don't know).
@@deucedeuce1572 And some of the smartest people in the world know things that aren't true and may never learn because they refuse to see others' viewpoints and learn that what they believed all their life is actually false.
whatr you talkin about man, these videos ARE him running from it! He isnt touching his design at all, just making these videos.
@@fettmaneiii4439 What if his designs had nothing to do with it and that ANY 50BMG rifle would have exploded with the same round? Do you know they wouldn't? (and is he not innocent until proven guilty?)
the design of the gun was just bad. threading an end cap on might be something for a zip gun.
Hi Mark, you mentioned a "couple of fail safes" that no one seems to have commented on. It surprised me the number of people who commented in various videos concerning this incident of the "dangerous lugs" that flew off and nearly killed Scott, IMHO for what its worth these "dangerous lugs" actually saved Scott's life! If you hadn't added them to your design to ensure complete closure of the breech then that end cap would have come straight back and there would have been a very red wet hole in the atmosphere where Scott's head should have been.
Cheers from the UK
Good point
@@Lofi.z34 Mark discussed reinforcing the lugs in a previous video. You eventually get diminishing returns. By trying to overengineer and reinforce the lugs they will be propelled at a greater speed with more energy when they do fail thus inflicting more harm on the user. I think people are putting to much emphasis on those lugs as a protective measure when their real purpose is to act as a way to ensure the screw cap is closed. If the gun fails spectacularly enough to where the screw cap comes flying back then your already screwed no matter how those lugs are reinforced.
@@Launchpad_McQuack_Is_A_Chad I'm not sure I buy his argument there, there is definitely room to reinforce, or reprofile them before that becomes an issue.
If you look at the rifle from the side, the "lug" seems to be formed by removing a section behind it, which then rises up again, and I don't see why it's necessary to do that at all, just have the top edge be uninterupted, if you do that, and the rifle still fails, you're dead anyway.
Theres a story about the introduction of metal helmets in the military, at first people thought that they caused brain injuries, when infact without the helmet, the person would be dead instead.
It's kind of like that.
"If the gun fails spectacularly enough to where the screw cap comes flying back then your already screwed no matter how those lugs are reinforced."
Correct, at some point you're screwed no matter what, but that is NOT a good reason to not introduce improvements.
The problem is now that any change to the design at this point would be a legal minefield, it could be viewed as an admission that there was something wrong with it, and cause legal action to be taken when it wouldn't otherwise be.
@@LeoH3L1 The round that blew the gun was well in excess of seven times that of what a slap round should be loaded for. Take a look at Scott's channel, he had previously been firing slap rounds for a good 3 years at least with many of those being from the RN-50. The round that blew the gun has been shown to be able to blow several types of .50 caliber rifles. An incident like this is not a cause to try to make the gun fail safely for something well over 5x what the gun is rated to handle. The gun's failure point is already above and beyond what is required.
You don't wear a plate rated to stop up to .308 and then demand it be improved when it doesn't stop a .50 so why demand that of a gun when it is pushed beyond its rating?
@@Lofi.z34 to engineer out stupidity is a fools errand.
Stupid people do stupid things, pistol powder in this application is stupid.
Your transparency with this has been admirable. Kudos man. A trait seldom seen these days.
Hear hear.
transparency means little when he ultimately refuses to make his design safer when it fails.
@@fettmaneiii4439 Did you watch the video? The safety features were not at fault, the fault was traced to pistol cartridge powder being used in what should have been a rifle powder powered cartridge. MASSIVE difference. If you follow Kentucky Ballistics you'll see Scott, the guy who had the RN50 fail on him and damned near kill him testing various weapons to failure. They all handle correct loads as they should, but when loaded with excessive powder charges they ALL fail. Serbu's designs are not in question here. It was a secondary market issue, with someone using a powder vastly overrated for the intended purpose. THAT'S why the rifle exploded. It had nothing to do with any safety features incorporated into Mark's design.
@@fettmaneiii4439 It's a little hard to make something fail safely when it's over its design capacity by an order of magnitude.
There is no problem putting one liter of water in a one-liter bottle. Putting 10 liters of water in that same one-liter bottle poses some considerable problems.
@@fettmaneiii4439 To me it sounds like he's exploring failsafe mechanisms/geometry, and that it will be part of the next video.
And of course it should be made to blow up and break in a safer manner if possible. I agree with that. But mate, this was a freak round. I'd be surprised if the majority of experimental weapons don't lack the ability to fail safely when subjected to so much force, with bits and shards flying at the shooter and everyone beside them.
My BFG50 arrived a few days ago... it's because of how you handled this situation (and it's a beautiful gun) that I got it. No one expects perfection, but we want honesty and accountability.
Sig on the other hand is a great example of the opposite.
@Rawkem Sawkem Awesome, thanks! How long did you have to wait for the BFG?
@@markserbu Almost 12 months exactly
As I am not a reloader, I was shocked to learn that pistol powder burns that fast and creates that kind of pressure spike. Good to know, thanks Mark!
As a reloader of rifles I was surprised to learn that. However it does make sense when comparing burn time to barrel length
If you examine a few facts, it becomes OBVIOUS this would be the case. First, one needs an efficient burn in a far more abbreviated space. So, our pistol powder (which has reasonably equivalent energy density to a similarly compounded rifle powder) has to burn faster by design. Usually, this is done by varying size of individual "pieces" (grains is the usual nomenclature, but it's also the weight measurement unit in reloading, so let's call it "pieces" for clarity). "Traditional" rifle powders (like the IMR varieties) use tiny little cylinders as the "pieces" of powder. They vary from sewing needle to standard pencil lead diameters, with lengths between 1/10 and 1/4 inch. Pistol powders tend to be the smallest cylindrical sizes (very short length compared to diameter) or flakes. More modern stuff tends to be rough spheroids (ball powders) that use coating and additives to control burn rates.
Ok, burn volume is a function of surface area. Our chunky cylinder rifle powder "piece" rapidly loses surface area as it burns. Like a log in a fireplace, length shortens, diameter falls as it burns. Our tiny short skinny cylinder pistol powder burns more like a twig, same burn characteristics, but it gets consumed far faster than a log. Flakes burn like a sheet of paper tossed in the fireplace, foomp gone, muy rapido.
