Army begins shipping improved 5.56mm cartridge


found on the web … -cartridge

PICATINNY ARSENAL, N.J. (June 23, 2010) – The Army announced today it has begun shipping its new 5.56mm cartridge, the M855A1 Enhanced Performance Round, to support warfighters in Afghanistan.

The new M855A1 round is sometimes referred to as “green ammo.”

The new round replaces the current M855 5.56mm cartridge that has been used by U.S. troops since the early 1980s.

The M855A1 resulted in a number of significant enhancements not found in the current round, officials said. They explained these include improved hard-target capability, more dependable, consistent performance at all distances, improved accuracy, reduced muzzle flash and a higher velocity.

During testing, the M855A1 performed better than current 7.62mm ball ammunition against certain types of targets, blurring the performance differences that previously separated the two rounds.

The projectile incorporates these improvements without adding weight or requiring additional training.

According to Lt. Col. Jeffrey K. Woods, the program’s product manager, the projectile is “the best general purpose 5.56mm round ever produced.”

Woods said its fielding represents the most significant advancement in general purpose small caliber ammunition in decades.

The Enhanced Performance Round contains an environmentally-friendly projectile that eliminates up to 2,000 tons of lead from the manufacturing process each year in direct support of Army commitment to environmental stewardship.

Woods said the effort is a clear example of how “greening” a previously hazardous material can also provide extremely beneficial performance improvements.

Picatinny Arsenal’s Project Manager for Maneuver Ammunition Systems manages the M855A1 program.

Project Manager Chris Grassano called the fielding "the culmination of an Army enterprise effort by a number of organizations, particularly the Army Research Laboratory, Armament Research Development and Engineering Center, Program Executive Office for Ammunition and the Joint Munitions Command.

“The Army utilized advanced science, modeling and analysis to produce the best 5.56mm round possible for the warfighter,” he said.

The M855A1 is tailored for use in the M-4 weapon system but also improves the performance of the M-16 and M-249 families of weapons.

A true general-purpose round, the M855A1 exceeds the performance of the current M855 against the many different types of targets likely to be encountered in combat.

Prior to initial production, the EPR underwent vigorous testing. Official qualification of the round consisted of a series of side-by-side tests with the current M855.

Overall, the Army fired more than 1 million rounds to ensure the new cartridge met or exceeded all expectations. The M855A1 is without question the most thoroughly tested small caliber round ever fielded, Woods said.

The Army has recently completed the Limited Rate Initial Production phase for the M855A1 and is beginning the follow-on full rate production phase where plans are to procure more than 200 millions rounds over the next 12-15 months.

The M855A1 Enhanced Performance Round is the first environmentally-friendly bullet resulting from a larger “greening” effort across the Army’s Small Caliber Ammunition programs. Other greening efforts include 5.56mm tracer, 7.62mm ball and green primers.

Soldiers in Afghanistan will begin using the new, improved round this summer.

thanks to Rob de Heer



Interesting design.


Great info Gyro! I hope our Troops get that new round ASAP!

Will that round ever be available to civilians down the road?



This is an interesting development in the ammunition world that we addicts live in! :-)

I’m wondering, are the steel cores hardened or just mild steel?

  1. I do not think ATFE would allow this round to be sold commercially, as they have already made the M995 5.56x45mm verboten. Nor do I think ATK would attempt to market it commercially even without any fedLE restrictions.

  2. The info I’ve seen on the M855A1 shows a large number of false starts and revamps due to projectile issues. Problems with accuracy, high temps, etc. have resulted in several delays.

  3. The M855A1 looks to have some advantages, at least in intent (optimized for M4-length weapons, etc.). If you want to see some actual performance-based developments (ie, WHO CARES ABOUT THIS ‘GREEN’ JUNK), look at the Navy’s Mk318 Mod 0 and related pills. Actual commercial bullet technologies applied to a .mil item.

There’s a cross-section pic of the M855A1 pill I’ll attempt to post…wish me luck! Didn’t work. Dangit. The core is much larger/longer than the penetrator in the M855, and actually resembles (to me) an unsleeved .50BMG salvo payload in cross-section.


Hardened steel - as with the core tip in the M855, but exposed instead of contained within the jacket. Both might be described as semi-armour-piercing (SAP), but armour penetration of the A1 is improved.


I’m not sure - it is in principle the same kind of SAP design as the M855, rather than the full-AP type like the M995.

Yep, as discussed here in another thread.

That would be useful - does it show the current copper plug rather than the earlier bismuth one?


Thanks for the reply Tony. I’ve also spotted a pic of an M855A1 with a copper colored protruding tip:


I presume this tip is also made of steel but is treated against corrosion?

And a ballistic question: in what way has this bullet an improved capability to defeat soft targets like humans? I see a hard steel and a hard copper core, packed in a hard jacket so deformation or shattering in fragments don’t seem to be an issue. Does this bullet have better tumbling capabilities compared to the regular M855 or so or is it likely to break up in two pars upon impact on tissue? Both improved penetration on hard targets and improved capability to defeat soft targets seems quite contradictory…


And here’s a .mil presentation photo of the Mk318 Mod0 5.56x45mm (SOST).

Basically it’s Federals’ Trophy Bonded Bear Claw tech applied to a JHP bullet (TBBC bullets in commercial and LE products are JSP). The TBBC pill is a game changer for 5.56x45mm performance, at least in the barrier tests I’ve been present for. The solid copper Barnes bullets are also a huge step forward.

Tony, my sourness towards the .gov allowance of the M855A1 is based on the ATFE’s past silliness with regards to ammunition and my personal experiences with the issue…I hope your optimism translates to commercial release since the M855A1 bullet looks promising.

