M855A1 SBR gel test

[Andrew Wiggin]

http://www.youtube.com/watch?v=clZwnSQnfH8

https://youtu.be/clZwnSQnfH8

The Army's new M855A1 62 gr EPR fired from 11.5" AR into calibrated 10% ordnance gelatin.

If anyone knows the BC for this projectile, please post so we can correlate this to approximate down range performance for longer barrels.

[Jeep]

Andrew: Another nice test--it looks like a pretty effective bullet (which it should be considering how much in damages the Army is going to have to pay for stealing it!)

[Andrew Wiggin]

Lol, right. Here's hoping that Liberty either starts producing out for the civilian market or licenses another company to do same.

[rauchman]

Cool stuff. I understand these rounds are known for being "hot". Did you happen to notice higher recoil than a standard M855 round?

Thanks for the vid's.

[Andrew Wiggin]

No noticeable difference in recoil. The original run was supposedly very hot. More recent production has been loaded to more reasonable levels.

[Drang]

If anyone knows the BC for this projectile, please post so we can correlate this to approximate down range performance for longer barrels.
Hmmm:
Improved Performance M855A1 Ammunition (http://www.gdiengineering.com/wordpress/2012/03/28/improved-performance-m855a1-ammunition/)

Due to the elimination of lead from the projectile, and its subsequent replacement with less-dense copper and steel, the new M855A1 projectile has an increased ballistic coefficient – although ARDEC doesn’t specify what that is.
Interestingly, when I started typing "ballistic coefficient m..." into the search engine it offered me "ballistic coefficient M193 M855 M2..."

Anyway, according to ShootersCalculator.com | Ballistic Trajectory Calculator (http://www.shooterscalculator.com/ballistic-trajectory-chart.php?t=f13e8e2b) the M885A1 round has a BC of .371. I make no claim to know where they got that, or if it's accurate.

[Andrew Wiggin]

great post. Thanks for doing the research.

[Unobtanium]

As more and more information comes to light on M855A1, it is looking more and more like a VERY GOOD round. I have literally NEVER heard anyone who has used it say otherwise. Everyone I know who kills people for a living, and has used it, has given it glowing reports. Through cars. Through people. It just seems to WORK. The initial issues all seem to have been worked out, and it is only wearing guns out faster by the small amount that the pressure was bumped over M855, which, as many will recall, was a bump over M193, and resulted in similar wear. I am curious why there was so much opposition to M855A1 from so vocal an aspect of the community. I understand it had fleas when it began, but as they have been worked out, that contingent has fallen silent, amid reports of how bloody effective it is. I just find the political maneuvering...odd. I am glad that our troops have better tools!

[Sixgun_Symphony]

No noticeable difference in recoil. The original run was supposedly very hot. More recent production has been loaded to more reasonable levels.

I shot some of the 2011 stuff while deployed to Afghanistan and it was noticeably harsher in recoil from an M4.



As more and more information comes to light on M855A1, it is looking more and more like a VERY GOOD round. I have literally NEVER heard anyone who has used it say otherwise. Everyone I know who kills people for a living, and has used it, has given it glowing reports. Through cars. Through people. It just seems to WORK. The initial issues all seem to have been worked out, and it is only wearing guns out faster by the small amount that the pressure was bumped over M855, which, as many will recall, was a bump over M193, and resulted in similar wear. I am curious why there was so much opposition to M855A1 from so vocal an aspect of the community. I understand it had fleas when it began, but as they have been worked out, that contingent has fallen silent, amid reports of how bloody effective it is. I just find the political maneuvering...odd. I am glad that our troops have better tools!


I'll keep this short and somewhat coherent. Pros and cons with the M855A1 (early lots) in my experience. IMO it con'd more than it pro'd. Good accuracy, and it definitely put bad guys down harder than the green tip and I got to see a few of these from both projectiles. But we definitely had some serious increase in wear on the M4's and at least one broken bolt (as much as I'd like to completely blame it on the EPR, it was likely only aggravated to that point). Thru cars doors and glass...I was HIGHLY unimpressed, it did tear up wood structures/defenses nicely.

M855A1 in the M249, we noticed a pretty significant increased wear & tear on parts, a slight increase in the rate of malfunctions. Our PLT continued to use a mix of M855, M995 depending on mission needs. Despite the increased terminal effectiveness and "barrier" penetration capabilities of M855A1. Reliability of the SAW was the number one requirement. I wouldnt call it a glowing report whatsoever. It was ok...

