M855A1 Take 2 - It's not fake fellas
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- Опубліковано 21 жов 2024
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We address a couple of the questions/concerns about our previous M855A1 vs M855 comparison test video.
#M855 #M855A1 #testing
Lol, that extra 4" was just killing the velocity!
Some people ate way too many crayons when they were kids
Could've been lead paint also!
Oorah!
If they think such they should not be handling firearms.
Nobody made that claim. He doesn't understand how fast burning powders work, so he explained what everyone was saying wrong. Go back and read the comments.
No MAC is the dummy here. NO ONE said it was slowing the round down, they were saying that he wasn't comparing the rounds correctly because the military uses the M4 which has a 14.5 inch barrel, and was not displaying the qualities of a higher pressure faster burner powder that is used in the m855a1.
Unless a barrel is extraordinarily long, velocity will increase. Just because a load is optimized for a certain barrel length, doesn't mean a longer barrel will decrease velocity.
Granted, but what I was saying was that it was *optimized* for 14.5", so it should perform best there, whereas the M855 (or at least the M193) was likely optimized for 20" and should perform the best there. So, shoot them in an 18", the A1 likely won't be as much faster than anything else because that's not what it's optimized for.
The only reason to prefer a 16 for 855 is when the 855 has been passed around like a 9yo in Asghanistan... out of the longer barrels it has more time to fumble and fly like an ostrich due to the different twists.
I suspect that the "optimization" was more about mechanical functioning than bullet velocity. The "magic" round also has to function in the "long" barrel of the SAW. , but that is a whole other different can of worms.
One of the "issues" with the M4 and its 14.5" barrel is that it has a MUCH shorter gas tube. IF the system is set up with a barrel gas vent the same size as the 20" barrel the system will be somewhat "over-gassed". None of this is new. Remember that colt actually produced a "trials" carbine with a 14.5 inch barrel (Model 655), a LONG time before the M-4. As I recall, these pre-dated adoption of the M-16A1, so no "forward-assist". It also had a "standard" rifle butt, as opposed to the "adjustable variants the arrived with the XM-177 series.
"Over-gassing" is a good way to beat a rifle to death in short order. See also torn case rims and damaged extractors after a relatively limited time.
BTW, the 'issue" of the short gas tube and short barrel length was hashed over back in the 1960s / '70s, with the XM-177 series. LOTS of messing around with port size, buffers and the "muzzle device".
The latter was declared a "silencer for "reasons", even though in independent tests, it actually is LOUDER than a plain barrel; all dependent on where the sound metering gear is located. And "modern" audio test gear is a LOT better now than it was in the bad old days
HOWEVER, what the "muzzle device on these stumpy carbines ACTUALLY does is extend the "dwell-time" of the gas flow into the tube. Size DOES matter; especially gas-port size. The "muzzle device is a nifty exercise in high-intensity fluid dynamics. It "smooths out" the pressure spike of an "UN-compensated" barrel and reduces the battering on various components.
Hence, recent experiments with "pigtail" gas tubes (tubes that are extended and then wrap around the barrel) and assorted "expansion chambers"like miniature auto-style mufflers, tucked inside the hand-guard.
Depends on powder.
@@bruceinoz8002 They were trying to get 20" performance out of 14.5" guns. They optimized for that barrel and overcharged the heck out of it. Apparently, they lowered the charge due to pressure problems. Who would've figured, right?
20 inch barrel turns practice ammo into duty ammo
So does 45 acp ball lol
I love my 20inch wylde barrel 😁😁😁😁👍👍
@@evann1136not by itself do you not understand muzzle velocity?
@@reidiculous1 only if your duty is at extended range. Military's discovered in WW2, ( the Germans), that common engagement distances weren't at more than 300 meters, typically. So the need for full power hunting type cartridges was unnecessary. It didn't take long for them to figure out that at these new distances, a 24" barrel wasn't either. The longer barrel only becomes an issue at ranges greater than 500 meters. Calculating drops is a matter of mathematics. Granted, the formula changes with barrel length, but not that much really.
Are people really arguing that the 20” would be slower??? Even 300blk is faster in longer barrels even though it was designed for short barrels. Of course there is a length that would start to slow the round but nowhere near the common length of barrels available to consumers.
