Mark Serbu will be doing a full investigation once he recieves the parts and casing. Ian (Forgotten Weapons) also did a very good breakdown of catastrophic failures just a couple days ago. I want to thank YOU and everyone doing their best to figure out exactly what happened and how this can be rectified in the future.
@@MarcJaxon I think some people are worried that Mr Serbu will go "Right, checked it all out, gun was fine, very strong, definitely dodgy ammo!" and then scrap the bits. I'm not saying he'd do that and I honestly don't think he's that kind of person but that's what some people are concerned about. Like when the police investigate themselves.
@@Stigstigster and I get that. It is a rational concern. But I wasn't trying to suggest that Mark will be all alone in his creepy little design dungeon laughing maniacally while trying to formulate an "out" to save his ass.
@@MarcJaxon it's funny because mr serbu obviously has a vested interest in it not being his fault. For him to do the investigation on this would be like having the accused also act as the jury in his own court case
Really though, everything he says makes complete sense and with each tangent he goes he reinforces and expands the last, like piecing together a puzzle in thousands of minds
Do you know who is consider a criminal according to Biden opinion...? Police is a criminal... Criminal is police...why...? Because police protect people's right and the criminal protect dictatorship's right.
The way the whole of the internet’s gun gurus have come around this incident to investigate and offer their opinion based on their expertise is as heartwarming as it is frightening. It goes to show how seriously close to the long dirt nap KB came, but that we may all learn and educate from the incident brings joy and hope to my heart.
lets keep it real, its being exploited as a reason to make videos that they know will get a lot of views. maybe a couple are doing because they genuinely care, but most is just money. lol
The SLAP cartridge was designed for the Marine Corps to use in tank machine guns. It is not permitted to be fired through the M107 due to "hazards". This cartridge is dangerous to fire from anything other than a M2. I do not understand why nobody is talking about this. It needs to be said that people should not put SLAP cartridges into their rifles.
@@simplemann101 Not only is it a lost art, there is a broad contingent of UA-cam users that will actively mock comments containing words with more than one syllable. Anti-intellectualism is the bane of modern existence.
@@prasad530 The lust to fit in is indefatigable, and as such it's not worth posting most times. But again thank you for taking the time to be concise, your comment was spot on.
I work in incident investigation as part of my job. This kind of calm, thorough approach is what we aspire to maintain. I hope that Mr. Serbu collaborates with you on this topic and we see an actual root cause analysis.
@OmegaPaladin this channel is without doubt one of the finest on UA-cam for exactly these reasons, and is one of only a handful that leaves me feeling slightly less stupid than I was before I watched their latest video...
It reminds me of the kind of investigation that starts after an aircraft crashes. The more details you can understand, the more improvements you can implement to prevent future crashes. Good job.
@@tomupchurch4911 I'm leaning more towards "counterfeit parts", personally. Though it was definitely "Pilot error" to load the last round after the much bigger than usual muzzle flash from the previous SLAP.
@@FunnyHaHa420 made in Tampa Florida. He’s next to my best friends dad’s ac shop. Super nice and attentive guy. Met Mark when I picked up my RN50 at a gun show. I can’t think of a more passionate gunsmith I’ve ever met. He’s one of us, just way smarter. Lol
Man, this is single handedly the most intelligent and well made gun video I have ever seen on UA-cam. Definitely earned a sub from me. I don't think most viewers really understand your level of knowledge on mechanical and material properties.
This guy is a professional, well trained and educated in ballistics, chemistry, physics, engineering and metallurgy. Sadly, many YT gun channels are Fudds and Bubbas blowing up tannerite, thinkin' they know everthin' about guns. BTW there are other good channels like Forgotten Weapons, C and Rsenal, Mark Novak, but none with this guy's expertise.
I was going to post nearly this exact thing. As a certified gunsmith, i totally agree with what you stated and couldnt say better myself. Dude is top shelf info for free and isnt boring with his delivery.
I love that you address the importance of the location of the obstruction. You're the first person I've seen covering this that has made that distinction. People keep talking about the muzzle brake, but that's a complete red herring. The smaller version of the SLAP round was abandoned because of the tendency of the sabots to fragment in the bore resulting in the penetrator kicking to one side and hanging up in the rifling. It was less common in the larger .50 rounds, and when fired from the M2 it didn't destroy the weapon when it did, so they decided it was safe enough to push into production and use (I think the USMC did the testing on these, but don't quote me on that). If the polymer had gotten brittle from age or the round was loaded too hot, there's a good chance this is what caused the obstruction. It should be easy to tell when someone runs a scope down the bore because that tungsten penetrator would have torn a chunk of the rifling up if it made contact and hung, even briefly.
As a physicist with a long history of interest in firearms, I can certainly recognize a great gun channel when I see one. Instantly hit the Subscribe button! Thanks for your time and effort on this subject! I look forward to learning a lot here...
@@Gay_actor_Michael_Douglas If you scroll up, a mechanical engineer, with expertise in firearms ballistics gives a detailed analysis on what he thinks might have happened.
Very well presented. I work in safety (railroad), and was trying to look at this from a chain-of-failure point of view. Not a mechanical engineer, but your explanation is enough for me to understand the elastic, plastic, and shear things that I was pondering. When things fail, you look for friction, deformation, and mass to try and control the wayward force. Your mass statement was an "aha" for me. Much slower, but much heavier projectiles, but the science is the same. Keep up the good work!
You should definitely create a channel on firearms physics, modes of failure, engineering etc. You clearly have the aptitude and judging from the comments, a very interested audience.
TiborasuarusRex also did a video where he goes more in depth about sabot rounds and muzzle breaks. Where there doesn't have to be a visible obstruction to cause a catastrophic failure, among other hypotheses. Great video! I love how the gun community is coming together to figure all this out. You guys are great.
I seriously love the amount of attention within the guntuber community. Within a few days of Kentucky Ballistics video multiple guntubers released analysis videos, including our lord and savior Gun Jesus.
They're just hyping up the trend and making easy money with their lame excuses. You should be ashamed for disrespecting Christianity and the life of innocent who will lose their lives because of a failed design of a man who should be arrested. You will make the left win this war.
@@suprememasteroftheuniverse what in the fuck are you on? The RN50 is safe for normal ammunition, 55kpsi. .50bmg proof loads are 65kpsi, and every RN50 shipped is tested with one, by Mark Serbu himself, with his shoulder behind the gun so if it were to blow up Mark Serbu would be dead. The threads stripping off the cap that make the round that blew up KB's gun _at least_ 85kpsi, if not more. While there most definitely is someone at fault for this, it's not Serbu.
@@poppaganja3793 if the only difference is how much the ball protrudes it's normal, different ball shapes and weight can cause that. If the brass is different then it's a whole different problem
@@poppaganja3793 Inconsistent seating depth? Depending on how inconsistent it is it could be safe, my hang up is that if the loader didn't even bother to seat them to consistent depth I'd be worried about what else could be inconsistent. Honestly I would look for the ones that are seated the deepest and if there's too much of a different don't fire those. Bullets pushed too deep can cause overpressure.
@@bart5246 The difference between rounds would be visually noticeable just handling them, not to mention who would reload an American projectile in a Soviet case that happened to be sabotaged?
Very interesting and informed video! Thank you for this! I own a Serbu RN-50 and watching all the youtube gun nuts doing their expert takes and telling me that my gun is in fact still safe has been a big relief!
Just wanted to say thanks for all the great knowledge you share with us. It's great to see such great gun related content coming from elsewhere then the US and, I have tu say, you have great laws in Italy regarding firearm, atleast compared to Romania :)
Amazing description, best and most intelligent one i have heard so far. I hope Scott has a speedy recovery and the T-res leaves him alone while he recovers.
His RN50 had a beefed-up barrel. I wonder if in a standard rifle, overpressure from a sabot WOULD HAVE caused a barrel rupture, but with his having the heavy barrel sent to him by serbu, the barrel was no longer the weak point, and instead it was the threads on the breach?
Scott successfully shot an API round just prior to the accident, so I can't see any likely way there could have been a barrel obstruction when he took the last shot.
@@memeier9894 That's pretty much a possibility with EVERY design. A high enough over pressure event can easily turn the bolt into a projectile and/or shrapnelize the gun.
@@reaperreaper5098 with enough pressure sure, but a given volume can only produce so much pressure, and it should be designed in such a way that even if it fails catastrophically, it should do so in a manner that does the least amount of harm possible. In my opinion two little locking ears whizzing past your head and an end cap hitting you in the eye at mach 5 isn't it... I don't blame the rifle for failing, the ammo in my opinion is the culprit, but I do fault the manufacturer for the way in which it was designed or not designed to fail in.