Smokeless powder has another whacky burn characteristic related to confinement. A tablespoon of powder dumped in an ashtray and lit with a match just kinda gives a slow fizzy greasy burn, it might take 2 seconds to burn out. Same in a proper sized case behind the right projectile, it burns several hundred times faster, and the higher the pressure the faster it burns.
Ok, so in the graphs shown we see an equivalent energy, the rifle powder is being subjected its natural environment. The pistol powder, however, assuming something like bullseye or hp38, is intended for mild pressure light target loads. It's already burning away far faster than the IMR type powder, but it's rapidly in an environment where pressure soars to 4 or 5 times it's normal conditions, causing it to burn even faster, creating even more pressure, causing faster burn, more pressure, ad infinitum.
Same potential energy, with a burn completion in 1/10 the time, equals equivalently higher pressure. The graphs and the realities of nitrocellulose burning in confinement agree 100%, though my bet is the loader building those SLAP rounds was using ball powder, had a hopper run empty, and grabbed one full of a pistol ball powder that "looked the same". That would put the final pressure somewhat lower than bullseye, but still FAR in excess of "mil-spec".
@@ludditeneaderthal Wow, thanks for the master class in the burn rate of different powders! Broken down the way you did, that makes a lot more sense about the differing burn rates of pistol vs rifle powders. Like I said, not a reloader, but I follow along with the explanation of the physics of gas pressure in a confined cylinder.(Here being the case itself.) Thanks for the lesson!
@@larrypelrine1799 also shotgun and pistol powders are darn near identical
One scary takeaway of this video:
Weighing a round loaded with the wrong type of powder would not reveal the problem.
certainly a "great" way to sabotage a round if you wanted to.
For example in the current Ukraine war. If the fleeing Russians had had available some sabotaged ammo they could have planted a few rounds.
They weren't planning to fail, though, and as a result wouldn't have any pre-sabotaged ammo. Theres another issue, it's really bad to have that around.
@@GeraldMMonroe even today there is still sabotaged surplus ak ammo floating around from the Russia afghan conflict
@@heatheryllanes6925 yeah it's actually a really bad thing to make. Your own soldiers may accidentally load it or unrelated innocent people may buy it.
@@GeraldMMonroe I'd be surprised if they are not doing it. Spiked rounds are not only for when you retreat, they are also for injecting into your enemy's supply chain. The Russian army must have a stash of it somewhere and I wouldn't put it past them to do such a thing
N310 is the fastest pistol powder in the Vihtavuori line, only the old blank powder is faster. We use it to make light subsonic loads and low recoil training loads for 7.62x53r The scale from ok pressure and way too much is really small, and to even thinking about having a full case let alone 50bmg case full of that stuff is very scary!
Sticking a bomb in the chamber it sounds like.
Hi MJ .. Norma R1, is the fastest burning powder then VV N310 then VV N 320 that is equal Bullseye..Personally I would not recommend using such a fast burning pistol powder in reduced rifle loads it is not required, you are asking for trouble ..Much safer to use the slower burning rated pistol powders you will get the same results and have more safety margins..good shooting..
@@ianbrown1058 Thanks smartass
@@ianbrown1058 He did say fastest in the Vihtavuori line, not fastest overall.
And I somewhat disagree with you on choice of powder for subsonic rifle loads, at least for use in European countries where suppressors are common and bolt action rifles are the norm. We don't have to care about gas port pressure, since we are not trying to cycle a semiauto. And the fastest powders allow for lower muzzle pressure, thus reduced noise, at the same muzzle velocity. Furthermore, in my experience loading subsonic .308, the fastest most easily ignited powders have the most consistent burns and velocities out of large cases. A typical subsonic rifle load with VV N310 and heavy bullets runs such low pressure that even a double load would be well within SAAMI max. Plenty of safety margin, it doesn't even expand the brass. And it gives good accuracy. So why bother with slower, less consistent powders unless you're trying to cycle a gas operated rifle?
So how does this get put into a 50 bmg round and sold to a random civilian? Is it as nefarious as it sounds to me? Is it a "spiked" round or an accident(i dont see how)?
Thanks so much for cutting to the chase and saying what happened right at the beginning of the video, so I could focus on the rest of the video knowing where we were heading.
I must say that your watermelon analogy is perfect for Scott’s accident. It explains everything. He just didn’t know that it was”WATERMELON TIME”!
Mark, that graph indicates that you should start making bench rifles in 30/40 caliber that can withstand 300,000 psi and shoot @ 6000 ft/s at 5 miles or so.
So basically take a 155mm field canon and re-chamber it to .50BMG.
Most modern powders run out of expansion at about 5000FPS, you 're not gonna get much beyond that unless propellants develop even further.
I built a test bed .177 cal BB gun when I was in tech school for machining, I ended up building a rifle that shot .177 steel BB's at a max velocity of just a tad over 5000 FPS, I could never get anything over 5100 FPS no matter how much more powder I loaded, it's about the peak limit of velocity with smokeless powder. I was putting an average of 6 grains, up to a max of 9 grains of .22 LR powder (about the fastest burning powder in existence) into the chamber and igniting it with 209 Winchester shotgun primers, I do believe I was exceeding 200k PSI of chamber pressure, since the chamber walls eventually began to bulge which is saying something, the ID of the chamber was only .240" and the OD was 1.500" and made of heat treated chrome-moly steel, as thick as many rifles firing full-size cartridges, yet it was starting to balloon out. The primers were immensely deformed after each shot, and it would put BB's through 3/16" thick steel plate lol. Moral of the story, at a certain point you're only putting energy into destroying your gun, in something like what I built where the powder load weighs over 1.5 times more than the projectile, there is no benefit. It took about three shots before the rifling disappeared, and it was on the tenth shot that the chamber started bulging out, I would have had to make the chamber two inches thick, maybe bigger, to be able to handle that kind of pressure and I would _still_ be swapping out barrels every dozen shots lol. It's cool and all but not in the slightest bit practical.