Yup, I'm no expert in ballistics, but these folks made me laugh. Gains may be minimal, but still gains. Would take a lot of barrel before slowing it down.
@@joshcarlson9352 Like 35-40" maybe more, lol
@@mfallen2023more like 100
The powder in the M855A1 is optimized for the shorter M4 barrel. Velocity gains after 18" of barrel is minimal. There probably is a barrel length where it starts to slow down, but that's probably 28"-32".
@@donwyoming1936even the inaugural power point of the A1 shows that there are barriers it can only defeat out of a longer barrel
The Army actually did dial down the pressures of M855A1. The original loads were almost at proof pressure and they were cracking bolts in M4s and causing cycling issues in M27s. The new, mass adopted M855A1 is now basically the same pressure as old M855.
Can confirm
@@nothim7321how long have the current ones been in circulation?
@@apricotcharms4126 as far as?
@@apricotcharms4126Chris at small arms solutions is trying to get a few batches of a1 from different years to find out the validity of the pressure changes
Can you provide a link to the source you're referencing? Or did your brothers cousins uncles son tell you?
"Apparently the velocities have been reduced, in terms of pressures of the cartridge, to address concerns of premature wear on the rifles...." (1:44) Let's apply that logic to the new hyper-pressure 6.8 NGSW cartridge and you'll see just one reason why that newly adopted cartridge is a huge mistake as a 5.56 replacement.
The 6.8NGSW will be shot with a rifle that was designed from the get-go to work with it, not with a 60+ year old design that is clearly facing the limitations of its age.
M855A1 is not a pistol cartridge. Why would anyone think it would slow down in an 18" barrel? LOL
Some people's kids.... Only naturally subsonic rounds 22lr and Sub 300blk can slow down out. Of really long barrels LoL
Super high pressure rounds have less improvement with longer barrels
@@hopewilliams67059mm out of a 16 inch barrel is slower than like a 10.5 or 12
Considering most standard issue rifles are M4's, 14.5" barrel. My guess is the round was designed to get max velocity out of a 14.5. If that's the case, it could begin to slow a bit from friction.
It all has to do with cartridge, bullets size and powder. All powders burn dif. U use faster burning powders if u want it all burnt up in a short barrel like pistols. And with rifles we use slower burning powders. Like u can shoot 30 30 thro a 16 to 20 in barrel on a lever action in which u use a slower burning powder or shoot 30 30 thro a thompson center pistol 10 in or 14 and u use a faster burning powder so u dont loose as much velocity and dont have as much not burnt going off as a fire ball after.
Some people think that when the powder completely burns the pressure in the barrel instantly drops and the bullet starts to slow, they don't understand that there's still pressure in the barrel, even if the powder is fully burnt, until the bullet exits. Even pistol cartridges will continue to accelerate down a rifle length barrel. Sure, at some point as a barrel gets longer and longer the pressure could drop enough for the friction to start slowing the bullet, but not at 18 or 20 inches and probably not even at 26.
Current loadings are Winchester brass, the hot stuff is 2012-13 by 2014/15 the pressure was reduced and standardized. The m855a1 is a good round the m80a1 is where it shines.
I've already seen other channels that were doing armor penetration tests on Steel using these same length barrels with the m855 A1 and they also got 3100 FPS+ going through a 20-inch Barrel, and it definitely makes a huge difference on target. Amazing Armor penetrating capabilities with 20-inch Barrel. Some people probably just haven't done much research on the subject if they thought the 20 inch barrel had that sort of effect slowing the projectile.
I have minimal knowledge of all the things that go into the velocity of a round. With that said, I will say the 20 inch will be faster. The 855 was designed for a 20inch barrel, thats what we used in the Army in 84
The way I understand it. We went places and shot bad people with the green tip, it poked little holes in them. Yes it penetrated better than the 55grn FMJ but that was the problem, it penetrated and zipped through leaving a small wound channel allowing the shot bad guy to continue being bad. The new round has it's penetrator exposed and crimped into the brass base. This is "fragile" in that when it hits flesh the hydro static impact causes the bullet to come apart and yaw creating a much better effect on the bad guy and still has the penetrator ability. Not too different than the Russians hollow cavity tip on their 5.45x39 both allow the bullet to "get damaged" to cause a better reaction to getting shot.