Young man, your apparent knowledge in this area is not only amazing, it is helpful. Thank you for taking the time to make this very instructional video. bbb
You said interrupted threads just as I was thinking of them. Thank you for being one of the minority voices that brings facts, reason and understanding to the discussion. There’s to many youtubers who stayed at a holiday inn express and know exactly what happened with the same evidence as you b
The metal ears that help ensure the cap is fully seated also were ripped off by the force from the cartridge. They looked pretty stout, I wonder how much additional energy is required to destroy those too.
@@mattmurphy7030 Check any reloading manual and you'll see that there's a world of difference between a "normal looking" cartridge and a "normal acting" cartridge. Throw pistol powder into a .50 BMG case for example, and I defy you to find a gun that WOULDN'T explode from attempting to fire it. The difference between a cartridge and a grenade comes down to some fairly tiny details that an inattentive or inexperienced reloader can easily fuck up. There's a common warning in the reloading community that you should never, under any circumstances, fire a cartridge unless it came A: directly from an ammunition factory, or B: from your own reloading bench. I don't want to blame Scott for what happened, but if you make a habit of firing oddball rounds that you bought from "some guy," there's a good chance one of your guns will eventually blow up in your hands.
@@mattmurphy7030 I'm honestly not sure where else the shrapnel was supposed to go. Your face is right next to a gun when it fires, and if all that pressure can't go forward then "backward" is pretty much the only option left. I suppose the top of the chamber could be designed as the weakest point, but that would probably cause its own safety issues
This was an excellent video. I feel like you may have been too kind regarding the lack of fail safe design but i understand why you were. I'll definitely be watching more videos from this channel.
@Septic Whelk Serbu himself makes a 50 with an enclosed receiver that probably would have failed in a more safe way. Not zero risk of course, but probably less stuff hitting the shooter.
Wow, can't believe I didn't even think about the fact that most barrels are threaded into receivers or held on with a barrel nut as an example of why this method is sufficient lmao.
Threads are still more vulnerable to wear and damage from constant use. Cross threading can damage the first thread and grit can gradually erode. You don't unscrew and rescrew your barrel each time you fire. Suppressors for example have been moving to lugged quick connect systems away from threads partly for this issue.
@@ctrlaltdebug yes that's true about not unscrewing your barrel, still think it proves the base concept. Cross threading? You're doing it all by hand.. to cross thread it and cause serious damage you're going to have to ignore lots of warning and use alot of force to cause serious damage on threads that size. obviously if the threads become damaged that changes things.. Just like if a barrel extension or bolt lug becomes damaged in any other design.. sure there's wear on the threads just from normal use, but it's also a single shot .50, not something people are generally putting thousands of rounds through a year, especially not the person that bought the lowest cost .50 on the market. Threading on the end of most firearm nuzzles are alot smaller and would be more prone to damage or cross threading. Also, tri lug mount suppressors or accessories in general have been around for at least like 40 years, if there was such inherent issues with direct thread cans I'd think they'd be alot further along in phasing it out by now. The main advantage I think most people see from lugged or quick connect type cans is obviously the speed of taking them on and off but also not having to worrying about them walking off.
It's different with the barrel because the cartridge is in the barrel (or chamber) the chamber expands as the cartridge ignites tightening the barrel in the receiver making the joint more secure, plus the barrel is torqued into the receiver to begin with, not so with the breach cap on the firearm in question.
But it’s literally not. As correctly stated in the video it’s not that threads aren’t sufficient it’s that the placement of threads needs to be correct.
It's NOT that the rifle failed in an overpressure event, it's that it does NOTHING (design-wise) to DIRECT and CONTROL the FULL ENERGY (and Shrapnel) from the failure AWAY from the shooter. Mark Serbu's balance sheet is clear. $$$$ are more important than Lives.
Tibosaurus rex pointed out that slap rounds should not be used with any sort of muzzle brake - which was obviously fitted to Scott's rifle. Scott also mentioned that the muzzle flare appeared to be larger in the round he shot before the failure. Seems to be a line of investigation worth pursuing.
You're lying to defend a criminal who should get life in prison. You're Serbu's accomplices and also deserve to be arrested. The UA-cam gun community is a completely shame shamelessly jumping in this trend to make easy money making up excuses. Scott used a slap round. He's guilty. Serbu's guilty of his failed totally unsafe design. He said in a video that 50% was not enough safety and would like two or three times pressure resistance. Also Scott told him what kind of ammunition he would use and Serbu sent him a modified rn50. I hope he ends up in jail and all these channels are banned. You instead of saying the truth are trying to hide behind lies to not lose your fake jobs on UA-cam. That's absurd and unmanly. The left will win the war against gun rights and gun channels will finally be banned. Congratulations. Sadly leftists were right about most you in the end.
If anyone wants an update, there was pistol powder in the Slap round instead of rifle powder, which is VERY, VERY BAD, since pistol powder burns way faster than what you would use. The rifle itself was fine, but the pressure in the chamber was likely well over 150 000 PSI, while it is rated for 60k and was tested up to 85k.
One thing I noticed in the design that I haven't heard anybody comment on are the locking ears. If they were longer (or even extended back to the end of the lower) they would probably have not sheared off, and wouldn't have created the shrapnel that nearly killed Scott.
Everyone saying it was isn't educated on how they actually happen. Thank you for explains how and here and barrel volume and how fast pressures drop with that volume. Simple physics.
Amazed how the gun community can come together, without emotion and diagnosing a problem, and find a solution in a civilized manner. Gives credence to the old saying 'A polite society is an armed society'
In the end, the threads failed. It is true that we don't know the psi of the round, but we also can't presume that it was above a reasonable safety margin. Just a few questions that I have: 1.) The cap did not have a recommended torque value, nor was there one recommended by the manufacturer. Sufficient torque is required for this application. Less than adequate torque reduces thread engagement, and weakens the connection of the cap and barrel. 2.) In the instructions for the rifle, there is a recommendation for the application of masking tape to protect the barrel/cap when they can't be unthreaded without the use of a wrench or pliers. A problem like this is an indication of thread wear, distortion, corrosion, deposits or an improper thread design choice. Any of these problems will eventually result in a weaker thread engagement. This will eventually cause even more thread distortion/erosion, and this will increasingly weaken the cap retention strength. 3.) There is no provision for any venting of gasses in the breach as there would be in most bolt rifles. As the gasses are not controlled, some will escape through the threads. As they escape, the superheated gasses will change the properties of the metal where the gas escape is concentrated. As these areas are temporarily softened they are almost simultaneously hammered by the rearward movement of the cap. The temper of these areas will also be changed. 4.) It looks like the root of the thread remains on the barrel. This may be an indication of poor thread choice, improper machining tolerances, deformed threads, mismatched tempering or improper steel alloy match. 5.) The comparison of threads on the breech to the threads at the connection of the barrel to receiver isn't really a good one. The threads at the rifle/barrel connection are torqued, more often than not are screwed together once, should allow no gas escape through the threads, and when screwed together are much cleaner than the cap/barrel threads will be over time. Further, there are more threads in the receiver/barrel connection. 6.) There is an indication that the powder has a slower burn on the shot just before the problem. It's very possible that the load is different. The shot before that is also a bit strange as impact is a foot low and to the right. Even though the load of the rounds could be substantially different, both of these could be an indication of barrel obstruction. 7.) Any weakness would progress exponentially and that needs to be considered in strength calculations. It looks like your calculations are based on a new condition without any deterioration. We don't know what the deterioration was, but it was present. It's important that a statistically significant sample of the rifles be obtained for testing. It would be great if more of the ammo could be obtained and tested. I just don't see a simple solution to the problem. I'm sure you've considered many of these and you probably have excellent explanations. I am not an engineer. By the way, your videos are very interesting. Keep up the good work!
@@Phoenix_Atlas it would not be that much more expensive. All it would really do for that type of breech is add a couple more turning operations on the lathe and maybe another milling operation. Besides, I think it would be worth the extra $200-300 per gun to incorporate that kind of safety measure, especially after having such a public display of the inherent weakness of the screw on breech.
Brilliant review , and interrupted threads is a good idea. But I'm wary of anything that doesn't have a fixed hunk of metal between the bolt and my face lol...
Yeah I mean if you got money to buy a .50bmg rifle why not get either the bfg50 or the one I'd prefer which is the Armalite AR50? They're like a thousand bucks more which is a hell of a lot less than any hospital bill!