@@TheExplosiveGuy A BB-gun using powder as a propellant? That's more like BS-gun.
A BB-gun is always some kind of air gun. While the name of the gun comes from what it shoots, the shooting mechanism is integral part of the definition and can never be an explosive propellant. Otherwise nearly any gun could be referred to as BB-gun as most are able to shoot some kind BBs excluding rifled and choked barrels.
What you made is not a BB-gun but just a smooth bore rifle (a stupid misnomer, but I'll go with it) that shoots unconventional ammo for a rifle.
The fastest powders stop burning at ~5400fps, so you could get close
Seeing all the videos you’ve made about this incident and how much you’ve worked to understand why this went down has made me a life long supporter and hopefully future owner of Serbu firearms. Other companies could learn a thing or two from your dedication
All these rounds of ball slap are making me excited!
Even the proper rifle powder can become dangerous if the grains are broken....being their size and coating is one of the main controls to the burning rate. Degraded powder can also greatly increase in burn rate and can be very dangerous...and, of course if someone used a completely unsuitable powder is the other way bad things happen.
One other phenomenon that has happened is a partial fill charge of very fast powder basically detonating. Proper loading means the charge fills most of the case so its' position at the instant of ignition forces the fire to work its' way progressively through the charge. There have been many reduced 'target' loads blow up guns where these very light charges need the muzzle to be raised and rifle tapped before firing to settle all the powder back against the primer. If this isn't done the powder can stick all around the case and then the primer flash ignites it all instantly which causes a huge over-pressure.
I had a 45 Colt detonate once and instead of the normal 'pop' (this was with WW231) it went BOOM! with a bright muzzle flash. The normal rounds didn't make any flash so something bad happened. This was NOT a double-charge because I tried doing that with a 454 Casull and it wasn't near what had happened with the light charge. I doubt that's what happened to Scott's rifle, but just wanted to caution people to always use a powder density fitting the case.
The term degraded powder is kinda misleading according to what your saying then isn't it!?!?!?
@@diychad7268 No, that's the phrase used. Degraded, when talking ammunition, doesn't mean it doesn't work, it generally means it's going to burn a lot faster then it is supposed to. It's the same mechanism that can make a stable explosive unstable after storing for too long or improperly.
I've heard pistol powder in rifles = boom for a long time but having not gotten into reloading yet I never knew the math on just HOW bad it was... Those numbers are insane. You did a really good job breaking it down, thanks Mark.
Woah, I'm not a gun guy. I'm just a strong supporter of our rights to have them. I had no idea there was a difference in how quickly powder burns. The explanation made perfect sense. Thanks for the educational video.
Even different pistol powders have quite a wide range of pressure profiles between them. Easy to get in trouble if you don't pay attention.
That's the reason there are so many different brands. Different burn rates and some are made to take up more space to give you a slightly larger margin of error when it comes to charge weights. I WISH there was only one powder! lol
All the way down to tempurature ranges that they are stable in. I forget but every so many degrees of increase in temp will increase the velocity/pressure too. Causing shots to climb on paper if you shoot to fast.
Then there's also the whole thing about modern smokeless gunpowder versus old blackpowder.
Though smokeless powder charges of equivalent pressures can be loaded for guns rated for blackpowder (and this was done with commercial ammunition), the margins for error are pretty slim, and it's dangerous to experiment with, so the general rule of thumb is to just never put smokeless gunpowders in old blackpowder guns.
If you've ever seen a musket someone has tried to use smokeless powder in, the entire barrel will typically have violently twisted open and it looks like a big jagged metallic banana peel.
It's important to be mindful of what powders you are using and for what when you're loading your own ammunition (or shooting old muzzle loaders).
There are rifles chambered for pistol cartridges, but replacing the powder in a rifle cartridge with an equivalent volume of powder for a pistol turns it into a bomb.
there's a good reason why the propellant for a tank gun looks more like breakfast cereal rather then a powder ;-)
Thanks Mark,great explanation.
Good to hear a succinct explanation; Pistol Powder.
But ,why was only one round loaded with pistol powder? If you're making counterfeit ammo ,why would you load all the other rounds correctly and then just load one with pistol powder??
Definitely the Government
@@j.robertsergertson4513 How can you be sure only one round was loaded with pistol powder? For obvious reasons, no further shooting of the suspect rounds was done after Scott's near-death experience, so we don't know how many other rounds were similarly dangerous. We also don't know how many rounds were loaded in total. For all we know the person could have loaded hundreds or even thousands of those rounds, which could have been sold to any number of buyers besides Scott. If pistol powder were knowingly or unknowingly mixed with or substituted for rifle powder during part of the loading process and then the loaded rounds stored loose in a large container until they were ready to be packaged for sale, any particular package of rounds could have a random mix of rounds of varying danger levels.
Also, if the person who loaded the rounds designed the loads with pistol powder in mind, there's always the possibility that the load called for a small enough powder charge that there was room for an accidental double-charge. This could explain why several of the cartridges showed warning signs of excessive pressure, despite not blowing up the gun.
@@j.robertsergertson4513 Yaa da gubament haatees kentucky bruhlistiiics, gubament dun did it! it be da gubament!
@@j.robertsergertson4513 If you go back to Kentucky Ballistics' video originally detailing his original RN-50 detonating and his injuries, Scott showed footage of his other SLAP round shots into his fire hydrant target...and they were acting wonky (shots not penetrating or veering off). So it's possible multiple rounds in the lot he purchased were bubba'd with pistol powder but with lower potions...or some dingleberry "cut" rifle propellant powder with pistol powder and the round that nearly killed Scott was one where it was reloaded with just pistol powder or a mix where pistol powder was the main propellant type used.
I appreciate the dig at the security state.
Thank you Mark, we never stop learning and your explanation was very educational,looking forward to more content in the future.
Thank you for chasing this answer until the very end. It gives a better understanding of the "how" and "why" that I don't think we would have found any other way.