So they could accomplish the same thing by having a hollow point projectile?
@@denpabacon8501 No a hollow point only works for soft tissue. When you need penetration and damage a hollow point doesn't cut it. Also I believe the Geneva Convention forbids expanding bullets in war.
We never signed the Hague Convention( the convention on weapons used) and aren't fighting uniformed combatants.
Dude I love your little setup nice little work spot and a spot to test mods or upgrades rain or shine.. not a bad spot if you got neighbors no one can see you and I’m sure it reduces noise!! Got me thinking about something similar
Some gun guys will obsess over the smallest details placing waaaaay too much emphasis on some details. What my time sending lot of rounds down-range and collecting data reveals to me is this, STFU and git good scrub. The difference between various ammo, barrel lengths, bullet designs etc is always less important than staying sharp and pushing yourself to be better.
It becomes an obsession with some guys they obsess over 2 inches of barrel instead of just getting better with all rifles
Will it go "BANG!" and exit the muzzle with somewhat predictable accuracy and velocity? Yes? Great! NO? I'll find something else. At this point, the miniscule microdetails don't matter a BIT!. JMHO. YMMV.
The same gun guys won't get off the couch during elections.
The only thing that actually seems to make a difference for most shooters is optics. Irons to irons most people shoot the same with expensive gear vs cheap gear.
Yep. One of the worst shooters at my club had his dad buy him an HK MR556. Great kid, but he should have asked for $3500 in training instead of a new rifle.
The .556 was developed originally to perform best out a 20” barrel
There where no 5,56 in the original ;o) 5,56 came with the nato standard, and that has always been a 62 grain, and a 1in 7 barrel twist,, and had a higher pressure than the old 193 55 grain round 1 in 12 twist but yes , both where made for a 20 inch barrel
The King of Gun Reviews…. My favorite ACR vs SCAR, parts 1, 2 and 3. Been with you for years and years Amigo. Great channel, the best!
Excellent testing as always and right to the point. Very informative 👍🏻👍🏻👍🏻
Unless you’re competing, M855 and M855a1 are both pretty good for day and night use, and they store well. So if you’re getting animated over .7 MOA and 200 FPS difference in military grade ammo shot from military grade rifles, you’re probably ready for a trip to the range.
200 FPS difference in military grade ammo ?? that would never be acceptable, that would be faulty ammo ,
I meant the difference between M855 and M855a1. If I had two rounds of M855 were 200 FPS apart, I agree with you, that would be garbage tier ammunition.
The M855A1 performs better than M855. Barrier, not a barrier. Soft tissue or whatever else the A1 performs better and there is literally nothing on the market that will perform as good when considering both barrier and not a barrier.
M855a1 doesn’t penetrate as well as M995, it will never feed as well as M855, and both of them are heavier than M193. M855a1 is a good round, but it’s not a miracle. The shooter is still more important than the gun, so you should probably spend more time at the range and less time looking stupid on the internet.
@@jackjmaheriii they feed perfectly fine if you have proper equipment. Which if you are gonna be running those rounds you more than likely have the proper equipment already because the ammo is 1.expensive, and 2. Not the easiest to always find. Theres no feeding argument to be made here. M995 however will always be dominant but good luck finding that unicorn
Have we become so stupid that people don’t know longer barrels in general generate higher velocities 😑.
I pretty much see this as video game players thinking real life = the game and they also seem to think optimization = better, because video games taught them those ideas. >.<
You can probably assume the 'optimization = higher velocity crowd of people' as video game players not 'guys who shoot guns in the real world.' Yes, I play shooter games myself, but I also shoot guns in the real world. Guns in video games *does not equal* guns in real life.
One thing to note is that some of the material citing the velocity of M855A1 was done with conditioning of the ammo to 125F, which would bring the velocity up a bit over when you or I pull this out of our 70F home and go outside where it may be 85F
Exactly…I have to watch my handloads in this heat
No if you go back to the other video you probably won't find a single comment saying that. MAC just doesn't like admitting he was wrong for testing the rounds with an 18" barrel, even though the military uses 14.5 and the m855a1 was designed to increase velocity in shorter barrels lengths compared to M855.