Done right, interrupted threads can also serve as gas vent holes pointing in a safe direction. When in the locked position, the milled-away portion of the threads line up to form wide open channels forward. Make these line up with relief cuts on the barrel so any leaked gas can safely vent forward away from the shooter, and Bob's year auntie. Of course, interrupted threads have less engagement area so you need a longer thread section for the same strength. Also, unlike a simple threaded cap these would need careful fitting so they close up with full engagement at the correct headspace, the current design is self headspacing and automatically corrects for wear or ammo variables by always screwing down to zero headspace. Thus, going to interrupted threads would increase cost and possibly reduce accuracy.
@@Kaboomf If I recall correctly what Mark Serbu said about why he didn't use interrupted threads, the two main issues were machining the threads themselves (apparently much more difficult than it seems), and more importantly adding an effective out-of-battery safety.
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Excellent video as always. Your position as a firearms examiner in legal cases, carries into this video in your delivery as well as graphs and formulas. As far as the threaded caps, home made shot guns, be they slam fired or with a crude firing pin arrangement, using galvanized plumbing pipe, have been around for a while. There are police and military photos of these crude guns that had failed, but usually at the welded seam, never at the threaded cap. I do agree with your first video that failsafes should be incorporated in future designs, and likely Serbu's liability insurance company may mandate them.
Thank you for another clear explanation. After watching your earlier comment video and some video’s of others I thought about the ammo, a point that some other commenters also raised. I know powder comes in grainy and in flaky form, and also in the form of strands (cordite) either or not with small channels running the lenght. The deflagration characteristics of a ‘powder’ depend in large part on it’s surface area. It would seem to me that this has a better chance of staying constant in a case when it comes in a cordite form, than when flakes or grains are used that can grind each other down due to movements such as caused by jogging or any kind of handling really. And by one in particular: ultra sonic cleaning, which might be done to give a fresher look to old ammo. It’s just a thought, no idea if anybody ever does this. I am no shooter myself, just watching gun video’s thanks to the algorithm.
Thank you for going over this failure/explosion/incident Scott is a very important person to me because of his videos being there during dark times in my life I don’t know what would have happened if GOD FORBID his life was lost i hope he gets some sort of cash reward and is recovering great I see the importance in firearm safety even the little stuff like eye protection now as well so THANK YOU for looking into this
I have been a serious firearm nerd for 48 yrs. I schooled myself in Mech Eng during HS - before I did 3 yrs of it at UNI. There was an issue with the loads. Recall that one or more loads did not impact where expected. I expect more wisdom from Mark S as he does the analysis of it. I still shoot a rifle labelled 110 yrs ago - as the Canadian Club. So I trust my life to an interrupted thread action. On Canadian Mil-spec ammo - all fine. Load some Brit or other ammo and you had a problem. I am trying not to be obtuse, but I do not wish to write a thesis. Be safe - be well!
The difference between a "Couch Forensic Investigator" and a "Professional Forensic Investigator" is that the Professional accepts the right answer even if it's a boring and uninteresting one and the Couch Forensic Investigator never accepts the right answer if it's not fantastic enough. Good video of course the threads failed from overpressure.
The difference between a couch forensic investigator and a ‘professional’ is the guy on the couch attacks the problem in his personal time because they’re passionate about it the process and quest for knowledge; the ‘professional’ just does it for money. You’re shitting (unnecessarily) on a lot of self made billionaires who began their careers as enthusiasts and for that you’re a POS.
In one of his earlier videos, I don't know if it is still up, but the maker said that the design did not have a great deal of margin of safety. He said it was plenty to handle the load that should be put on it, but didn't have much excess strength. This was obviously something that was on his mind at the time, but he decided that it was strong enough. In his defense, it should have been strong enough for regular loads, but many manufacturers who "proof" their firearms put almost as much powder in a cartridge as it will hold and test every weapon to ensure they can handle excessive loads. It usually shouldn't be necessary, but that safety margin could end up saving a life.
This video is 13/11 for sure! Thanks so much for this and thanks for this incredible analysis of the case friction topic. I really wonder how you became a ballistician though. Where do you start? Where do you obtain the knowledge? Is there schools for it? Because honestly, I am a mechanical Engineer and I know some qualified gun makers but most of the in depth ballistics knowledge is neither part of the first nor the latter. Would be really curious on how to get into the position you are in, just in case I start to hate my job one day haha
Idea for a reason: 1st. someone tampered with propellant 2nd. propellant degraded into smaller faster burning charge 3rd. booby trapped I want your opinion plz on 2nd explanation, can old ammo become dangerous overtime to shoot? Propellant goes into smaller bits, faster burning and more pressure creating??
Wow.....thank you for this analysis. Basically everything you said, I said to a friend of mine yesterday. As I have experience with barrel obstructions, I agree the damage occurs at the obstruction not on the receiver. And I agree with your analysis on threads this was what I said also. Threads are extremelly strong, just not practical for reloading a weapon. Good analysis.
Finally someone talking about that incident that knows what he's talking about!!! I think it is scary how many people on youtube still defend the design of that gun...
Love this kind of technical analysis/gun failure analysis videos!! I know you made one in the past but no more after that (except this incident). was it not successful enough? Or why else not make more?
Seriously though most through evaluation of the situation and the most removed from the event. You sir are an excellent detective.... id convict on your presentation regardless
I'd have to say that some clown tumbled that slap ammo for days to get the corrosion off of it and turned the powder into a superfine powder and increased the burn rate 10 fold. He probably bought them off gunbroker.
Or there was some moisture and uncontrollable pressure rise that ignite the whole charge at once, not burning controlled manner like it should but exploded.
Or these are 100% homemade with a lathe made penatrator. Homemade poly sabot that’s super clear and has no precuts. A shiny new case. And no crimp on it. Or link marks. Like every single original slap ever made. With who knows what powder in it. Being shot through a weird couple threads screw cap gun with a breach held together by a hollow thin pin.
@@mattmurphy7030 cause it was lol. But apparently if you go on mark surbu video blaming the ammo he just says cap is good for xxxxxxxxxxxxx amount of psi. Well 4 threads and a couple thin trunnions with a hollow pin was sorta left out.
@@mattmurphy7030 I mean I do feel bad for them both. One the one hand a good personality blew himself up with an extremely dangerous gun. On the other hand some good personality guy blew himself up with one of my extremely under failure guns... but I’m not going to allow ppls ignorance about a cap gun held together with 4 threads and a hollow pin. Or the extremely well known aspect of shooting any type of non complete metal projectile through a brake. Those things swell up as soon as it leaves the crown. And hit the brake. That’s why they don’t issue these to portable systems. They are only made and used on links in non brake 50s. Ppl can deny the brake all they want but it’s all right there. In big red letters in the manual.
WHAAAT, you mean to say that I can't load a 1oz slug in a 12 guage, use as much pistol powder that will fit in the shell, and shoot it safely? What kind of world do we live in. On another note, anyone looking to buy a broken 870, the barrel was weak and blew up on me. Also, anyone know any good prostetic manufactures for right hands.
Excellent analysis. I'll be interested to see how Serbu's analysis compares, since he'll have access to the firearm itself, but I'd wager it comes out about the same. Hopefully any changes deemed beneficial (because I'm not sure if I believe any are necessary, when it seems like the fault was due to a bad round) are not too costly.
Another excellent video on this topic. I'm so glad you have spoken up about this. I'm ALSO glad I watched this because you mention the SIG Blaser action. I own the "Tactical II" version of that rifle/action -- with 338 LM and 300 WM barrels; after your video, LOL, I am going to consider selling that rifle!
Just use good ammo. It would require irresponsibly over pressured rounds to have it fail. That said, do what makes you feel comfortable, no one can blame you for that.
@@sinisterthoughts2896 That is what Blaser claims. However, I personally know a guy with failed lugs. He only managed to fire a few factory loads before they let go.
From what I heard it was an out of production slap ammo that blew up the rifle. So this particular cartridge had probably changed hands several times and been laying around for many years. If the powder has been shacking around that much (50 BMG loads are not exactely compressed loads) it may have been made into a finer powder with a more rapid burn rate and therefore increased the pressure to dangerous levels. imho ;-)
It's amazing how many people spit that bullshit into each other's mouth. Yes it can be an issue. No, it's not frequently an issue with properly selected loadings. (Not much slosh) If that was a real issue, the vibration from firing something like a vulcan or GAU8 would in danger of blowing up every time you got to the end of a drum, wouldn't it?