[Wayne Dobbs]

This load is tearing up guns. The average chamber pressure is ~65K PSI and is causing much faster bolt and barrel wear in TDP compliant M4s. It's completely UNSAFE in guns without NATO chambers, such as Bushmasters, DPMS, etc. And no, Muffy, you can't trust the barrel rollmark about what chamber you have. On these guns, there have already been catastrophic failures. The steel nose cone is eroding the receiver feed ramps and projecting said aluminum shavings into chambers and bores. All bad stuff. The most vexing thing about this thread is where did you legally obtain any of this ammo, since it is not available in commercial channels??

[DocGKR]

Concur with the comments by Sixgun_Symphony and Wayne Dobbs. The terminal performance illustrated in the video linked at the top of this thread is NOT ideal. It is clear that the M855A1 depicted in the video suffers in comparison to other common defensive loads like TBBC, Gold Dot, TSX, or even Mk318--if you can't figure out why that bi-lobed yaw cycle is lacking, you might wish to review this: https://pistol-forum.com/showthread.php?4333-Ordnance-gelatin-test-assessment-for-rifle-and-pistol-calibers. Also look carefully at the recovered projectile...

[Unobtanium]

-Chamber pressure on current m855a1 is less than m855, at 54k and change. 25.5gr of smp-842 +- 0.2gr or so.

-It penetrates hard stuff like a boss.

-I am unsure how it compares to mk318, but I defer to Dr Roberts on that. The current range at which it frags reliably is 450 yards from an m4.

I think the political maneuvering, patent theft, and other wastes of time and taxpayer money are disgusting, but the end product seems like a great one, overall.

I saw some of liberty's testing on the t3 projectile, and while the steel penetrator veered bad after hitting a windshield, the slug behind tracked true in gel behind it. The cu slug is roughly analogous to mk318s base.

At what distance does mk318 reliably fragment?

I think the army skewed a1 to hard barrier performance and the usmc, mk318 to soft tissue performance. Also, as to the bilobular wound tract, I think this is variable. It is produced by the cu slug and iron penetrator tumbling, which seem to be variable, I'd guess.

Anyway, that's my take on it with a bit of additional data.

[Unobtanium]

This load is tearing up guns. The average chamber pressure is ~65K PSI and is causing much faster bolt and barrel wear in TDP compliant M4s. It's completely UNSAFE in guns without NATO chambers, such as Bushmasters, DPMS, etc. And no, Muffy, you can't trust the barrel rollmark about what chamber you have. On these guns, there have already been catastrophic failures. The steel nose cone is eroding the receiver feed ramps and projecting said aluminum shavings into chambers and bores. All bad stuff. The most vexing thing about this thread is where did you legally obtain any of this ammo, since it is not available in commercial channels??

The feed ramp and chamber face damage has been all but eliminated with pmags. The only issue is with mk18s when suppressed, and even that is just cosmetic in severity.


The ammo is all over gunbroker I thought? Also, some companies sold just the projectiles a while back.

[Sigfan26]

-Chamber pressure on current m855a1 is less than m855, at 54k and change. 25.5gr of smp-842 +- 0.2gr or so.

-It penetrates hard stuff like a boss.

-I am unsure how it compares to mk318, but I defer to Dr Roberts on that. The current range at which it frags reliably is 450 yards from an m4.

I think the political maneuvering, patent theft, and other wastes of time and taxpayer money are disgusting, but the end product seems like a great one, overall.

I saw some of liberty's testing on the t3 projectile, and while the steel penetrator veered bad after hitting a windshield, the slug behind tracked true in gel behind it. The cu slug is roughly analogous to mk318s base.

At what distance does mk318 reliably fragment?

I think the army skewed a1 to hard barrier performance and the usmc, mk318 to soft tissue performance. Also, as to the bilobular wound tract, I think this is variable. It is produced by the cu slug and iron penetrator tumbling, which seem to be variable, I'd guess.

Anyway, that's my take on it with a bit of additional data.


The feed ramp and chamber face damage has been all but eliminated with pmags. The only issue is with mk18s when suppressed, and even that is just cosmetic in severity.


The ammo is all over gunbroker I thought? Also, some companies sold just the projectiles a while back.