@@weasle2904I’m confused by what you mean?
@@BuffRANGE The M855A1 uses faster burning powder that gives the round good velocity even out of short barrels. MAC used a 18" which doesn't show the difference between M855a1 and M855 properly in comparison to when fired out of a standard issue 14.5" M4.
@@weasle2904 Got it now. And I don't disagree one bit that M855A1 uses a better and optimized powder for shorter barrels. I will say though from my testing that better performance from that powder doesn't manifest until temperatures are over 80-85F. When I tested M855A1 through the full spectrum of barrels from 7.5" to 22" (the review is on my channel), our control of ZQI M855 was 30 fps faster out of the 10.5" vs M855A1. That was with temp of only 55F though.
Had to buy enough to fill 1 mag, just for SHTF. 30 rounds @ $2.50 each, $75.00 mag that will probably never get used.
Of course the velocity is equal or greater, the idea the bullet is going to slow down before the pressure drops off is dumb. The volume difference in barrel length is inconsequential compared to the gas expansion as it relates to bullet velocity. Silly, silly, silly.
Some people just don't understand how powder burns. There is no chance any rifle powder will be faster in a 3.5in shorter barrel.
I really hope no one thought the 18" barrell was slowing the bullet down. A 26" barrell wouldn't slow M855A1 down. The issue was people just wanted to see what it would do in other barrel lengths like 14.5" & 20". Edit:bullet
Mil ball ammo only fragments at 2700fps or higher. Full length gets those speeds up to 3100fps. Shorter the barrel less speed. Less chance of fragmenting less effective.
More like 2500fps for frag.
M855A1 Will undoubtedly be slower out of a 14.5" barrel. I am undoubtedly predicting that it will have higher velocities out of the 18" and 20" barrels.
I predict the 20" barrel produces 120 FPS more than the 14.5".
It's around 50-75 fps per inch up to 24". 5.56 is tested on a 20". .223 is tested with a 24" barrel.
Thanks Tim. Much appreciated as always.
I didn't think anyone truly thought it was slowing down the performance. More just being thorough.
All I can say is, when the A2 was picked up,I just smiled ear to ear.👍🇺🇸
Thank you for always doing great videos that are truly unbiased and show facts. The gauntlet with the 1911 was sad for me and we could truly see how much it let you down too. Semper Fi
The main advantage of M855A1 is consistency and better performance through barriers. The M855 had inconsistent terminal performance and only fragmented at higher velocities. The adoption of the shorter barreled M4 dramatically reduced its effective frag range. The "barrier blind" performance of M855A1 was especially wanted when US soldiers began to face more suicide car bombers. The standard M855 would tend to deflect and fragment upon hitting windshield glass, often allowing the driver to continue his attack. To a lesser extent, car doors and other barriers were a problem for the M855. It us useful to recall that the SS109/M855 was tested against steel helmets at distance, where simple penetration was the goal. In other situations, where the target is farther behind the barrier, it wasn't so good since the fragments were small and slowed dramatically.
Thank you 😊
For those who simply can’t comprehend.
Imagine if you will you throwing a football. The first throw is half arm or just flicking your wrist. Where does it go? Not never far and right to the ground.
2nd throw is your wrist and forearm. Goes farther and speeds up slightly. Still hits the ground.
3rd throw is the entire arm. Goes further, spirals faster, and eventually hits the ground.
4th throw is your entire arm and your body. Twist the hips, even take a couple of steps. The football goes the farthest and spirals beautifully.
This is what this video and many other videos explain on how longer barrels will always have the advantage.
In CQB (under 200yds) yes the 14.5 or 11.5 or just plain 16 does fantastic. But past 200 16 and up wins the day. 500 yards and pushing to even 800 sometimes to 1,000 your 20 inch is gonna be rocking that all day long.
The original m16 design went with 20 because at the time they wanted a rifle that could serve in most conditions of ideal combat both in close and long distance. The m16 is perfect for that. For modern combat the carbine/pistol length is the new fad. But still you can rock and roll with a long barrel.
Unless you run a short carbines with a silencer then….you got a hybrid.
Good test, as always. Thanks!
The military always get the ammo made for the most common barrel length used. Which means a full length barrel. Reason for it is muzzle flash.