Yeah mark. That's fucking insane how much psi that is in just .0 something milliseconds. Great video my man as well as heinrick for his observations. I love this shit though, I'm always happy to see technical stuff. And yeah abiatic sheer bands are super interesting. I got really into it researching tank shells penetrating sloped armor . I'm also a high explosives nerd so I understand bristance and all that BS. Anyway great fkn job mark. Much love n fuck the dummies haha
Reloader and engineer here. I like to look at energy density per grain of powder. I like to use a powder that isn’t the most dense because in the event I get a double charge I don’t want case room for a projectile.
That’s a good way to keep yourself safe. If the projectile fits in, you know you don’t have too much powder.
If it were me, I simply wouldn’t ever use a powder that could detonate the biggest case I plan to reload. Air in the case is dangerous on its own too!
This is exactly why I decided to just load my own ammo. I can’t blame anyone but myself if something stupid happens. It’s also why I don’t mag dump any of my gun anymore. You would be surprised how easy a squib load can turn into a kaboom. Not to mention in today’s day and age with the demand for ammo. You would be seriously stupid to think that these ammo companies haven’t had a increase in defective ammo. I personally have seen with my own 2 eyes out of spec ammo. Projectiles upside down in the case cartridges with no powder in em. As of late brass that looks terrible dented tarnished and it’s supposed to be factory new.
I had some Sig 10mm JHP split/bulge casings, the recoil was ridiculous. They took it back immediately and replaced it, now the no longer use nickel plated brass and have dropped the velocity on new production.
I am the same way for the exact same reasons.
There is only one other reloader I know personally whose ammo I'd shoot and that's only because they're as paranoid and careful as I am. Too many careless unknowledgeable people in this hobby and that makes me a little weary around newer guys, especially if they don't listen.
Rules are often written in blood.
I founded 10% dented cases in a box of 50 5.56mm ammo. The supplier sent me a new box but it got by whatever QA was in place to start with.
@@SuspiciousGanymede I don’t own a 10 mill yet. But the group of guys on UA-cam I am subbed to. Have said this exact same thing so I believe you brother.
Thanks for all the info Mark, its amazing to see someone diving in to this and not just dismissing it.
That's what proof loads are for; you set the firearm at a certain level of PSI maximum and that's where you keep it and those PSI standards are set by the SAAMI organization. Bullseye powder is a double base, nitroglycerin; nitrocellulose pistol powder extremely fast burning. I used to reload a lot of my small cased pistol cartridges years ago with bullseye powder. It works great for operating blowback automatic pistols. One should never load this powder into a rifle cartridge; any rifle cartridge. As an engineer one should look at all those parameters and then again only shoot a SAAMI proof load to check your firearm when you're done testing it and recommend certain cartridges for shooting. I used to work for John Martz the Luger maker from Lincoln, California and that's pretty much the way he made his firearms, he would shoot a SAAMI proof load or two make sure that they would withstand the pressure and then recommend factory ammunition for shooting in them. He never reloaded or guaranteed the pistol with the use of reloads. One final thought about this problem is when your engineering a firearm for a new cartridge it's always, minimum pressure to attain maximum velocity.
I've actually seen published reduced power loads for bullseye in 30 06 and 308 NATO. No thanks.
Mark . Thanyou for finding the time to make this video. It's way over my head but I appreciate the fact you dumbed it down for people like myself!
Thanks for the great video. I had never heard of the Quick Load tool even though I have been reloading since 1960; what a great resource. I'm an engineer by profession and was a US Army Combat Engineer with some experience in demolition. Based on my experience and training I was certain the detonation was from a very rapid burning substance from the get go. Edwin pretty much confirmed by suspicions when he buried the muzzle or the RN-50 in concrete and the breech held up. Your analysis did a great job of verifying this. Two lessons should be learned from this tragedy. 1. The RN-50 has a very strong action. 2. Extreme caution must be used with any fast burning powder when reloading because a brain fart could be lethal.
Thanks for the follow up. Never doubted my RN 50 for a second.
Well done Mark.. going deep to understand the problem and his causes no matter what... Hi from Italy Very good Job Man ..
It was worth the wait thanks, still wouldn't stop me from owning a RN-50. Great video!
Yeah, it reminds me of some other KaBooms that were caused by pistol powder in a rifle case.
One that remember was a commercial reloading company that used the same machines for pistol and then rifle ammo.
They didn't clear out the powder from 9mm loads when switching to 223.
The other thing that came to mind was the series of KaBooms of 38 special revolvers blowing off the cylinder and top strap with light target reloads loads.
The consensus was that the small powder charge lying horizontally in a relatively large, originally black powder case, was igniting all at once instead of the intended burn rate.
It's one of the reasons that the large volume for weight power Trail Boss was introduced.
I remember those. Probably because I'm a max loads per pound guy. I wondered if the pressure went down, causing the powder to slow in combustion and the bullet to lodge. That results in an pressure increase to the point the powder acts like it should but now the bore is obstructed. Instead of the single curve we saw, you get a double curve resulting in RUD. You'd need strain gauges to tell, but it seemed plausible. We've all seen how powder burns when it's in the open with atmospheric pressure alone. Not very exciting.
Well, light loads is what filler is for.
That was fantastically educational. Thank you Mark
Someone probably wanted to make a spicy cartridge to convince the buyer it was the real deal but screwed up the formula. Happens with street drugs so no surprise it happened with this very expensive ammunition.
Not if they used pistol powder...
@@no-sway3709 depends, scott tested the rest of the batch and they were all inconsistent, whoever did it botched the powder mix and ended up with uneven results, some that were fairly normal and others which likely wouldnt fair well in a normal 50 cal rifle but went okay ish from a slap variant rn50 like he was using, but obviously one of them was quite a lot spicier than the rest of the batch
I had the same theory back when the accident first happened that the "manufacturer" of the rounds was cutting rifle powder with pistol powder to "improve" performance. Probably some small amount of pistol powder, but enough that it altered the burn rate of the rifle powder and gave it that 'extra-spicy' that the manufacturer thought their customers were looking for. And was probably using someone who didn't understand what those powders actually do, to do the round assembly.