Fellow armchair enthusiast here. When watching the gun explode in super duper slow motion - I notice that when it's fired, there is a brief flash at the muzzle followed by relief of pressure at each end of the receiver. Whats interesting is ignition only occurred at the breech-end while there was only a puff of smoke/powder at the back end... with no ignition. My conclusion is that the round he fired was one spicy tomato
First and Foremost "No fatalities" Second you virtually answered everybody's questions.. 1-Is it safe.... YES! 2-WAS IT SAFE IN SCOTT'S CASE.... "ABSOLUTELY NOT" The manufacturer will come to the conclusion to withdraw this rifle as they can't exclude the possibility of this happening again, due to the fact that if the ammo was bad or some barrel obstruction is to blame than the rifle should be designed as such to channel the damage away from the operator... NOT TOWARDS THE OPERATOR!!! Think Boing 737-Max....Is it safe, according to the Fda and Boing... Yes.... Did it crash multiple times... YES!!!.... If the manufacturers could turn back time would they produce this rifle or vehicle in question... "I don't think so...." Absolutely NOT" Think Tesla, are they absolutely safe... According to Tesla and Fmcsa... Yes!!!... As you all know, their batteries and driver less systems caused already BIG... BIG PROBLEMS, most of the time blamed on the operator!!! Make up your own conclusions, ultimately it's your life... You alone can decide... "What to drive"... "Which plane to fly"... "What rifle to shoot"...."Which woman to make your wife"... Etc.. Etc.
If you've never watched Serbu's video with Royal Nunsuch about the gun he says one of the problems is that he only has a %50 safety margin when he would prefer two or three times safety margin.
After rewatching the video, it's a little unclear when he says that whether he is referring to the prototype with the un-heat treated cap or the production models with heat treatment. In any case he hints around that they were trying to make it very light and hindsight looks like they may not have put all the safety features/robustness that they could/should have.
@@suprememasteroftheuniverse mainstream commercial guns, yes. Remember, this is the shop that made a super shorty and the gun buyback special. Boutique gear with their own idiosyncrasies. End user must exercise own judgment. Serbu talked about this some years back too, about that 50% margin.
I think a pretty amazing thing here is that his English is not only better than that of most who speak it natively, but it's better than that of most who speak it natively and would be considered eloquent.
I was thinking that due to the high speed of load application, inertial effects may not be negligible. This may cause that the applied load is much larger in some zones than others. I don't know if it is at least in the order of the speed of sound in the material. It is possible that since the ductility of metals is a function of the rate of stress application this could have not been considered. Steel ductility is much lower for impact loads and can certainly cause it to behave as if it was brittle. If the powder burns too fast you get overpressure and high speed load application, then you would only need the thread with highest load to fail to initiate a chain reaction. Materials mechanical resistance properties are always related to quasi-static load application and it is very important to take this into account.
That might be a possibility, these factors would certainly contribute, making it more likely to fail. but it also depends on the chamber dimensions and headspace of that particular firearm because these factors determine how and where would the brass case stretch and flow.
Backyard ballistic could it be hand loaded wrong powder or powder for stronger because of getting old as result I noticed muzzle flash was more than normal so rifle was compromised ? 👍🐾🦊🇮🇹🇬🇧
We can see in Scott's video how the first SLAP round made a small fireball and moved the grass around the table and we can see in Scott's body that it had more recoil, then the second made a 2 or 3 times size fireball moving the grass up to the fance on the right and had a lot less recoil and a total lost of accuracy, two rounds of supposedly the same batch had totally diferent behaviour, the third one exploded... so is likely that the rounds were bad reloads.
The wrong powder indeed can be calamitous, but aging powders sometimes become less stable and can generate wildly inconsistent and dangerous pressure levels as well.
Fantastic video. I’m was a proponent of metal fatigue causing the failure. However, Scott was using a different barrel/chamber with the same “plug”. In one video, he talks about how much easier it is to remove the spent cases from the new barrel. I thought that was really interesting. Could that make a difference?
Did Scott use the "faulty" cartridge to prize out the last cartridge - it looks like he did and Scott is a very big chap, could he have damaged/weakened the case during this action?
has nothing to do with the gun. its bad ammo that most likely exploded from the back (primer) instead of the front. there is a reason why shooting old ammo can be dangerous. there are many videos out there that show similar explosions from old ammo. Scott's cap was screwed in all the way, he showed it in the video. thanks for the interest though.
That's why I love gun-enthusiast content, although I strongly disagree with the worldview of most creators (and get regularly cringed by it, and getting REALLY weird recommendations by youtube, based on that). But it gives huge insights into material behavior under extreme conditions. And also guns are engineering marvels, beautiful beasts harnessing extreme energies with grace, elegance, and precision. I still believe the world would be better if not without them, but at least with much stricter rules and regulations.
Mark Serbu will be doing a full investigation once he recieves the parts and casing.
Ian (Forgotten Weapons) also did a very good breakdown of catastrophic failures just a couple days ago.
I want to thank YOU and everyone doing their best to figure out exactly what happened and how this can be rectified in the future.
"Mark Serbu will be doing a full investigation"
XDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
@@petermuller3995 I'm not really sure why this is funny...do tell.
@@MarcJaxon I think some people are worried that Mr Serbu will go "Right, checked it all out, gun was fine, very strong, definitely dodgy ammo!" and then scrap the bits. I'm not saying he'd do that and I honestly don't think he's that kind of person but that's what some people are concerned about. Like when the police investigate themselves.
@@Stigstigster and I get that. It is a rational concern. But I wasn't trying to suggest that Mark will be all alone in his creepy little design dungeon laughing maniacally while trying to formulate an "out" to save his ass.
@@MarcJaxon it's funny because mr serbu obviously has a vested interest in it not being his fault. For him to do the investigation on this would be like having the accused also act as the jury in his own court case
You would make an incredible firearms engineering teacher. You're quite articulate and intelligent.
Really though, everything he says makes complete sense and with each tangent he goes he reinforces and expands the last, like piecing together a puzzle in thousands of minds
I think his accent is fooling you, I swear I saw this man working the register at Walmart
Do you know who is consider a criminal according to Biden opinion...?
Police is a criminal...
Criminal is police...why...?
Because police protect people's right and the criminal protect dictatorship's right.
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The way the whole of the internet’s gun gurus have come around this incident to investigate and offer their opinion based on their expertise is as heartwarming as it is frightening. It goes to show how seriously close to the long dirt nap KB came, but that we may all learn and educate from the incident brings joy and hope to my heart.
he's practically a living medical miracle from what it sounds like. You can die under a half a minute from a lacerated jugular im pretty sure.
The RN-50 has probably already blown up before and killed someone and no one knows since it wasn't a big youtuber
lets keep it real, its being exploited as a reason to make videos that they know will get a lot of views. maybe a couple are doing because they genuinely care, but most is just money. lol
The SLAP cartridge was designed for the Marine Corps to use in tank machine guns. It is not permitted to be fired through the M107 due to "hazards". This cartridge is dangerous to fire from anything other than a M2. I do not understand why nobody is talking about this. It needs to be said that people should not put SLAP cartridges into their rifles.
@@thegettokidZz
That's if it's fully severed. Scott's was just cut, like a leaky break on a hose.
The professionalism and even-handedness of your presentation is commendable.
And a sweet accent.
It is only rivaled by the cogency of your comment. Written linguistics is a lost art on youtube comments, bravo my friend.
@@simplemann101 Not only is it a lost art, there is a broad contingent of UA-cam users that will actively mock comments containing words with more than one syllable. Anti-intellectualism is the bane of modern existence.
@@prasad530 The lust to fit in is indefatigable, and as such it's not worth posting most times. But again thank you for taking the time to be concise, your comment was spot on.
You can see that he is a professional
I work in incident investigation as part of my job. This kind of calm, thorough approach is what we aspire to maintain. I hope that Mr. Serbu collaborates with you on this topic and we see an actual root cause analysis.
Mark Serbu did comment on the previous video and said that the two of them needed to talk (in a good way).
@OmegaPaladin this channel is without doubt one of the finest on UA-cam for exactly these reasons, and is one of only a handful that leaves me feeling slightly less stupid than I was before I watched their latest video...
It reminds me of the kind of investigation that starts after an aircraft crashes.
The more details you can understand, the more improvements you can implement to prevent future crashes.
Good job.
Well put... so now we can call this pilot error?
@@tomupchurch4911 I'm leaning more towards "counterfeit parts", personally.
Though it was definitely "Pilot error" to load the last round after the much bigger than usual muzzle flash from the previous SLAP.
made in china fried rice stuck in the barrel.
@@grimreaper6112 Serbu isn't from China, it's from the U.S.A.
@@FunnyHaHa420 made in Tampa Florida. He’s next to my best friends dad’s ac shop. Super nice and attentive guy. Met Mark when I picked up my RN50 at a gun show. I can’t think of a more passionate gunsmith I’ve ever met. He’s one of us, just way smarter. Lol
Man, this is single handedly the most intelligent and well made gun video I have ever seen on UA-cam. Definitely earned a sub from me. I don't think most viewers really understand your level of knowledge on mechanical and material properties.