Added length increases velocity in centerfire most of the time! Exception would be downloaded handloads
Dude. Pull the bullets. The a1 is significantly longer which takes up more case capacity because it contains no lead. Means more pressure to get same velocity. This is a beginners hand loading concept. Everyone said it in the comments last video too.
Yep, why would Army want to recalibrate EVERY sighting system in existence because A1 is meaningfully faster? Makes no sense.
@@vmpgsc M855A1 and M855 still have different trajectories even if they are the same velocity. M855A1 has different drag properties due to the shape of the bullet. They’re close enough out to 300m or so, but after that an optic calibrated for M855 will be off with A1.
Realistically its not going to make much of a difference. I load a max book load for one of my 7mm's with a 140gr accubond that I backed off a bit after hitting pressure and also load a 142gr copper bullet with that same load and haven't hit pressure. You can also get around hitting pressure with increased velocity by just using a different powder which is probably what the military did.
@@Nick-sx6jm Right. M855A1 just uses a faster burning powder that is optimized to fully burn out of shorter barrels. Overall pressures are similar to M855, A1 just reaches peak pressure sooner.
@@coreyp9211 For GI use, A1 preserves drops for irons and stuff like ACOGs. Using 4x BDCs at 600 meters, no one cares if the trajectories are off by a mil. The shooter is going to be vastly more of a variable than the ammo at those distances. Yes the Marines have a LPVO on their M27s but they bypassed A1 in favor of Mk318.
Literally just finished your old video and then saw you posted this!
Keep up the excellent work!
Back in the day when I was throwing the Hammer in ancient Greece I was always able to get extra distance with a few extra spins ... I still like My Winchester .243 in this day and age ! ADL Approved.
Gonna watch the original video after this. My face involuntarily scrunched up when I heard you say people thought the longer barrel was slowing down the round.
Don’t even own a gun but I’m a STEM nerd. What a ridiculous idea lmao.
Thanks for updating that video. I was always curious about that tungsten tip’s ballistic performance.
Thanks for putting the video up.
It’s not tungsten
I swear people are very dumb with this subject. A 9mm is optimized for 5". Guess what? It is faster out of a 10".
Being optimized means "it reaches an acceptable performance", not "it is the best it can possibly be".
optimized means optimized ,,so you are wrong,, but lets follow you 9mm example,, ,, if the weapon we HAVE is a 5 inch gun,, then we wants what can give us the best when used in THAT gun,, faster powder gives us a dangerous round, so its a no no, slower powder gives us a slower round,, so we use what gives us max velocity , without having to much pressure,, OR a to long pressure curve for that giving weapon,, so we end up with a 9mm load with lets say a Finnish powder like 310 or even 320,, now if we use 330, with a longer pressure curve, a 9 mm gun with a locking mechanism will be in trouble, not because to much pressure, but because of to LONG a pressure curve,, that round will be optimal for a blowback submashinegun ;o) or a blowback handgun with a rusty chamber ;o)
@@cmtwgrdk2748 bro what are you talking about
That's because the video game industry taught all of them that optimization means 'better' or 'best.' That same industry failed to teach them the actual definition of optimization, which simply put, means "most effective for [insert concept here]." Most effective *does not* always equal 'best.'
Good data. Thanks
Semper Fidelis!
A very good friend of mine who I trust, tried using Winchester green tips and he said they were constantly inaccurate because the actual steel core in the green tip (designed for penetration of basic body armor) was not always centered, which made the actual bullet spiral off creating an inaccuracy that he could never calculate from one bullet to another or from one batch to another.
"Trust, but verify." R. Regan ☆
They are trash for accuracy, why really doesn't matter at the end of the day.
In general, the more components inside a bullet of differing densities, the more likely something is slightly "off" that can affect accuracy of a bullet spinning at over 250,000 rpm. M855 and SS109 have a steel penetrator in front of the lead core, but still within the gilding-metal jacket. Lead and steel have significantly different densities. Any flaw in the shapes or alignment will put the bullet slightly out of balance. The newer M855A1 is also a three-part bullet, but the steel tip and copper "slug" are much closer in density, minimizing this issue.
