New U.S. Military Bullet Partially Revealed

[Guest TnRebel]

New U.S. Military Bullet Partially Revealed

New U.S. Military Bullet Partially Revealed

5/16/2011

The U.S. military is soon to field a new projectile in its standard issue 5.56 mm NATO cartridge. There are two purposes to the new projectile: increased performance and less toxicity in the environment (i.e., lead-free).

The new round is designated as the M855A1 and it shares identical weight and velocity to the current M855, 62-grain bullet at around 3,100 fps. The difference is the bullet’s construction, which while similar, is changed from the steel-shank, lead-core, copper-jacketed SS109 projectile of the M855 round.

The new A1 projectile is also tipped with a steel penetrator, but unlike the SS109, the steel tip is bronze coated to prevent corrosion (instead of being painted green) and features a more aerodynamic shape that called a “steel arrow head.â€

Instead of a lead core behind the steel tip, the A1 projectile features a solid copper core. The copper jacket that encases both the cooper core and the “steel arrow†is of an unusual design with a “reverse drawn†process.

As we know from the Insider’s favorite hunting bullet, the Barnes X, a solid copper bullet of the same weight as a lead core bullet is going to be longer since lead is denser than copper. That’s true with the A1 bullet as well, although the Picatinny Arsenal which developed the M855A1 has not yet divulged specific details like the bullet’s length, ballistic coefficient or sectional density. Picatinny does, however, note that the M855A1 has a higher chamber pressure than M855, but does not provide a number.

In a prepared statement, the Dept. of Defense described the evolution of the new round:

“In post-combat surveys and field reports from Iraq and Afghanistan, most soldiers have indicated that the (M855) works fine, delivering the desired effects against threat targets. But some soldiers have reported that the round did not perform consistently, causing concern in the ammunition community.

“In parallel, mounting environmental concerns drove the Army to consider replacing environmentally unfriendly materials such as lead. The Army's ammunition community, led by PEO Ammo, saw an opportunity to address the two concerns associated with the M855 round—lead and consistency.

“The Army's solution is the new M855A1 Enhanced Performance Round (EPR). This round offers better performance than the M855 against all targets likely to be engaged with small arms. This is quite a feat, considering the long-standing solid performance of the M855.â€

The Insider is trying to procure a box of M855A1, but this will be tricky. When Colt engineers were invited to the Aberdeen Proving Grounds to test fire the new round in the Colt M4, they were told in no uncertain terms that the removal of a single cartridge, or even a spent casing, would result in criminal prosecution—no exceptions.

I was in the Colt factory earlier this week and Colt, even as a military contractor for the M4 rifle, still does not have any M855A1 for test firing.

If I come up with any… mum’s the word.

[William_Munny]

Another decision by a commission... the 5.56 never was an effective round.

Anything less than a .30 cal is no good... they should just stick to the .308...

[flyanything]

6.8 is good also. Size,Kinetic energy, Weight. Kind of a in between of the 7.62 and 5.56. I agree about the 5.56. It's kind of like a video game where people get shot several times before going down. With 6.8 or 7.62, they're down.

[Caster]

Oh this is certainly a decision made by idiots. Copper is what around $3 a lb for scrap??? Lead is still cheap. How much will these cost? The military don't care, but the tax payer does. Ammo prices (tax payers bill) will triple or more and the military will still burn, shoot or give away left ammo by the tens of thousands of round cause it's supposedly cheaper than loading it up and bringing back home.

Gee, I don't have a clue why the US is broke.

[eapking]

How chic.

[Dolomite_supafly]

This has been hashed out plenty of times before.

The military ruined the cartridge by increasing the twist and using heavier bullets. The heavier bullets require the velocity to be reduced this reduces the chance the bullet will disrupt on impact and the increased twist decreases the likelyhood of the bullet tumbling upon impact. Believe it or not but by taking the 5.56 and reducing the velocity to less than 2000 fps it will increase its penetration because the bullet no longer tumbles or disrupts on impact. This is the reason we are hearing of all the problems with it overseas. The military is trying to take a short to medium range caliber and turn it into a long range caliber.

Here are some interesting reads on the effectiveness of the 5.56 you have seen before:

Do not hot link this but copy and paste it into a new browser to open it:

http://stevespages.com/pdf/5_56mm_military_info.pdf

This is the penetration based on velocity:

http://stevespages.com/jpg/bestbullet.jpg

To fix the problem the military needs to slow the twist down to get the bullet on the edge of stability so it tumbles upon impact or increase the velocity of the bullet so it falls apart upon impact. Right now the heavy bullets out of a 7 twist barrel do neither at any range beyond QCB distances. Adding barrel length would help some. This is why you don't hear as many reports of problems from the Marines because they are still using 20" guns which increase velocity. I would also venture a guess that the barrels they are using are 9 twist rather than 7.

The original design called for a 12 twist barrel firing a 55 grain bullet. The Miller formula, which is used to determine stability, was 1.42 which according to the experts was perfect. If the military insists on using these bullets they need to go back to at least a 9 twist barrel and maybe even a 10 or 11 twist. That way the bullets are stabile enough for flight but tumble immediately upon impact. I shoot 69 grain bullets with a 9 twist barrel and have no issues with keyholing. I literally have hundreds of rounds without a single incident of the bullet not being stabile. With that being said there is no reason to have a 7 twist barrel for a lighter bullet that is definitely not longer than the 69 SMK I use. Another thing to consider is the size of the target personell. They are barely 8 inches thick and with the heavier, faster spinning rounds the bullet exits the body before it tumbles or disrupts.