My reasoning behind that is the round inconsistency among the non-accident rounds Scott fired. Reloading is meticulous work. Someone trained would have known that this kind of thing was outright stupid on the face of it, but there are probably ways to go about it with more safety (I won't say it was _safe,_ just that there are ways to make it _safer_ ) such as making sure the powder mix is accurate and consistent. The other rounds Scott fired weren't consistent enough for that meticulousness to be evident.
Then during the manufacture of the accident round the untrained person's hand slipped, or something else stupid, and they got way too much pistol powder in the loading pan. "Well, I can't _unmix_ these... into the case they go, or at least as much as will fit." So you've got an already hot round round, with double or triple the "extra-spicy" that it's supposed to. The hammer falls on the round and you get a really fast burn, and you reach failure pressure on the breech-screw... and since the burn is still going the pressure is still going up. Fireball.
Straight pistol powder would have been completely burned before the failure. There's evidence, I believe, that there was still burning powder in the fireball in the accident video. With mixed powders, the burn rate and peak pressure can get much higher much faster, but it couldn't have been _all_ pistol powder or even a majority. I also think the kind of pressure spike described by the reloading software would have turned the RN-50 into a bomb, rather than a "breech-screw cannon." I think the barrel and breech would have begun fragmenting (or at least expanding) and Scott would have had _much worse_ of a day.
So my thought is that there was enough pistol powder in the mix to cause a 200k psi chamber pressure, at a less than 30ms rate (single frame between trigger squeeze and the tail end of the fireball) but not _enough_ to reach the theoretical 400k psi peak pressure for all-pistol powder load.
Well that was a deceptively simple solution to the mystery that none of us thought of. Bravo, Mr. Serbu
In the end it's about *power* so _the amount of energy released in a given amount of time_ . In this case: the energy content of the powder and the the time it takes to convert the total amount of chemical energy stored in the powder into hot gas.
And while the specific energy content of the powder is interesting, it's the _specific energy content times the mass of the powder load_ that gives you the total amount of available chemical energy that will be released upon burning. Obviously you can compensate higher power densities by reducing the "dose", or increase the amount of powder when the potential energy per unit mass is lower.
The gun was simply overpowered because the energy that was available in the powder was released *in a too short amount of time* Culprit: The burn rate factor. The Hodgdon BMG powder showed a burn rate factor of 0.2705 1/bar*s, whereas the pistol powders showed 3.63 and 4.7 respectively.
Fly safe
Thankyou for your video, i have lost hours playing in QuickLOAD and QuickTARGET, it is an essential and powerful tool in my reloading process. Also I have one of your bolt action rifles, the amount of fun that thing has been responsible for on the range, I've had mates grinning for days after trying your rifle. Your work is appreciated. Kindest regards
Jez
I think in one of your previous videos I alluded to someone swapping a faster powder into the case. It’s the most plausible theory. I don’t use Quickload, and most reloaders don’t because we rely on verified and published loads. But, for those that wildcat or color outside the lines, Quickload is all that stands between their experiment and a blown up gun and it is a very powerful tool in the right hands.
Meh…. Firearms are often/usually tested to at least 150% of the peak pressure. And that’s just testing….the firearms are generally capable of sustaining much higher pressures. For virtually any load cartridge, you can’t even load 150% of the max published pressure…not even close. You might get to 110%.
Now, where things get crazy is when you mix pistol powder for rifle. Even so, the gun won’t necessarily explode. For example, I have a friend who loaded pistol powder into a 6.5CM case. The gun was an AI AX. The charge was enough to completely cause the case to “evaporate” except for a microscopic-thickness lamination in the chamber. The bolt was ruined, but AI was able to cut out the bolt and replace it, and the gun was good to go (including the barrel).
Makes absolute sense and this highlights the need to double check reloads and the competency of the reloader!
It's sort of how grain dust in silos explodes instead of simply catching fire quickly.
Flour explosions happen in Bakeries for the same reason and it's not common but it's not unknown
Yeah. For grain dust, it's the increased surface area that lets it burn faster. (Technically it's the increased surface area per mass). For propellants surface area is also a factor (canons use giant grains, pistols use something closer to powder). But with modern smokeless they also use additives to adjust the burn speed up and down, to whatever speed they want.
@@24680kong thanks for the insight
Mark you're the best, thanks for ALL this information, the charge was always suspect for me but have loved watching your detailed breakdown of the failure.
One RN-50 (out of hundreds sold) gets its back blown out on some sketchy ammo, and suddenly every basement dweller with internet is a gunsmith.
Even when Scott himself admitted he shot some bad ammo, AND THEN WENT TO BLOW UP TWO MORE GUNS WITH OVERPRESSURED .50 BMG. If the guy who nearly died to such a catastrophic failure, clearly knowing his stuff about firearms, vindicated the gun and backed it up with his own research, that's all I need.
The people slandering Serbu for a "faulty product" shouldn't pretend to care about Scott while actively going against what he himself concluded.
Thanks again Mark, I stll feel good about the RN-50
It's like I say with my guns: "I can only design it to work and be safe in the conditions I reasonably expect it to be used in, there's no way to "idiot proof" anything". I think I speak for most of us when I say that I really appreciate the effort you put into studying this case, and Vlog'ing it for everyone to see the process!
Thank you Mark! Keep up the awesome work!
In QL I adjust Ba to true estimated velocity to actual velocity on starting loads. It improves quality of the output as you progress the powder charge usually. Helpful in finding OBT nodes.
I hate admit it but I have apparently double charged a rifle case with B Dot. I was loading reduced loads. Became distracted and must have double charged a case. The powder didn’t overflow the case. When that round was fired, it turned a 3 lug bolt into a two lug bolt. The rifle manufacturer was kind enough to replace the bolt at no charge to me…. Thanks Ruger
Hmm, that's the second time I've heard of Ruger replacing a firearm even though it was the end user's hand load that destroyed it. My buddy use to hunt deer with a Ruger Blackhawk .44mag. He always hand loaded his hunting rounds and was constantly pushing the pressures. He finally made a mistake and it broke the top strap and cracked the cylinder. He wrote to Ruger about it, stating it was his own fault, included all the info on the load he used, and thought they might be interested in examining the failure for their own info. Ruger ended up sending him a brand new Blackhawk back along with a thank you note for sending the weapon and info to them. As much as I'm not a fan of the Ruger company for other reasons, you can't deny their customer service seems to be pretty damn good.