This guy is a professional, well trained and educated in ballistics, chemistry, physics, engineering and metallurgy. Sadly, many YT gun channels are Fudds and Bubbas blowing up tannerite, thinkin' they know everthin' about guns. BTW there are other good channels like Forgotten Weapons, C and Rsenal, Mark Novak, but none with this guy's expertise.
Na, you need to watch TIBORASAURUSREX'S VIDEO !!!!!
I was going to post nearly this exact thing. As a certified gunsmith, i totally agree with what you stated and couldnt say better myself. Dude is top shelf info for free and isnt boring with his delivery.
@@MrSmitty6969 Nah, not really. All was said here.
the knowledge is basic mechanical engineering stuff.
I love that you address the importance of the location of the obstruction. You're the first person I've seen covering this that has made that distinction. People keep talking about the muzzle brake, but that's a complete red herring. The smaller version of the SLAP round was abandoned because of the tendency of the sabots to fragment in the bore resulting in the penetrator kicking to one side and hanging up in the rifling. It was less common in the larger .50 rounds, and when fired from the M2 it didn't destroy the weapon when it did, so they decided it was safe enough to push into production and use (I think the USMC did the testing on these, but don't quote me on that). If the polymer had gotten brittle from age or the round was loaded too hot, there's a good chance this is what caused the obstruction. It should be easy to tell when someone runs a scope down the bore because that tungsten penetrator would have torn a chunk of the rifling up if it made contact and hung, even briefly.
The amount of knowledge that you are able impart on viewers is fantastic. Thanks for the video.
As a physicist with a long history of interest in firearms, I can certainly recognize a great gun channel when I see one. Instantly hit the Subscribe button! Thanks for your time and effort on this subject! I look forward to learning a lot here...
What do you think happened?
@@Gay_actor_Michael_Douglas If you scroll up, a mechanical engineer, with expertise in firearms ballistics gives a detailed analysis on what he thinks might have happened.
@@kwisatzhaderach9087 kinda vague, there tons and tons of comments.. up?!
@@RomboutVersluijs the video itself (sarcasm)
@@kwisatzhaderach9087 thanks to zoomer humor. im basically blind to simple sarcasm 🤣
Very well presented. I work in safety (railroad), and was trying to look at this from a chain-of-failure point of view. Not a mechanical engineer, but your explanation is enough for me to understand the elastic, plastic, and shear things that I was pondering. When things fail, you look for friction, deformation, and mass to try and control the wayward force. Your mass statement was an "aha" for me. Much slower, but much heavier projectiles, but the science is the same. Keep up the good work!
You should definitely create a channel on firearms physics, modes of failure, engineering etc. You clearly have the aptitude and judging from the comments, a very interested audience.
Your extremely professional & unbiased review of the incident is very endearing. Definitely earned a subscriber
Thank you for the detailed explanation, especially about how threads fail.
This is the best video I've seen on this topic so far. Well done!
TiborasuarusRex also did a video where he goes more in depth about sabot rounds and muzzle breaks. Where there doesn't have to be a visible obstruction to cause a catastrophic failure, among other hypotheses.
Great video! I love how the gun community is coming together to figure all this out. You guys are great.
This is by far the best information I have heard on this incident in the last two days. Well done sir!
I seriously love the amount of attention within the guntuber community. Within a few days of Kentucky Ballistics video multiple guntubers released analysis videos, including our lord and savior Gun Jesus.
Amen!
Lots of clicks to be had.
Better to be a living warning than a dead one!
They're just hyping up the trend and making easy money with their lame excuses. You should be ashamed for disrespecting Christianity and the life of innocent who will lose their lives because of a failed design of a man who should be arrested. You will make the left win this war.
@@suprememasteroftheuniverse what in the fuck are you on?
The RN50 is safe for normal ammunition, 55kpsi. .50bmg proof loads are 65kpsi, and every RN50 shipped is tested with one, by Mark Serbu himself, with his shoulder behind the gun so if it were to blow up Mark Serbu would be dead. The threads stripping off the cap that make the round that blew up KB's gun _at least_ 85kpsi, if not more.
While there most definitely is someone at fault for this, it's not Serbu.
Just found your channel. Your ability to articulate these concepts is outstanding. I know what im doing the next few hours. Thanks!!
For some reason I'm happy to hear that muzzle brake and sabots had nothing to do with failure.
"This can happen also on expensive guns, like the Blaser r93"
Thanks, now I'm afraid of handloading my Blaser ahahahah
I bought a bunch a reloads amd they all different sizes dose anyone know if that's bad ?
@@poppaganja3793 if the only difference is how much the ball protrudes it's normal, different ball shapes and weight can cause that. If the brass is different then it's a whole different problem
@@poppaganja3793 Inconsistent seating depth? Depending on how inconsistent it is it could be safe, my hang up is that if the loader didn't even bother to seat them to consistent depth I'd be worried about what else could be inconsistent. Honestly I would look for the ones that are seated the deepest and if there's too much of a different don't fire those. Bullets pushed too deep can cause overpressure.
@@bart5246 The difference between rounds would be visually noticeable just handling them, not to mention who would reload an American projectile in a Soviet case that happened to be sabotaged?
Blasers are a meme.
Very interesting and informed video! Thank you for this! I own a Serbu RN-50 and watching all the youtube gun nuts doing their expert takes and telling me that my gun is in fact still safe has been a big relief!
I thought I’d be over my head in the science jargon but you’re very good at explaining simply and concisely! You really deserve more subs!
Hai fatto una presentazione meravigliosa. Grazie per il tuo duro lavoro e impegno.
Just wanted to say thanks for all the great knowledge you share with us. It's great to see such great gun related content coming from elsewhere then the US and, I have tu say, you have great laws in Italy regarding firearm, atleast compared to Romania :)
Other good firearms content from outside the US:
Bloke on the Range
capandball
Polenar Tactical
The Armourer's Bench
Royal Armouries
Amazing description, best and most intelligent one i have heard so far. I hope Scott has a speedy recovery and the T-res leaves him alone while he recovers.
His RN50 had a beefed-up barrel.
I wonder if in a standard rifle, overpressure from a sabot WOULD HAVE caused a barrel rupture, but with his having the heavy barrel sent to him by serbu, the barrel was no longer the weak point, and instead it was the threads on the breach?
Scott successfully shot an API round just prior to the accident, so I can't see any likely way there could have been a barrel obstruction when he took the last shot.
I’ve been reloading ammunition for a long time and I would bet a lot of money on that round being over powdered or and extremely over crimp.
It was ......that rifle worked perfectly fine
@@CHOPMOP10 other than not having a design that if/when it fails doesnt send shrapnel and a 2 lb cap right into your face/neck area... its perfect.
@@memeier9894 That's pretty much a possibility with EVERY design. A high enough over pressure event can easily turn the bolt into a projectile and/or shrapnelize the gun.
@@reaperreaper5098 with enough pressure sure, but a given volume can only produce so much pressure, and it should be designed in such a way that even if it fails catastrophically, it should do so in a manner that does the least amount of harm possible. In my opinion two little locking ears whizzing past your head and an end cap hitting you in the eye at mach 5 isn't it... I don't blame the rifle for failing, the ammo in my opinion is the culprit, but I do fault the manufacturer for the way in which it was designed or not designed to fail in.
By the way, your viewership is creeping up quite nicely. I'm happy to see it. I've been here since 5,000? Maybe less. Keep up the fantastic work!
I first saw his channel after KB’s accident and along with many others have been plugging his channel.
Young man, your apparent knowledge in this area is not only amazing, it is helpful. Thank you for taking the time to make this very instructional video. bbb
You said interrupted threads just as I was thinking of them.
Thank you for being one of the minority voices that brings facts, reason and understanding to the discussion. There’s to many youtubers who stayed at a holiday inn express and know exactly what happened with the same evidence as you b
I absolutely love the engineering theoretical background you are giving! Keep up the good work
The metal ears that help ensure the cap is fully seated also were ripped off by the force from the cartridge. They looked pretty stout, I wonder how much additional energy is required to destroy those too.
I don't know the metric conversion, but in imperial units it's approximately 1 fuckton ± 1 shitload.
@@mattmurphy7030 Check any reloading manual and you'll see that there's a world of difference between a "normal looking" cartridge and a "normal acting" cartridge.
Throw pistol powder into a .50 BMG case for example, and I defy you to find a gun that WOULDN'T explode from attempting to fire it. The difference between a cartridge and a grenade comes down to some fairly tiny details that an inattentive or inexperienced reloader can easily fuck up.