Just my thoughts on this. I am no expert but I have done a lot of testing on twist rates when I was trying to get subsonic bullets to tumble. If I can get a bullet travelling at 1050 fps to reliably tumble in 6" of water then there shouldn't be a problem getting a 2500 fps bullet to do the same providing the twist is the correct one for the bullet ebing used.

Dolomite

[Gandalf]

Dolomite,

I just want to say I really enjoy reading all your posts. Your are a very informed shooter and I can tell you have the experience to back up what you say. You may not claim to be an expert, but you are as close to one as I have ever seen. Thanks!

[Dolomite_supafly]

Thanks.

We just need to realize that the 5.56 was never intended or designed to do what they are try to get it to do now. If they are going to keep using the 5.56 they need to go back to the original specs then design a new long range caliber. That is if they feel the 308 doesn't fill the role. Personally something in 6.5mm-7mm would be a better choice than 7.62 in it's current state. 7mm-08 would be better ballistically as well as lighter to carry and give terminal performance at least as equal to the 308. And doing a service wide swap from 308 to 7mm-08 would be nothing more than a barrel swap in most cases.

Dolomite

[vontar]

Oh this is certainly a decision made by idiots. Copper is what around $3 a lb for scrap??? Lead is still cheap. How much will these cost? The military don't care, but the tax payer does. Ammo prices (tax payers bill) will triple or more and the military will still burn, shoot or give away left ammo by the tens of thousands of round cause it's supposedly cheaper than loading it up and bringing back home.

Gee, I don't have a clue why the US is broke.

plus 1

And Knowing is half the battle.

G.I. JOE.

Mail that to your congressman.

I can't find it now, but there was another story where they were going to use another metal that was going to come from China that was $11/pound. I made a comment that was nice they were going to replace lead with something that weight and preformed the same as lead from China so China could slip in lead later in the process and we would never notice and still pay $11/pound.

Edited May 29, 2011 by vontar

[Magiccarpetrides]

The Barnes triple shocks are excellent performers, but like Caster I don't see how they could afford to switch to copper as high as it is now.

[Guest JoeNashville]

Oh this is certainly a decision made by idiots.

Thanks.

We just need to realize that the 5.56 was never intended or designed to do what they are try to get it to do now. If they are going to keep using the 5.56 they need to go back to the original specs then design a new long range caliber.

Dolomite

Gee, I wonder why my faith in the military and government doesn't seem to improve. :-((

[East_TN_Patriot]

Another decision by a commission... the 5.56 never was an effective round.

Anything less than a .30 cal is no good... they should just stick to the .308...

Really? There are many thousands of dead folks who'd question that assertion.

[tnhawk]

6.8 is good also. Size,Kinetic energy, Weight. Kind of a in between of the 7.62 and 5.56. I agree about the 5.56. It's kind of like a video game where people get shot several times before going down. With 6.8 or 7.62, they're down.

I'd prefer 7.62, the 6.8 would be a good choice as well. Those making the decision for the military, will likely have never fired a rifle in their lives.

[Guest clownsdd]

If they put the bullets in a body, ya don't have to worry about the environment:)

[Guest 556or762]

If they put the bullets in a body, ya don't have to worry about the environment:)

Here, Here, all you have to do is leave the bullet inside the victim and the lead poisoning issue is a good thing, I mean come on has there ever been a dead guy sue for lead poisoning?

[Dolomite_supafly]

It is only when you ingest lead that it becomes a problem. I have lead in my body that has been there for at least 20 years and probably closer to 25. Never had an issue.

Dolomite

[chemprof]

Dolomite,

I just want to say I really enjoy reading all your posts. Your are a very informed shooter and I can tell you have the experience to back up what you say. You may not claim to be an expert, but you are as close to one as I have ever seen. Thanks!

I was just thinking the same thing! Dolomite--you should be hired immediately by these manufacts! "Head Ballistics Engineer" sound good?

[Guest 556or762]

It is only when you ingest lead that it becomes a problem. I have lead in my body that has been there for at least 20 years and probably closer to 25. Never had an issue.

Dolomite

I think its probably because of the supafly part of that handle I mean superman can handle lead why cant supafly, I have a couple of scars from bullet fragments that are a little over a year old that have never completely healed up they are still more of a reddish color guess the haji that loaded that mag just got done squatting and didnt wash up, that or all the depleted uranium and dust had something to do with it! hmm.

[Guest mosinon]

It is only when you ingest lead that it becomes a problem. I have lead in my body that has been there for at least 20 years and probably closer to 25. Never had an issue.

Dolomite

As far as I know you need to worry about lead oxide not a lead slug in ya.

[Guest bkelm18]

It is only when you ingest lead that it becomes a problem. I have lead in my body that has been there for at least 20 years and probably closer to 25. Never had an issue.

Dolomite

Inhalation can also cause exposure, and very rarely skin absorption.