@@WildAzzRacing You can say a lot about Ruger, both good and bad, but their customer service is legendary.
Thanks for the geek out graphs. I learned today.
So as always, only handload if you know what you're doing, stay safe!
we all have learned how quickly Reloading a BMG turns into making a pipe bomb
Or you're the Government, trying deliberately to sabotage the ammo
@@j.robertsergertson4513 Yaa da gubament haatees kentucky bruhlistiiics, gubament dun did it! it be da gubament!
@@nou712 Nobody's saying the feds are after Scott, but they have in fact loaded high explosives into rounds and shipped them off before.
That ain't even classified in the slightest at this point
@@nou712 lol their is actual documentation from the Vietnam war called Project Eldest Son where the Government did that against the Vietcong. This could be a case of someone intentionally sabotaged ammo that someone didn’t know about and sold it as legit. Remember Scott admitted to buying from a anon online seller. It could’ve easily been someone buying it.
amazing video Mark. I loved the Wattermelon explanation Fitting since @KentuckyBallistics loves shooting them.
I have never used 'energy density,' but I have used 'powder burn rate' when selecting a powder. I think both terms more or less move in the same direction. I don't use Bullseye or Red Dot in a rifle. A slower powder is better and gives a less violent, longer dwell time.
Energy density is different to ‘burn rate’, the energy density is the amount of available ‘explosive power’ per say cubic centimetre/cartridge, the burn rate is the reduced reaction time of the chemical combustion. Same with falling to earth, the quicker you stop the worse you end up, the quicker the powder burns the greater the change in the same amount of time.
@polurazonituc It is the guiding principal behind such loads as 12 Gauge From Hell. :)
Always cracks me up when people claim to be able to differentiate burn rates of powder. Uh no. We are talking milliseconds. But you do you.
I use red dot regularly in several rifles and calibers, a pound goes much further.
@polurazonituc If he fires it in a gun not intended for that cartridge, oh well. We take that risk every time we go to a public range.. In 40 years I have seen a few detonations of other people's guns.
Thank you Sir! Always enjoy your work!
Good explanation Mark, and love the idea of using QL as learning material. This software is a god sent for hand loaders.
Sadly, on the topic of hand loading, it's often more seen as a mystical art than a science. There are quite a few "well known facts" that "every handloader know" which turn out to be somewhat *incompatible* with the laws of physics... and out of specs powder charges are one of them.
Burn rate charts, pressures, SAAMI specs, and reloader handbooks, many of them. All are used every time I reload. Never become complacent. Never leave powder in the hopper. Double check your powder charge and if possible, use a high volume pistol powder. Almost impossible to double charge.
"Don't presume malice if incompetence would suffice." It's way, WAY more likely that someone didn't know what they were doing.
You did a great job with the explanation.
I wish I lived in your area, it would please me to no end to work with you! 👍👍
Ah that makes sense. Even if it weren't overloaded in terms of powder weight, the much higher explosive velocity causes massively higher chamber pressure.
Thanks for the shout out to civil engineers!!
All those parameters in Quickload are mostly there for advanced users who wish to tweak some settings for a different batch of powder, or to create enough data to run simulations of a powder type that isn't in the standard database. Given enough knowledge and instrumentation to obtain pressure/velocity numbers, it is theoretically possible to "reverse engineer" data for a new powder type and manually enter that data into Quickload.
Basically, Quickload is one of those old school programs that don't hide what's under the hood and that have tons of features most users will never touch, just so a handful of experts out there can work seemingly magic.
I wish I had known about it as an average reloader because the time chart may be a useful tool to avoid potential overgassing in semiauto firearms.
@@michaelbaker8284 That's one of its many uses, yes. You can determine roughly what the pressure will be at the gas port with different loads and powders. Also useful whenever doing nonstandard things like subsonic .308, loaded for the lowest possible muzzle pressure out of a bolt action. It's not perfect, but gets you in the ballpark for a safe starting load and allows for simulating many different powders rather than having to buy them all for testing.
Really a shame how along with mass internet adoption, came the dumbing down off all programs and gui’s. I cringe how they’re “apps” now on windows. Even search engines have gone downhill, no more forums or scientific papers easy to find, instead it’s crap written for ppl with below room tempt iqs.
Thank you for putting in the effort to get to the bottom of Scott’s accedent keep up the good work
I hadn't thought of a pistol powder swap, but certainly looking at it now it is quite possible. Never assume you know everything.
Now we just need someone to actually test it.
We can look at paper all day and guess what was most likely. But until someone test it in the real world it's still just speculation.
This is the first of his update videos that was truly disappointing.
We all want answers. But it cant be rushed just because he wants to protect his name. He needs to test his theories in the real world before trying to claim anything to be facts.
Its likely pistol powder could cause issues.
But until someone puts one in a gun vice and sends it. We are still just guessing.
You said it well,
"never assume you know everything"
I was hoping nobody would be so stupid or unethical as to do that...
Excellent video and explanation, I even understood it! In radio the number one axiom is that everything affects everything and that is certainly true here also! the graphs also were a great help in visually understanding.
Can't wait to see your thoughts on Failsafe, and comparing the RN50 with all the other popular 50 cals on the market!
Wow. Such a fine example of quality content I absolutely love. Thanks Mark!
Thank you Mark! Hope to own one of your tools one day:)
always interesting videos, and I find it "especially fantastic that "this particular Florida guy", in this video is doing something productive
For reloading, yes we look at energy density....more case fill is accuracy and mass is money.
I've only seen this reflected in reloading books as " too little per case volume burns faster/unevenly and risks detonation at the extreme low end" and "mostly filled case prevents double-charge and burns more evenly" Cost of powder volume per charge factors in eventually, which is why I use Bullseye on all my semi-auto ammo, and my 38spl, but never my 357Mag.