There's a common warning in the reloading community that you should never, under any circumstances, fire a cartridge unless it came A: directly from an ammunition factory, or B: from your own reloading bench.
I don't want to blame Scott for what happened, but if you make a habit of firing oddball rounds that you bought from "some guy," there's a good chance one of your guns will eventually blow up in your hands.
@@mattmurphy7030 I'm honestly not sure where else the shrapnel was supposed to go. Your face is right next to a gun when it fires, and if all that pressure can't go forward then "backward" is pretty much the only option left. I suppose the top of the chamber could be designed as the weakest point, but that would probably cause its own safety issues
I think Serbu mentioned it was estimated they can hold 20k psi of pressure together before shearing off like that
This was an excellent video. I feel like you may have been too kind regarding the lack of fail safe design but i understand why you were. I'll definitely be watching more videos from this channel.
@Septic Whelk Adding emergency gas vents shouldn't add to the weight, if anything it might slightly reduce it.
@Septic Whelk Serbu himself makes a 50 with an enclosed receiver that probably would have failed in a more safe way. Not zero risk of course, but probably less stuff hitting the shooter.
Mark Serbu mentioned that you guys should talk (see comment on your last video). Have you had a chance to talk to him yet?
Imagine deciding you should talk to a physicist after you design and build a firearm.
@me Me they were surplus rounds. Why do you have to go around spouting off information that’s not correct. You’re assuming a lot....
@@Freakingstang They were sold as surplus rounds, who knows if they had been modified or reloaded or how old they were.
Wow, can't believe I didn't even think about the fact that most barrels are threaded into receivers or held on with a barrel nut as an example of why this method is sufficient lmao.
Threads are still more vulnerable to wear and damage from constant use. Cross threading can damage the first thread and grit can gradually erode. You don't unscrew and rescrew your barrel each time you fire. Suppressors for example have been moving to lugged quick connect systems away from threads partly for this issue.
@@ctrlaltdebug yes that's true about not unscrewing your barrel, still think it proves the base concept.
Cross threading? You're doing it all by hand.. to cross thread it and cause serious damage you're going to have to ignore lots of warning and use alot of force to cause serious damage on threads that size. obviously if the threads become damaged that changes things.. Just like if a barrel extension or bolt lug becomes damaged in any other design.. sure there's wear on the threads just from normal use, but it's also a single shot .50, not something people are generally putting thousands of rounds through a year, especially not the person that bought the lowest cost .50 on the market.
Threading on the end of most firearm nuzzles are alot smaller and would be more prone to damage or cross threading.
Also, tri lug mount suppressors or accessories in general have been around for at least like 40 years, if there was such inherent issues with direct thread cans I'd think they'd be alot further along in phasing it out by now. The main advantage I think most people see from lugged or quick connect type cans is obviously the speed of taking them on and off but also not having to worrying about them walking off.
It's different with the barrel because the cartridge is in the barrel (or chamber) the chamber expands as the cartridge ignites tightening the barrel in the receiver making the joint more secure, plus the barrel is torqued into the receiver to begin with, not so with the breach cap on the firearm in question.
But it’s literally not. As correctly stated in the video it’s not that threads aren’t sufficient it’s that the placement of threads needs to be correct.
You should start a segment where you just do videos on these sorts of topics
It's NOT that the rifle failed in an overpressure event, it's that it does NOTHING (design-wise) to DIRECT and CONTROL the FULL ENERGY (and Shrapnel) from the failure AWAY from the shooter.
Mark Serbu's balance sheet is clear. $$$$ are more important than Lives.
Tibosaurus rex pointed out that slap rounds should not be used with any sort of muzzle brake - which was obviously fitted to Scott's rifle. Scott also mentioned that the muzzle flare appeared to be larger in the round he shot before the failure. Seems to be a line of investigation worth pursuing.
You're lying to defend a criminal who should get life in prison. You're Serbu's accomplices and also deserve to be arrested. The UA-cam gun community is a completely shame shamelessly jumping in this trend to make easy money making up excuses. Scott used a slap round. He's guilty. Serbu's guilty of his failed totally unsafe design. He said in a video that 50% was not enough safety and would like two or three times pressure resistance. Also Scott told him what kind of ammunition he would use and Serbu sent him a modified rn50. I hope he ends up in jail and all these channels are banned. You instead of saying the truth are trying to hide behind lies to not lose your fake jobs on UA-cam. That's absurd and unmanly. The left will win the war against gun rights and gun channels will finally be banned. Congratulations. Sadly leftists were right about most you in the end.
@@suprememasteroftheuniverse you're grasping so hard at straws that don't exist.
The sabot obstruction was covered in this video as unlikely.
@@suprememasteroftheuniverse Dude, you're insane. Sincerely, a socialist.
It was explained at 4:44 that it would not blow the cap off.
If anyone wants an update, there was pistol powder in the Slap round instead of rifle powder, which is VERY, VERY BAD, since pistol powder burns way faster than what you would use. The rifle itself was fine, but the pressure in the chamber was likely well over 150 000 PSI, while it is rated for 60k and was tested up to 85k.
One thing I noticed in the design that I haven't heard anybody comment on are the locking ears. If they were longer (or even extended back to the end of the lower) they would probably have not sheared off, and wouldn't have created the shrapnel that nearly killed Scott.
That cap came off like a rocket....those locking ears would have to be a thick as a roll of dimes to contain that cap, just my two cents, cheers
Everybody's talkin' 'bout the threads of the cap, but what about those EARS?! The cap flippin sheared those things right off the gun!
I said this in Serbu's video that they should make them longer so if something like this happens it won't shear them off like that.
Jeez this guy is underrated by far!
Everyone saying it was isn't educated on how they actually happen. Thank you for explains how and here and barrel volume and how fast pressures drop with that volume. Simple physics.
Amazed how the gun community can come together, without emotion and diagnosing a problem, and find a solution in a civilized manner. Gives credence to the old saying 'A polite society is an armed society'
In the end, the threads failed. It is true that we don't know the psi of the round, but we also can't presume that it was above a reasonable safety margin. Just a few questions that I have:
1.) The cap did not have a recommended torque value, nor was there one recommended by the manufacturer. Sufficient torque is required for this application. Less than adequate torque reduces thread engagement, and weakens the connection of the cap and barrel.
2.) In the instructions for the rifle, there is a recommendation for the application of masking tape to protect the barrel/cap when they can't be unthreaded without the use of a wrench or pliers. A problem like this is an indication of thread wear, distortion, corrosion, deposits or an improper thread design choice. Any of these problems will eventually result in a weaker thread engagement. This will eventually cause even more thread distortion/erosion, and this will increasingly weaken the cap retention strength.
3.) There is no provision for any venting of gasses in the breach as there would be in most bolt rifles. As the gasses are not controlled, some will escape through the threads. As they escape, the superheated gasses will change the properties of the metal where the gas escape is concentrated. As these areas are temporarily softened they are almost simultaneously hammered by the rearward movement of the cap. The temper of these areas will also be changed.
4.) It looks like the root of the thread remains on the barrel. This may be an indication of poor thread choice, improper machining tolerances, deformed threads, mismatched tempering or improper steel alloy match.
5.) The comparison of threads on the breech to the threads at the connection of the barrel to receiver isn't really a good one. The threads at the rifle/barrel connection are torqued, more often than not are screwed together once, should allow no gas escape through the threads, and when screwed together are much cleaner than the cap/barrel threads will be over time. Further, there are more threads in the receiver/barrel connection.
6.) There is an indication that the powder has a slower burn on the shot just before the problem. It's very possible that the load is different. The shot before that is also a bit strange as impact is a foot low and to the right. Even though the load of the rounds could be substantially different, both of these could be an indication of barrel obstruction.
7.) Any weakness would progress exponentially and that needs to be considered in strength calculations. It looks like your calculations are based on a new condition without any deterioration. We don't know what the deterioration was, but it was present.
It's important that a statistically significant sample of the rifles be obtained for testing. It would be great if more of the ammo could be obtained and tested.
I just don't see a simple solution to the problem.
I'm sure you've considered many of these and you probably have excellent explanations. I am not an engineer.
By the way, your videos are very interesting. Keep up the good work!
I hope Mark remakes the RN-50 with some sort of interrupted thread breech like are used in artillery guns.
That would be a lot more expensive and I'm sure the rifle is designed the way it is to be cheap for a .50
@@Phoenix_Atlas it would not be that much more expensive. All it would really do for that type of breech is add a couple more turning operations on the lathe and maybe another milling operation. Besides, I think it would be worth the extra $200-300 per gun to incorporate that kind of safety measure, especially after having such a public display of the inherent weakness of the screw on breech.