Not trying to derail, but I am curios on where this info is from, as DocGKR has supported the above statements (and is the resident SME)


Sent from my iPhone using Tapatalk

[Sixgun_Symphony]

-Chamber pressure on current m855a1 is less than m855, at 54k and change. 25.5gr of smp-842 +- 0.2gr or so.

-It penetrates hard stuff like a boss.


Anyway, that's my take on it with a bit of additional data.

I had heard the chamber pressure had been reduced..But less than M855?

All that penetration didn't mean a whole lot with the amount of deviation we had (after barrier effects), when my unit could source Mk318..we did, and it was much more appreciated.


The feed ramp and chamber face damage has been all but eliminated with pmags. The only issue is with mk18s when suppressed, and even that is just cosmetic in severity.


The ammo is all over gunbroker I thought? Also, some companies sold just the projectiles a while back.

Most Soldiers in my Bn used PMAGS and NOT USGI generally speaking.... Feed ramp and chamber face wear was certainly NOT eliminated (or even remotely close)...We even experience stove pipes with pretty obvious indication it was ammo related. The M249 had even more issues with the ammo. Doc I've read all your comments on M855A1 and agree with everything based on personal experience with the load. Except with when you said it would make a good GP LMG load..the M249 had such an increased rate of failures that I wouldnt touch it.

[Unobtanium]

I had heard the chamber pressure had been reduced..But less than M855?

All that penetration didn't mean a whole lot with the amount of deviation we had (after barrier effects), when my unit could source Mk318..we did, and it was much more appreciated.



Most Soldiers in my Bn used PMAGS and NOT USGI generally speaking.... Feed ramp and chamber face wear was certainly NOT eliminated (or even remotely close)...We even experience stove pipes with pretty obvious indication it was ammo related. The M249 had even more issues with the ammo. Doc I've read all your comments on M855A1 and agree with everything based on personal experience with the load. Except with when you said it would make a good GP LMG load..the M249 had such an increased rate of failures that I wouldnt touch it.

Were they before Gen 3 pmags? If so, the feed lip orientation was not as good as pmags Gen 3. The only government tests I am aware of indicate that pmags fix the issue until well beyond useful barrel life.

I cannot vouch for the person who shared the load data for me, but I can vouch for the velocity. They are clocking around 30 to 50fps faster than m855 from the same gun on the same day. I will have to tear down a few rounds to verify the 25.5gr charge weight, and if accurate, will in my mind add even more weight to the statements made to me about pressure, etc. as I have to way to measure that, and simply must take what I am told there.

Back when you indicate you were issued m855a1, it was clocking 3150ish out of a 14.5 and was indeed hot as hell, and I and the Army, apparently, agree with you, and it was softened up at the expense of terminal performance at distance somewhat.

[Unobtanium]

Not trying to derail, but I am curios on where this info is from, as DocGKR has supported the above statements (and is the resident SME)


Sent from my iPhone using Tapatalk

It comes from various sources. Some I trust implicitly, some I can only say agree with my personal observations and so I take the things I cannot observe (pressure values) at face value since the rest of the data that I CAN observe matches. Without very expensive lab equipment, it's what I got. I plan to weight out a few charges and see.

[Andrew Wiggin]

This load is tearing up guns. The average chamber pressure is ~65K PSI and is causing much faster bolt and barrel wear in TDP compliant M4s. It's completely UNSAFE in guns without NATO chambers, such as Bushmasters, DPMS, etc. And no, Muffy, you can't trust the barrel rollmark about what chamber you have. On these guns, there have already been catastrophic failures. The steel nose cone is eroding the receiver feed ramps and projecting said aluminum shavings into chambers and bores. All bad stuff. The most vexing thing about this thread is where did you legally obtain any of this ammo, since it is not available in commercial channels??


It has been available from time to time.

[Wayne Dobbs]

It has been available from time to time.

Where?

[Wayne Dobbs]

Were they before Gen 3 pmags? If so, the feed lip orientation was not as good as pmags Gen 3. The only government tests I am aware of indicate that pmags fix the issue until well beyond useful barrel life.

I cannot vouch for the person who shared the load data for me, but I can vouch for the velocity. They are clocking around 30 to 50fps faster than m855 from the same gun on the same day. I will have to tear down a few rounds to verify the 25.5gr charge weight, and if accurate, will in my mind add even more weight to the statements made to me about pressure, etc. as I have to way to measure that, and simply must take what I am told there.