The US Military requires batches of ammo to be tested to verify it meets the accuracy and pressure requirements. Some of the civilian ammo comes from batches that failed to meet the military specs. As long as it is not so far over pressure to be a safety concern, it can be sold to civilians. That is one reason that civilian M855 can be so inconsistent.
MAC I think you got the consensus wrong, nobody was saying it was slowing down the projectile (that's absurd), they were saying that the M855A1 was designed specifically to increase velocity in a *14.5* compared to M855, however you used a 18" which didn't show the strengths of the faster burning powder when in comparison.
I am glad this video was made. The legacy of the original video (with the higher pressure ammo) has been massive and I recently saw it cited to "prove" that M855A1 wrecks rifles.
As we all should know : same bullet weight. same powder weight ==== same velocity. There is only so much powder to fit the case, and keep pressure down. I have not seen anyone test the pressure of the A1, but would say -- there is no extra 10000 psi as said to have. The ballistic gel looks better, but the actual use of the round is to penetrate. Goose or Gander ............. Nice video and great work. Salute
it's not just barrel length, it's twist and bullet stability in flight. Great video!
Great information and thank you!
Appreciate the statements you n older vs current M855A1
The only difference between the M855 and the M855 A1 is the former was designed for a 20” barrel with a 1 in 9 twist and the boat tail is lead filled. The A1 was redesigned for the shorter barrels in service now with increased case pressure and the projectile has zero lead behind the steel tip. The original M855 has better ballistics out of a 20” barrel than the A1 so it really depends on what you’re shooting with for MOA and velocity.
Thank you Tim for the video.
I think the velocity similarities would make a lot of sense in a military setting, since you already have tons of optics with BDCs and reticles designed for the original M855. A difference in velocity would likely mess all of those up.
The M855A1 bullet is longer than the M855 bullet, so there should be less powder in the case of the M855A1. The higher pressure would be pushing the same weight bullet, to the same velocity, on a lower powder charge.
Thanks, guys. Another quality video for the doubting Thomas's.
If you have time, I would love to see a comparison between 69gr, 75gr, and 77gr out of a 14.5.
I've been using BTHP 69gr for varmint hunting here at farm, but I keep hearing that I should switch to one of the others for better performance all around. Thanks
I'm appreciating this. I like your set up. You are detailed, knowledgeable, and practical. Although why buy surplus ammo. I got some green tip, yet it is by far the most dirty bullets put through my rifle. Rounds are waterproof...cool. Yet super sludge in the rifle. Aguila to be specific. Sig ammo and Black Hills have been my go-to. I don't always buy match grade, but I for sure can see the delta in keeping a clean rifle paired with higher quality. Every round counts in practice. Why dirty up a rifle? Do you see this with that surplus or old school green tip? So much factors in here. Temp, gear, the shooter, position, altitude, day or night. ..No negativity bro. I appreciate your channel. How would all the ammo in each rifle react after 7 to 9 mags?
I think the lower velocity is due to the loading.
I remember reading in the past that military ammo isn't supposed to be sold to civilians, so they pull the bullets, then sell the components separately.
Back when m855 first came out, you could ONLY buy it this way. Basically reloads, but they used lake city brass and real m855 bullets + off the shelf powder.
You'll notice that normal military ammo you buy is xm855 or xm193, and x means it never made it to the military, so it's ok to sell to you.
Thanks
That's a cool app on your phone for velocity readings!👍
Evaluating ejection averages between the two ammunitions from the same rifle would go a long way to determining pressure differences between the cartridges
As you say, the M855A1 is hard to find and expensive. Seems like a no brainer. Thanks for the good video.
Get friends in the military. I had a friend who would smuggle me a few rounds out every drill he went to. I never paid a dime for them. I still have 30rds.
Join the army, gear adrift is gear a gift :)
Longer barrel = more velocity. Cutting down a long barrel drops velocity about 50 feet per inch cut off.
I remember back when M855A1 first came out, or not long after it came out, someone on ARF got a few rounds (maybe they had some projectiles and reloaded them, but it was a long time ago) and did ballistic gel testing and posted the results. The Pentagon contacted Edward (not Ed Sr) and asked him to remove it. That made me want some, when before hearing that, I had no real interest in it at all. I still have never had or shot any though. I always thought, "It must be pretty damned good if The Pentagon wanted gel testing footage removed from the internet." I guess they never heard of the Streisand Effect or that the internet is forever. Anyway this reminded me of that.