@@elburropeligroso4689 the inherent weakness that is rated at 20000psi over what the caliber should top out at
@@elburropeligroso4689 a weakness that appeared at over 50% the maximum rated pressure of a .50bmg cartridge.
I hope he recalls all of them.
This is an impressive inspection with quality engineering references. Props to you bud.
Brilliant review , and interrupted threads is a good idea. But I'm wary of anything that doesn't have a fixed hunk of metal between the bolt and my face lol...
Yeah I mean if you got money to buy a .50bmg rifle why not get either the bfg50 or the one I'd prefer which is the Armalite AR50? They're like a thousand bucks more which is a hell of a lot less than any hospital bill!
Done right, interrupted threads can also serve as gas vent holes pointing in a safe direction. When in the locked position, the milled-away portion of the threads line up to form wide open channels forward. Make these line up with relief cuts on the barrel so any leaked gas can safely vent forward away from the shooter, and Bob's year auntie.
Of course, interrupted threads have less engagement area so you need a longer thread section for the same strength. Also, unlike a simple threaded cap these would need careful fitting so they close up with full engagement at the correct headspace, the current design is self headspacing and automatically corrects for wear or ammo variables by always screwing down to zero headspace. Thus, going to interrupted threads would increase cost and possibly reduce accuracy.
@@Kaboomf If I recall correctly what Mark Serbu said about why he didn't use interrupted threads, the two main issues were machining the threads themselves (apparently much more difficult than it seems), and more importantly adding an effective out-of-battery safety.
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Excellent video as always. Your position as a firearms examiner in legal cases, carries into this video in your delivery as well as graphs and formulas.
As far as the threaded caps, home made shot guns, be they slam fired or with a crude firing pin arrangement, using galvanized plumbing pipe, have been around for a while. There are police and military photos of these crude guns that had failed, but usually at the welded seam, never at the threaded cap.
I do agree with your first video that failsafes should be incorporated in future designs, and likely Serbu's liability insurance company may mandate them.
This only increases my knowledge on how to make homemade guns more reliable and safer.
Wow I m impress of your professionalism of your analysis. Thanks
If Ian is "Gun Jesus", "Backyard Ballistics" is "Gun Einstein". Great vid.
That's blasphemy. You should have more respect.
Insightful and informed commentary on a horrible accident, thank you.
Ive seen a lot of videos about this incident, and think the biggest lesson to be learned is. Be careful where you get your ammo from.
Thank you for another clear explanation. After watching your earlier comment video and some video’s of others I thought about the ammo, a point that some other commenters also raised.
I know powder comes in grainy and in flaky form, and also in the form of strands (cordite) either or not with small channels running the lenght.
The deflagration characteristics of a ‘powder’ depend in large part on it’s surface area. It would seem to me that this has a better chance of staying constant in a case when it comes in a cordite form, than when flakes or grains are used that can grind each other down due to movements such as caused by jogging or any kind of handling really. And by one in particular: ultra sonic cleaning, which might be done to give a fresher look to old ammo. It’s just a thought, no idea if anybody ever does this. I am no shooter myself, just watching gun video’s thanks to the algorithm.
Thank you for going over this failure/explosion/incident Scott is a very important person to me because of his videos being there during dark times in my life I don’t know what would have happened if GOD FORBID his life was lost i hope he gets some sort of cash reward and is recovering great I see the importance in firearm safety even the little stuff like eye protection now as well so THANK YOU for looking into this
I have been a serious firearm nerd for 48 yrs. I schooled myself in Mech Eng during HS - before I did 3 yrs of it at UNI. There was an issue with the loads. Recall that one or more loads did not impact where expected. I expect more wisdom from Mark S as he does the analysis of it. I still shoot a rifle labelled 110 yrs ago - as the Canadian Club. So I trust my life to an interrupted thread action. On Canadian Mil-spec ammo - all fine. Load some Brit or other ammo and you had a problem. I am trying not to be obtuse, but I do not wish to write a thesis. Be safe - be well!
The difference between a "Couch Forensic Investigator" and a "Professional Forensic Investigator" is that the Professional accepts the right answer even if it's a boring and uninteresting one and the Couch Forensic Investigator never accepts the right answer if it's not fantastic enough.
Good video of course the threads failed from overpressure.
The difference between a couch forensic investigator and a ‘professional’ is the guy on the couch attacks the problem in his personal time because they’re passionate about it the process and quest for knowledge; the ‘professional’ just does it for money.
You’re shitting (unnecessarily) on a lot of self made billionaires who began their careers as enthusiasts and for that you’re a POS.
Hey man, appreciated your humour in the last video. Too many painful bastards in this world. Cheers from Australia.
The cap tabs that sheared off could be beefed up or designed to deflect cap upwards maybe.
Not a gun person and Scott's video was a suggestion which lead me here. All I can say is I fucking love science application like this.
Scott is lucky to be alive. Maybe due quality of rifle or his skill. He’s lucky to be alive (ammo has to be the issue). Good content and presentation
@I need more constructive outlets its cheap for a reason
In one of his earlier videos, I don't know if it is still up, but the maker said that the design did not have a great deal of margin of safety. He said it was plenty to handle the load that should be put on it, but didn't have much excess strength.
This was obviously something that was on his mind at the time, but he decided that it was strong enough. In his defense, it should have been strong enough for regular loads, but many manufacturers who "proof" their firearms put almost as much powder in a cartridge as it will hold and test every weapon to ensure they can handle excessive loads. It usually shouldn't be necessary, but that safety margin could end up saving a life.
This video is 13/11 for sure! Thanks so much for this and thanks for this incredible analysis of the case friction topic.
I really wonder how you became a ballistician though. Where do you start? Where do you obtain the knowledge? Is there schools for it? Because honestly, I am a mechanical Engineer and I know some qualified gun makers but most of the in depth ballistics knowledge is neither part of the first nor the latter. Would be really curious on how to get into the position you are in, just in case I start to hate my job one day haha
Thanks for your engineering expertise on this issue.
Idea for a reason:
1st. someone tampered with propellant
2nd. propellant degraded into smaller faster burning charge
3rd. booby trapped
I want your opinion plz on 2nd explanation, can old ammo become dangerous overtime to shoot? Propellant goes into smaller bits, faster burning and more pressure creating??
Allegedly #2 is why Turkish 8mm surplus ammo is unsafe to shoot. Ian did a video on it.
@@hobofactory what's the video called? :)))
@@randomargument972 ua-cam.com/video/AunvMjcJPHY/v-deo.html
Wow.....thank you for this analysis. Basically everything you said, I said to a friend of mine yesterday. As I have experience with barrel obstructions, I agree the damage occurs at the obstruction not on the receiver. And I agree with your analysis on threads this was what I said also. Threads are extremelly strong, just not practical for reloading a weapon. Good analysis.
Your English is better than many American born folk !
That is not hard
LOL, Arky here and I am ashamed that I have to agree.
@@stevebettany8778 All you have to do is not say LIKE every other word.....
Finally someone talking about that incident that knows what he's talking about!!!
I think it is scary how many people on youtube still defend the design of that gun...
Love this kind of technical analysis/gun failure analysis videos!!
I know you made one in the past but no more after that (except this incident). was it not successful enough? Or why else not make more?
Seriously though most through evaluation of the situation and the most removed from the event. You sir are an excellent detective.... id convict on your presentation regardless
This is a much more scientific evaluation and much better than Trex was postulating with the slap sabot plastic build up.
Very informative! One thing to consider as well are the “ears” that were located behind the cap that were sheared off as well
I'd have to say that some clown tumbled that slap ammo for days to get the corrosion off of it and turned the powder into a superfine powder and increased the burn rate 10 fold. He probably bought them off gunbroker.
Or there was some moisture and uncontrollable pressure rise that ignite the whole charge at once, not burning controlled manner like it should but exploded.
Or these are 100% homemade with a lathe made penatrator. Homemade poly sabot that’s super clear and has no precuts. A shiny new case. And no crimp on it. Or link marks. Like every single original slap ever made. With who knows what powder in it. Being shot through a weird couple threads screw cap gun with a breach held together by a hollow thin pin.
@@mattmurphy7030 cause it was lol. But apparently if you go on mark surbu video blaming the ammo he just says cap is good for xxxxxxxxxxxxx amount of psi. Well 4 threads and a couple thin trunnions with a hollow pin was sorta left out.
@@mattmurphy7030 and the fact that your definitely not supposed to shoot sabots through brakes. Didn’t mention that either.