Back when you indicate you were issued m855a1, it was clocking 3150ish out of a 14.5 and was indeed hot as hell, and I and the Army, apparently, agree with you, and it was softened up at the expense of terminal performance at distance somewhat.

PMAGs can certainly be used in an M249 on an emergency basis, but since it's a belt fed, it prefers...well, a belt! The Aberdeen Proving Grounds document I have indicates the A1 round is loaded to a "higher chamber pressure" than M855, so it's definitely not lower than M855 and if it is then there's no way, Newtonian Laws still holding, that it can have higher velocity than M855 with a lower chamber pressure and the same mass of projectile. I don't care if we wear out M4 bolts and barrels 25% faster (field reports), but I do care if the standard poorly informed shooter loads this in his hobby grade carbine and high orders it. Don't buy this stuff, don't accept this load and don't use this load CONUS. Its juice ain't worth the squeeze.

[Andrew Wiggin]

American Reloading had M80A1 and M855A1 projectiles for sale. Gun Broker routinely has M855A1 loaded ammo for sale.

[Andrew Wiggin]

PMAGs can certainly be used in an M249 on an emergency basis, but since it's a belt fed, it prefers...well, a belt! The Aberdeen Proving Grounds document I have indicates the A1 round is loaded to a "higher chamber pressure" than M855, so it's definitely not lower than M855 and if it is then there's no way, Newtonian Laws still holding, that it can have higher velocity than M855 with a lower chamber pressure and the same mass of projectile. I don't care if we wear out M4 bolts and barrels 25% faster (field reports), but I do care if the standard poorly informed shooter loads this in his hobby grade carbine and high orders it. Don't buy this stuff, don't accept this load and don't use this load CONUS. Its juice ain't worth the squeeze.


This part is not necessarily correct. A slower powder can produce higher velocity with lower peak pressure. I'm not saying that's the case here, but it's not a violation of the laws of physics for lower chamber pressure to still produce higher velocity.

[Unobtanium]

PMAGs can certainly be used in an M249 on an emergency basis, but since it's a belt fed, it prefers...well, a belt! The Aberdeen Proving Grounds document I have indicates the A1 round is loaded to a "higher chamber pressure" than M855, so it's definitely not lower than M855 and if it is then there's no way, Newtonian Laws still holding, that it can have higher velocity than M855 with a lower chamber pressure and the same mass of projectile. I don't care if we wear out M4 bolts and barrels 25% faster (field reports), but I do care if the standard poorly informed shooter loads this in his hobby grade carbine and high orders it. Don't buy this stuff, don't accept this load and don't use this load CONUS. Its juice ain't worth the squeeze.

Yes, it can. It depends on pressure curves and average pressure over time, etc. etc. etc. It is loaded 800psi short of M855, currently. There are reloading forums out there with guys using similar charge weights of commercially available SMP-842 and getting identical velocities, safely.

Here ya go:

http://www.tngunowners.com/forums/topic/49004-smp-842/

Primed lake city brass

62 grain SS 109

Crimped

16" AR15

25.7=~3,045

25.8=~3,070

25.9=~3,095

This is in my gun. I assume no responsibility in the data I just posted in your firearm.

Dolomite

His numbers are showing a touch more velocity than the M855A1 factory ammo shows. And he's not complaining about flattened primers or blown primers...He is using a 16" 1/9 twist AR...so you tell me the odds of it being a "spec" gun...Anyway, his final load, if you read the thread, for a 62gr bullet is 25.8gr. Roughly 0.3gr more than M855A1. And he arrived at that number all by himself, it seems, through looking at his brass and the chrony.

In fact, people are RAVING about how accurate and awesome it is. Wear and tear just isn't an issue with the current loading beyond the bores seeing similar reduction in barrel life as other advancements (M855, 70gr TSX, etc.). The parts maintenance schedule has not changed.

Oh, and as an FYI, Liberty's patent information was a bit loose, and a Federal Court overturned the ruling to favor the government. Liberty lost the appeal. I do not know what that means financially for both parties, exactly, or the US tax payer, nor do I feel that this morally exonerates the US government, but it is what it is. This is why you get a GOOD patent attorney...