Thank you
Very low power, low powder capacity cartridges do suffer from slower velocities in longer barrels. Ex: 22LR is optimal in a 16" barrel, any longer than that velocities start decreasing. On the flip side most center fire rifle cartridges benefit from longer barrels(within reason), ex: most F-class shooters use barrels between 30-32" some even up to 36" as they get higher velocities with the same powder charge and their bullets drop less because of the higher velocity and shorter flight times.
Love the flex with a belt-fed pull of a round
M855 or 62 grain green tip was designed for the 20" barrel in mind, you'll get best performance out of a 20" with milspec ammo or almost any other ammo for that matter. Through my own personal tests, it performs much better in the 20". I also reload .223/5.56. I've never heard such nonsense.
From my testing... The shape of a bullet has more to do with the damage that a bullet will do rather than the velocity that the same bullet is pushed down range at! Again, in my tests, a 55 grain FMJ 5.56mm bullet moving at 3050 fps will punch through a level 3A plate out to 35 yards, where as a 62 grain "penetrator" moving at 3200 fps, will not punch through the same plate at 10 yards! Further, the most damaging hits observed on AR-500 steel plates at 50 yards came from round nosed exposed lead tipped bullets, (30-30 type bullets) not 30 caliber spitzer's, hollow point's, or even .30 cal A.P. bullets, all leaving the tube at similar velocities! IMHO: bullet shape has been the determining factor in the amount of damage on AR-500 steel as well as level IIIa steel plate rather than velocity alone! Your thought's/observations and or test results???
still sold on a AR-15A2 20" over a shorter milspec 14.5, only reason I have 16" carbines is for house use.
Always enjoy your site over the years Semper Fi.
"optimized" barrel lengths mean nothing like this. Just means that all powder is meant to be burned by that length, pressure still builds and velocity still increases, just not as much as if it wasnt burning all powder
I was given these when I was in Afghanistan in 2011-2012, i have a photo of it on my album.
As we saw from demolition ranch's stupidly long barrel videos.. it takes a lot of barrel to actually decrease velocity. You just get diminishing returns after a specific point.
Probably back in the 90s Handloader/Rifle magazine took up the issue of barrel length. Even with the 22LR the barrel has to be very, very long before it starts to slow down a bullet. You couldn’t likely never see a rifle barrel long enough to slow down a standard rifle cartridge.
Could you make a specialty handload where this occurs? Sure. Maybe some specialty subsonic ammo would eventually slow down too.
,22lr does slow down in long factory barrels,, ALL target riffles slows down the bullet,(target ammo) , i had a longbarrelede Marlin lever action, with target ammo, i thought a had a squib load,, not so, the powder just burs out,, that helps accuracy ,, if you can find it, there are test of the Ruger 10/22 , they wanted to see what barrel lngh was best for suppressor, a short barrel compared to stock, was faster, with target ammo, and broke the sound barrier,, with bulk cheap hig velocity, the short barrels was slower,, so it did depend on what ammo you planned on using,
Thanks, good info.
I had that same braclet when I was in middle school. I made it out of a dirtbike chain.
Looking at that would suggest the m855a1 is made to be more uniform for use in a shorter barrel.
Ie m855 in the longer barrel has closer velocity where the a1 has a wider spread.
The shorter barrel is the opposite so a1 has smaller deviation in velocity where 855 is a bigger spread.
Couple that with better bullet damage of the a1 would say its better for military use in warfare?
I need one of those chronos...keep putting off getting one. Need to stoppit. Looks awesome.
Good stuff. Thanks
Informative video! Question though, is the twist on all three barrels the same? I have heard that a "greater twist" barrel is a little shower than a barrel with less twist (AKA. 1:7 vs 1:9). No claim of expertise coming from my end just curious is all. Kind regards.
From my understanding solid copper is slower because the bullet doesn't conform to the same degree that the softer lead core does to the inside of the barrel. Less of a seal, less pressure, less velocity.
Well done. Thank you.
The military always has ammo made for the most common barrel length of the M16. Which is full length. The shorter barrels are for special units. The shorter the barrel the bigger the muzzle flash. Not good in low light or night.