This is one of the reasons newer reloaders MUST stick within published data with few substitutions. Until you understand the numbers game it is way too easy to blow something/someone up by going outside the numbers.
I appreciate the break down mark, well done. I've put off buying quick load for years but now I believe it's time
Pistol powder is what I have suspected all along. How an experienced reloader could make that mistake is beyond me. On purpose I'd say is more likely.
The thing is those weren’t supposed to be reloaded they were supposed to be military issued and were counterfeit so I’m not sure how professional the person making the counterfeits cared to be.
The Government does good work
i suspect it wasnt a mistake exactly. Maybe they didnt know what was gonna happen but i wouldnt be shocked if someone just wanted to make a buck and had pistol powder around. Coulda been a newbie mistake, but maybe not.
@@j.robertsergertson4513 They weren't real SLAP rounds.
The rounds need to be traced to the source and investigated and taken
out of circulation altogether. I find it a bit sus that we have heard from
the reputable gun maker but the rounds haven't been investigated or
taken seriously. there could be thousands of those dodgy rounds out
there, it could be a guy making counterfeits or just a mistake or they
may even be smuggled into the USA you never know for sure.
Great vid, Mark. I could absolutely see some goofball getting his powder mixed up. Pistol powder would certainly do it. Thanks for sharing the internal ballistic parameters. Keep it real. 🇺🇸
As a reloader I can say I’ve never chosen a powder based on energy density specifically. I have, however, chosen powders based on the barrel length and used slower burn rate powders so I get a complete burn with 22 and 24 inch barrels. I have found this puts less stress on my used brass, which for some rifles is getting ever harder to find. As a side note many of the slower burners tend to be stick powders that have less muzzle velocity loss at colder temperatures, during hunting season.
Had a friend sight in at 100 yds, level shooting from a bench in 90+ degrees temperature. Come cold December shooting down at 20 degree angle at horizontal distance of maybe 30 yards and he’s mad cause the round goes high. How much of that cumulative error in ballistics was due to incomplete powder burn? My S.W.A.G. = some. Enough to make all the difference at that short distance? Probably not. But the real goal of hand loading is to decrease or eliminate variables to knows to increase accuracy.
The other big factor is semiautomatic action and weather the slower powder will cause overgassing issues. I learned that the hard way with a .308 rechambered M1. Broke a lug right off using what should have been safe loads.
Great follow-up and explanation. Always happy to learn something new
Never use someone else's reloads ! I only trust what I loaded myself .Never forget that you gamble with your life if you trust other's reloads .
Around here friends gift each other boxes of reloaded ammo!
@@formolzinho Between trusted friends should be fine but mystery reloads are something different .
mate i enjoyed and appreciate the videos and commentary on this issue. Ill be sending my deposit in the next week or 2 for my order. Have shot your product and cant wait to get my own....cheers
Immediate upvote for the TLDR right at the beginning. I'm going to watch the whole thing to learn more about what happened!!!
UUUUGH GODDANGIT! Poor Scott. My friend had a similar accident with a revolver.
Thanks for being so transparent with this, when my situation stabilizes, I'll be looking into your firearms. :)
Oh this is _fascinating_
Outstanding Mark! Great information.
The only critique in this video that I would suggest is to show the difference in scale between burn time on pistol powder and rifle powder. You talk about it, and it makes sense to me, but for people who don't know, they might not make the connection between the burn times.
To be clear, the graphs you show have the numbers - but highlighting the differences of the scales might help those less informed on what to look for. Maybe overlay the graphs somehow.
Thanks for the video! Informative as always! Keep up the great work!
good point!
Great video mark always happy to see your new videos go up
That was my first thought when this all started, That it was pistol powder or some other way of being extra hot. Possibly to make the rounds seem more impressive then they actually are or ignorance on reloading.
Probably carelessness on the part of the loader. It happens on occasion, but the scale here is so massive it was very nearly deadly
The counterfeiter probably assumed that people just wouldn't shoot it because of how valuable it is. Possibly he didn't even know that this was really dangerous.
What is missing in this series of videos? One iota of humility. At no time did the manufacturer step back and ask a very important question. Can we do better or rather can "I" do better to lesson the chances of injury if the gun fails in a similar manner again? And the answer is simple yes.
This doesn't make much sense.
Yep. He spent the whole video with graphs and numbers looking for where to point a finger. If he made a safe weak point in the gun, there would be no blame to cast in the first place.
I didn't think there was much more to add from what I'd followed but the pistol powder theory seems very sound to me. It obviously works out in the math as the simulation suggests, and as a physicist I found the explanation reasonably well done too. I might have focused a bit more on equations and energy but thats what physicists do. But realistically just seeing the pressure curve should have explained it to pretty much everyone. Also not surprising the gun blew. I'm frankly more surprised it took so many shots if anything.
On the gun's safety features, the one I know about is the rabbit ears. As far as I'm aware they do double duty, partly to ensure it can't close and fire if not fully screwed and partly as a backup should the screw fail. I'm sure there's more I've missed, though.
Mark this has been a very informative series. Your transparency and explanation of your investigation only raise your reputations value. For someone to take this much time and capital to follow up on this speaks volumes about your character.
I'm glad Scott is ok and wish you both great success in the future
My mum used to help reload for big shoots and I would occasionally get rounds with no powder and have to bash the projectile back down the barrel or it would go the other way and I'd have the odd double charged rounds. Thankfully that was target loads and it never happened with my hunting loads so check mums work when she's helping reload on those late nights.
very good analysis. I'm glad to see you've come to conclusion on this one. I've been very curious about the blow up.
Engineering standard (somewhat simplified) is to build a structure to satisfy its lifetime function safely at 2-3x the maximum expected load. Since the 50bmg is expected to produce about 50kpsi pressure, designing a gun for 150kpsi would have been more than enough. Since these rounds produce 450kpsi, all normal engineering would have been futile.