@@mattmurphy7030 I mean I do feel bad for them both. One the one hand a good personality blew himself up with an extremely dangerous gun. On the other hand some good personality guy blew himself up with one of my extremely under failure guns... but I’m not going to allow ppls ignorance about a cap gun held together with 4 threads and a hollow pin. Or the extremely well known aspect of shooting any type of non complete metal projectile through a brake. Those things swell up as soon as it leaves the crown. And hit the brake. That’s why they don’t issue these to portable systems. They are only made and used on links in non brake 50s. Ppl can deny the brake all they want but it’s all right there. In big red letters in the manual.
The informative content of your work is simply awesome!
Very interesting and well-stated evaluation of the event.
Wonderful explanation of all of the aspects.
Don't shoot too hot, not manufactured, and experimental rounds through any of your guns. Basically, a way overloaded handload.
Plus very old rounds that are available only between others private owners and not reliable sellers
WHAAAT, you mean to say that I can't load a 1oz slug in a 12 guage, use as much pistol powder that will fit in the shell, and shoot it safely? What kind of world do we live in.
On another note, anyone looking to buy a broken 870, the barrel was weak and blew up on me. Also, anyone know any good prostetic manufactures for right hands.
@@luxnova8211 🤣
@@luxnova8211 lol
Excellent analysis. I'll be interested to see how Serbu's analysis compares, since he'll have access to the firearm itself, but I'd wager it comes out about the same. Hopefully any changes deemed beneficial (because I'm not sure if I believe any are necessary, when it seems like the fault was due to a bad round) are not too costly.
great points
Another excellent video on this topic. I'm so glad you have spoken up about this. I'm ALSO glad I watched this because you mention the SIG Blaser action. I own the "Tactical II" version of that rifle/action -- with 338 LM and 300 WM barrels; after your video, LOL, I am going to consider selling that rifle!
Just use good ammo. It would require irresponsibly over pressured rounds to have it fail. That said, do what makes you feel comfortable, no one can blame you for that.
@@sinisterthoughts2896 That is what Blaser claims. However, I personally know a guy with failed lugs. He only managed to fire a few factory loads before they let go.
From what I heard it was an out of production slap ammo that blew up the rifle. So this particular cartridge had probably changed hands several times and been laying around for many years. If the powder has been shacking around that much (50 BMG loads are not exactely compressed loads) it may have been made into a finer powder with a more rapid burn rate and therefore increased the pressure to dangerous levels. imho ;-)
M962 SLAP-T runs 282 grains of a double base ball powder (equiv. Hodgdon H-380), it's pretty full.
It's amazing how many people spit that bullshit into each other's mouth.
Yes it can be an issue.
No, it's not frequently an issue with properly selected loadings. (Not much slosh)
If that was a real issue, the vibration from firing something like a vulcan or GAU8 would in danger of blowing up every time you got to the end of a drum, wouldn't it?
Fellow armchair enthusiast here. When watching the gun explode in super duper slow motion - I notice that when it's fired, there is a brief flash at the muzzle followed by relief of pressure at each end of the receiver. Whats interesting is ignition only occurred at the breech-end while there was only a puff of smoke/powder at the back end... with no ignition. My conclusion is that the round he fired was one spicy tomato
@Backyard Ballistics as Mark reached out to you in the comments to the last video, have you got in touch with him on this?
I'd also like to know
First and Foremost "No fatalities"
Second you virtually answered everybody's questions..
1-Is it safe.... YES!
2-WAS IT SAFE IN SCOTT'S CASE.... "ABSOLUTELY NOT"
The manufacturer will come to the conclusion to withdraw this rifle as they can't exclude the possibility of this happening again, due to the fact that if the ammo was bad or some barrel obstruction is to blame than the rifle should be designed as such to channel the damage away from the operator... NOT TOWARDS THE OPERATOR!!!
Think Boing 737-Max....Is it safe, according to the Fda and Boing... Yes.... Did it crash multiple times... YES!!!.... If the manufacturers could turn back time would they produce this rifle or vehicle in question... "I don't think so...." Absolutely NOT"
Think Tesla, are they absolutely safe... According to Tesla and Fmcsa... Yes!!!... As you all know, their batteries and driver less systems caused already BIG... BIG PROBLEMS, most of the time blamed on the operator!!!
Make up your own conclusions, ultimately it's your life... You alone can decide... "What to drive"... "Which plane to fly"... "What rifle to shoot"...."Which woman to make your wife"... Etc.. Etc.
If you've never watched Serbu's video with Royal Nunsuch about the gun he says one of the problems is that he only has a %50 safety margin when he would prefer two or three times safety margin.
Oh yeah I remember that. Where was that video again?
@@prfwrx2497 ua-cam.com/video/GR4jdHe6uiE/v-deo.html somebody grab it before it goes offline forever.
After rewatching the video, it's a little unclear when he says that whether he is referring to the prototype with the un-heat treated cap or the production models with heat treatment. In any case he hints around that they were trying to make it very light and hindsight looks like they may not have put all the safety features/robustness that they could/should have.
So he admitted his fault. I rest my case. Two times is the minimum you'll see in any commercial gun.
@@suprememasteroftheuniverse mainstream commercial guns, yes. Remember, this is the shop that made a super shorty and the gun buyback special. Boutique gear with their own idiosyncrasies. End user must exercise own judgment. Serbu talked about this some years back too, about that 50% margin.
Excellent Video and explanation of threads , strength , and gun design. Thank You !
I think a pretty amazing thing here is that his English is not only better than that of most who speak it natively, but it's better than that of most who speak it natively and would be considered eloquent.
I was thinking that due to the high speed of load application, inertial effects may not be negligible. This may cause that the applied load is much larger in some zones than others. I don't know if it is at least in the order of the speed of sound in the material. It is possible that since the ductility of metals is a function of the rate of stress application this could have not been considered. Steel ductility is much lower for impact loads and can certainly cause it to behave as if it was brittle. If the powder burns too fast you get overpressure and high speed load application, then you would only need the thread with highest load to fail to initiate a chain reaction. Materials mechanical resistance properties are always related to quasi-static load application and it is very important to take this into account.
Could it have been caused if the round was a re-load using a thinned case, hot load and over crimping of the neck?
That might be a possibility, these factors would certainly contribute, making it more likely to fail. but it also depends on the chamber dimensions and headspace of that particular firearm because these factors determine how and where would the brass case stretch and flow.
Biggest problem by far is gun did not fail safe
Thank you for a much more sensible and common sense theory
Backyard ballistic could it be hand loaded wrong powder or powder for stronger because of getting old as result I noticed muzzle flash was more than normal so rifle was compromised ? 👍🐾🦊🇮🇹🇬🇧
It could very well be a loading mistake. Actually, that's by far the largest cause of gun failure in general
We can see in Scott's video how the first SLAP round made a small fireball and moved the grass around the table and we can see in Scott's body that it had more recoil, then the second made a 2 or 3 times size fireball moving the grass up to the fance on the right and had a lot less recoil and a total lost of accuracy, two rounds of supposedly the same batch had totally diferent behaviour, the third one exploded... so is likely that the rounds were bad reloads.
Yeah, I had noticed it as well.
The wrong powder indeed can be calamitous, but aging powders sometimes become less stable and can generate wildly inconsistent and dangerous pressure levels as well.
@@sinisterthoughts2896 I think that was the biggest contribution to the kaboom.
Fantastic video. I’m was a proponent of metal fatigue causing the failure. However, Scott was using a different barrel/chamber with the same “plug”. In one video, he talks about how much easier it is to remove the spent cases from the new barrel. I thought that was really interesting. Could that make a difference?
Good video. Where did you get the graph at 5:04?
That's from quickload, a program for reloading ammunition.
Thank you posting. I enjoyed your engineering perspective on the subject.
Did Scott use the "faulty" cartridge to prize out the last cartridge - it looks like he did and Scott is a very big chap, could he have damaged/weakened the case during this action?
That's how you get spent cases from this RN-50 - You can't really damage the case this way. You would need to try really, really hard.
Just found your channel and watched like 30 videos.
Love your work
has nothing to do with the gun. its bad ammo that most likely exploded from the back (primer) instead of the front. there is a reason why shooting old ammo can be dangerous. there are many videos out there that show similar explosions from old ammo. Scott's cap was screwed in all the way, he showed it in the video. thanks for the interest though.
someone didn’t watch his last video
That's why I love gun-enthusiast content, although I strongly disagree with the worldview of most creators (and get regularly cringed by it, and getting REALLY weird recommendations by youtube, based on that).
But it gives huge insights into material behavior under extreme conditions.
And also guns are engineering marvels, beautiful beasts harnessing extreme energies with grace, elegance, and precision.
I still believe the world would be better if not without them, but at least with much stricter rules and regulations.