You have the “spicy” M855A1! The headstamp on the one you showed was 2014! 2012-2018 were the higher pressure loads.
No they weren't. It was before LC11
Obviously, you can carry things too far. But normally a longer barrel will give a little more velocity, because even if the powder is totally burnt at 9", there is still tremendous pressure in the barrel until the bullet exits the barrel. The barrel has to be ridiculously long before gas expansion weakens enough to start slowing the bullet.
Even pistol rounds exit at higher speeds when shot out of a carbine or rifle.
1st hand accounts of the M855A1 in theater from people I trust have called it "The Hand of God" and claim it kept the 5.56 platform from being completely overhauled. The ability to carry a lot of 5.56 over other larger calibers is very advantageous for most infantry troops.
Go look at my comments on small arms solutions under this moniker. In “section 8 post”.The posts I made are many.
Keep in mind that, although they say this is a replacement for the m4, m855a1 is a tack hammer, .277 is a framing hammer, .338 is a 9 lb hammer. The ballistics of the .277, does in shorty config , the job of a 16” m855a1 with almost twice the energy.
The shortfall of the 308 is its inability to have high b.c. And 2575-3100 fps. Period end of story.
Over time through innovation the m7 will fit your present criteria (your weight requirements). And ammo might go lightweight steal on plastic.
The .277 competitor is the 7.62 x 39 and .277 cleans house.
The competitor for the m855a1 is 7.62 x 39 and m855a1 cleans house
The 7.62 x 39 cannot go 3100fps whilst boasting a relatively high b.c.
The headroom created is rarified air/the zone between 3100fps and 2575fos is where they must operate to cut steal. Short TOF/Speed accumulates a multitude of benefits.
Little know fact.
Chaps, listen up…..
If you can get MSR fusion either as orange box or
White box fed factory overrun.
You will get a 62 gr bonded sp that does 2800 cos out of a 11.5
And 2950fps out of a 14.5”
Yes, that the same speed therefore its logical to conclude someone might have leaked or guessed the m855a1 charge.
No friggin brainer.
Hogs check
Deer check
Defensive black bear…. Emmmmm that’s an emergency case
I don't think anyone was saying that. People were saying that a1 had a sooner pressure spike than regular. Remember when you shot 9mm and 357 from a 2" revolver and the 9mm had 100ftlbs more energy? Same sort of situation
If I was to send in a 16 inch one by 8 inch twist barrel to you. Do you have enough of the new ammo to get a look at how much into roads to barrel?
Did they actually reduce the pressures? That explains the lower velocities of your test. It would be fun if you found older ammo loaded to the higher pressures. Weren't they initially trying to get over 3000fps out of a 14.5?
I wonder if the a1 has a longer bullet to get the weight, since it doesn't have lead, and thus has more friction in the barrel, thus needing higher pressures to achieve the same velocity?
Seems crazy you had to make a video based on this weird theory. There was enough hints before hand to show it was overgassed to begin with. Gas equals speed which means there is not enough barrel to get 100% burn whether you wanted it or not. The theory is only relevant in this case if the barrel is a unrealistic length
Solid!
Top KEK!
Peace be with you.
Current body armor theory is that you can survive the gut shot by getting to a hospital fast enough.
Remove immediate medical care and the 8x10 armor plate means a lot less.
a shorter barrel cannot produce a faster velocity, physics says so. Adding a suppressor also increases velocity.
My guess is lake city doesn't change the recipe between m193, m855, and m855a1 now. Just using different projectiles depending on the run.
That is 100% false. Each bullet will produce different pressures with the same powder load.
was that a '14 year stamp on the m855a1 case head? - after some googling, the m855a1 started as early as 2010, much earlier than i thought.
I think the argument was more that the powder burned quicker, resulting in higher pressure, thus comparing 855 vs 855A1 in a 14.5 would have resulted in a larger advantage to A1, vs comparing them in a longer barrel. I think the conclusion is that the pressures aren't actually different. There may have been some people claiming that the extra barrel length was slowing the round down, but that's kind of a straw man. It's easy to find people making stupid arguments - there were plenty of people mentioning the higher pressure round should have a larger advantage in a shorter barrel.