Note that most guns (handguns, rifles, tank guns, artillery, etc.) are designed around chamber pressures of 30-60kpsi. Yes pistols use faster burning powder, but they have also smaller powder loads, lighter projectiles and shorter barrels, so it evens out. The reason for this universal design choice probably has todo with gun weight and recoil control. You could probably design say, a 6" barrel handgun for 500kpsi that's safe up to 1.5mpsi proof loads. But then you have three issues: the bolt, breach and barrel would be enormous, the gun would weigh more than you can hold up with one or two arms and effectively, the cartridges would be enormous and the recoil from the gasses escaping out the barrel would rip the gun out of your hands and fling it into your face unless you mounted it on a hardpoint (with a recoil absorption system). By that point it defeats the purpose of a "handgun".
The same "equation" applies to any size gun. A rifle at 500kpsi is no longer a rifle, but has to be mounted like a large caliber gun. A large caliber gun at 500kpsi has to be mounted like an artillery piece. An artillery piece at 500kpsi, well, the technology to mount that hasn't been invented yet.
Yup.
^THIS^
Thanks for simplifying the Physics to the extent that even the most feverishly-stubborn Bubba can wrap his thick skull around it Florian 😁👍
I hope this video and ^this comment from Florian^ finally settles the argument for all the thousands of pig-ignorant dumbasses who falsely and wrongly accused Mr Gun Designer/Gun Nut of not knowing what TF he was doing when he designed and built the RN-50, and I hope they (lightly... 🙄) choke on the large slices of delicious Humble Pie that they should be chowing-down on right about now 🥴🥮😋🤤 after months of screaming baseless allegations on topics they have zero-understanding of... 😊👍
Your factor of safety also depends on how predictable the load is.
Even modern tank guns only operate at about 90kpsi.
This is how you handle this kind of shit: an honest and open analysis of the event, not via bullshitting and legalese. Respect to you Mr. Serbu, one of these days I'll have enough scratch to buy a pew pew from you, because this level of openness NEEDS TO BE SUPPORTED!!!
Scott's latest video (blowing up a DEagle) shows a GOOD example of a "fail safe" failure. Most of the explosion and shrapnel seems to go away from the "volunteer" with the most severe apparent damage being some severely scorched skin on the trigger finger.
I feel like it's harder to make a failsafe in a 50 caliber tööb. Maybe if it use some sort of locking lugs instead of threads?
@@ahalfsesameseedbun7472 Take a look at the most recent Kentucky Ballistics. The Desert Eagle used was a 50AE firing a ridiculously overcharged round into a blocked barrel.
@@michiganengineer8621 I did watch it, but 50 ae is not nearly as powerful as 50bmg, and a Desert eagle has more moving parts that can fail.
To answer the question you ask of reloaders:
Yes I use internal ballistics when working up loads. This is especially important for powders where there is no published data for the limited availability of powders.
Thanks for taking the time to address this, vs distancing yourself from the incident.
I like the energy density list, don't bring your night sights anywhere near deuterium it'll be Bikini atoll all over again.
The energy density of an orbital object is probably in there for considering "Rod From God" scenarios. Basically, dropping a tungsten rod on something from orbit is going to result in a fairly radical boom purely from kinetic energy. See also "Project Thor" and "Flying Crowbar."
Did anyone get his unspent rounds, or more rounds from the same supplier to analyse exactly what was in them? How did you determine it was pistol powder and the type?
If you mean Scott's slap rounds, he fired them all remotely in a video. Many had extraction issues and pressure signs but none blew up another rifle. The video is of course on his channel if you're curious.
He shots them through a new rn50 to see if it blew up
The unspent rounds were well, spent in Scott's own testing
As for the pistol powder, it's a matter of "what could make that much pressure in that scenario", and we see here exactly what fit the bill
Yea kentucky ballistics sent them to mark with the blown up rifle
Kentucky used the remaining rounds to blow up another 50 cal rifle back in April on the anniversary of his accident
Clicking in I was afraid I would have to watch the entire thing to get the conclusion, thanks for putting it right at the front. Oh, and I ended up watching through anyway because it was very interesting!
👍🏻👍🏻 Makes sense.
Hi Mark, I saw the similarities on this 7 months ago on " RN 50 Accident Preliminary Analysis" and commented there about it. It's really surprising to have an explanation for this "dummy" phenomenon ( the dummy being whoever loaded the pistol powder in the first place). For me finding that pistol powder was used to forcefully disassemble my friends ar15 was surprising, and relieving, and thank the gun gods that neither my friend nor Scott were seriously harmed in either incident.
Thank you for your pursuit of the facts that led up to this incident!
I’m thinking about getting into reloading. So there is a difference between pistol powder vs rifle powder. Good to know.
Words of wisdom: if you think you're being meticulous, you're not being meticulous enough. If you THINK you're being safe, you need to up the safety.
I've reloaded many thousands of round of ammo in pistol and rifle ammunition. It's safe, effective, and sometimes even necessary with old rifles.... but you can get yourself in a shitload of trouble really quick if you don't double check yourself.
Also, don't use random loads off the internet. If it's not in a known reloading manual, or you don't have the engineering datum to back it up, it's not worth it.
Get a couple different manuals and read the literature in them. Yes, different powders have different burn rates. Some powders can be used for pistol, shotshell, and rifle while others are fitting for application specific to case and payload capacity.
Search for a burn rate chart. There are tons of different powders available and some numbskull practices are the reason why firearms pop from reloaded ammo.
I would just advise to get a couple loading manuals, well before touching a press. Make the cheap investment of a couple books before anything else.
It will give you some time to get familiar with everything before loading the first round.
Mark. Thank you. Great engineering explanation and an application explanation.
I was thinking, what if RN 50 did not have those ears, but just solid block (like those in most break action weapons). I think it wouldn't stop the pressure but it would send 20 more pieces of metal into Scoats body.
the question then becomes what is the next weakest part after the threads fail and can they deform/fail at a rate to allow pressure to drop into a suitable range vs unscheduled explosive disassembly.
I really love watching these videos where you dive into the physics/engineering as I’m in school right now for mechanical engineering and it’s really neat seeing how these things I’ve been suffering through work in the real world. I’d love if you made more of these types of videos.