[Chuck Haggard]

Since when was the P-Mag reauthorized for use by the Army?

[Erick Gelhaus]

Regarding using magazines, regardless of who made them, in a M249 there is the need to double spring them. I ire, this is get/keep that rate at which the magazine feeds consistent with the speed of weapon cycling. While I imagine that would apply to pats I am unable to offer any opinion since I never used a page in a SAW.

[Unobtanium]

Regarding using magazines, regardless of who made them, in a M249 there is the need to double spring them. I ire, this is get/keep that rate at which the magazine feeds consistent with the speed of weapon cycling. While I imagine that would apply to pats I am unable to offer any opinion since I never used a page in a SAW.

Nor am I advocating that. I know nothing about the saw, or how m855a1 interacts with it, but I see no point feeding a beltfed from a mag to use some special bullet.

[Sixgun_Symphony]

Since when was the P-Mag reauthorized for use by the Army?

I can very, very vaguely remember the Army restructing use of the PMAGs now. But I can tell you that no unit (Infantry) I was in ever enforced it whatsoever, and pmag by and large had been very common and popular among rifleman.


Were they before Gen 3 pmags? If so, the feed lip orientation was not as good as pmags Gen 3. The only government tests I am aware of indicate that pmags fix the issue until well beyond useful barrel life.

I cannot vouch for the person who shared the load data for me, but I can vouch for the velocity. They are clocking around 30 to 50fps faster than m855 from the same gun on the same day. I will have to tear down a few rounds to verify the 25.5gr charge weight, and if accurate, will in my mind add even more weight to the statements made to me about pressure, etc. as I have to way to measure that, and simply must take what I am told there.

Back when you indicate you were issued m855a1, it was clocking 3150ish out of a 14.5 and was indeed hot as hell, and I and the Army, apparently, agree with you, and it was softened up at the expense of terminal performance at distance somewhat.

Likely before Gen III


PMAGs can certainly be used in an M249 on an emergency basis, but since it's a belt fed, it prefers...well, a belt! The Aberdeen Proving Grounds document I have indicates the A1 round is loaded to a "higher chamber pressure" than M855, so it's definitely not lower than M855 and if it is then there's no way, Newtonian Laws still holding, that it can have higher velocity than M855 with a lower chamber pressure and the same mass of projectile. I don't care if we wear out M4 bolts and barrels 25% faster (field reports), but I do care if the standard poorly informed shooter loads this in his hobby grade carbine and high orders it. Don't buy this stuff, don't accept this load and don't use this load CONUS. Its juice ain't worth the squeeze.

Wanted to make a note on the M249/M855A1 ... we linked the ammo (and in NO small quantity either! ... Both for testing and possible use in the field) and got the issues I spoke briefly about..Dont recall ever shooting it from a magazine in the SAW.

[Unobtanium]

I can very, very vaguely remember the Army restructing use of the PMAGs now. But I can tell you that no unit (Infantry) I was in ever enforced it whatsoever, and pmag by and large had been very common and popular among rifleman.



Likely before Gen III



Wanted to make a note on the M249/M855A1 ... we linked the ammo (and in NO small quantity either! ... Both for testing and possible use in the field) and got the issues I spoke briefly about..Dont recall ever shooting it from a magazine in the SAW.

I believe around 2009 was when the feed-lip angle for the PMAG was improved to the point that M855A1 should work well from it. However, also note that you may well have been using abusively hot M855A1. I don't know what powder charge the ammo you had was loaded to.

[HCM]

Since when was the P-Mag reauthorized for use by the Army?

AFAIK it was only the USMC which prohibited PMAGS due to the compatibility issues with the M27 IAR /HK 416 magwell and gen 1/2 PMags.

[Unobtanium]

I finally got around to doing some accuracy testing.
Averaging a total of (9) 10 shot groups fired over the span of 2 days, I arrived at 3.59 MOA.
The best group measured 2.07 MOA
The worst group measured 4.707 MOA.

Interestingly, the first groups of the day which were fired with M855A1 (which would be the second total group fired, on Day 1, so NOT the first group total, fired of any day), showed the best precision on both days.

I followed my typical procedure as regards to loading, resting the rifle, and barrel-heat (I let mirage off the suppressor be my quide) as to which I have followed in the past, which has typically produced 1.5-2.0MOA from ammo the rifle likes.