I’ve heard that the 5.56 SOST procurement is the reason that ATK discontinued it’s commercial .223 TBBC offering a while back…maybe just for production/resource allocation? Either way it means a net loss for the commercial .223 end-user.

I’m going to try to get some samples or product swag from my ATK rep; if anything cool comes in I’ll post it ASAP.


I expect so - they would have to apply some kind of anti-rust coating or treatment, but I don’t know what they’re using.

The main problem with the M855 is that it suffers from erratic yaw performance on impact: sometimes the bullet upsets rapidly and creates a large wound channel, at other times it just punches a small hole right through. The M855A1 is supposed to show a much more reliable yaw performance (as does the MK318 Mod 0 SOST).


[quote=“Mwinter”]And here’s a .mil presentation photo of the Mk318 Mod0 5.56x45mm (SOST).

Basically it’s Federals’ Trophy Bonded Bear Claw tech applied to a JHP bullet (TBBC bullets in commercial and LE products are JSP). The TBBC pill is a game changer for 5.56x45mm performance, at least in the barrier tests I’ve been present for. The solid copper Barnes bullets are also a huge step forward.[/quote]
I think it should be pointed out that, unlike a hunting bullet, the MK318 is not designed to expand on impact - that would cause legal problems.

I wouldn’t say I’m optimistic - I was just being logical. But I’m aware that logic doesn’t necessarily have much to do with such decisions.


[quote=“Mwinter”]There’s a cross-section pic of the M855A1 pill.
The core is much larger/longer than the penetrator in the M855, and actually resembles (to me) an unsleeved .50BMG salvo payload in cross-section.

This shows the rejected version with the bismuth alloy plug, which showed erratic accuracy as the alloy softened in hot weather. The production version has a copper plug.


I think I remember seeing some of the bismuth core/tip version projectiles at Pepper’s table at SLICS, and the ones I saw were the copper colored or brownish type. I thought that was the color for the bismuth ones, and that the current production steel ones were gray like above? Or were there 2 tip colors for the bismuth version?

Legally, until the BATFE updates their list of federally recognized “armor piercing cartridges” I don’t think the M995, M993, or this new M855A1 cartridge would be restricted per-se, although it’s moot since nobody should technically be able to possess these for resale in the first place since they are only issued to the military (and a few lucky collectors through odd channels). All of these newer AP / semi-AP cartridges are supposed to be property of the U.S. government, but I have seen belts of M995 from a SAW for sale before (legal?? nobody seemed to notice or challenge the sale on Gunbroker). The last revision of the armor piercing list that I was aware of in the “Federal Firearms Regulation Reference Guide” was from the 2005 version, and I think that version just had a slight grammatical change from a list that had not changed since 1996 at least…?? If all the troops are issued this ammo though, we will see plenty of it from quasi-legal bring-back stuff; though I know they’re not supposed to hang onto ammo.


One other thing I was wondering about the M855A1 is how does it perform in the shorter barrels? I’m assuming that it is tailored to the barrels of the M4 carbine which is obviously shorter than the typical M16, but I wonder how they will do in a shorter commando carbine with an 8" to 12" barrel? Or in a commercial gun like Kel Tec’s PLR-16? (I know it’s a silly gun). Anybody know how fast the powder in the ammo is?


When did the M-855 get a hardened core? All the ones I have sectioned or examined were not hardened…

M-995 for sale on gunbroker…highly unlikely to be the real thing.



Terminal effects of M855A1 are reportedly more consistent than M855, but wounding is no more severe.


I think that’s nonsense. The Mk318 is an evolution of the TBBC hunting bullet (which was designed to expand), and I’d bet money that Mk318 expands in soft tissue at least as well as the TBBC.

The PR spin given to legally justify combat use is that Mk318 was “designed for barrier blind performance,” not expansion; that it expands in people is just a “convenient” coincidence.


I think the correct term for what happens to the tip on the mk318 that the military is using is “deformation”, which aids in post-impact yawing. It may or may not expand, but it deforms, with the same idea in mind as the 5.45 and 7.62 Russian cartridges that have an air pocket in the tip. I wonder if the hardness or thickness in the mk318 is much different than the usual ratios of the Trophy bonded bear claw bullet so as to avoid typical expansion in the hollow-point sense? Or the fact that the military caliber being .22 as opposed to the typically larger hunting caliber bullets of the TBBC which were heavier may cause difference in tip behavior or frequency of actual point expansion as far as the Geneva convention is concerned?


That’s what I have always thought, but I have the term “M995” saved as a few variations as one of my saved-searches on GB, and one day several months ago, there it was. The listing was up for maybe 2 days and then the seller took it down. I think the fact that he actually explained that the belt came from an M249 SAW in Iraq, and that there were many questions from bidders about this caused him to change his mind. But I had emails back & forth with him after the fact and he said he just had an in-store offer and sold it, not legal issues… who knows… I stopped being surprised with what appears on Gunbroker and Ebay over a year ago after finding mind-numbing items for low prices. I found a table-top display from Aerojet that was a 2" thick block of 8" x 4" steel armor, with a still radioactive hole drilled through it from a 30mm PGU-14/B DU rd - on Ebay of all places…


“Designed” is a loaded term in the ammo world…Sierra Matchking bullets, as used in US .mil ammo and variously approved by JAG and other oversights, are sometimes described as having the hollow tip as an accuracy-enhancing feature. Also, the method of manufacture (solid base, hollow tip, rather than traditional exposed-lead-base FMJs) allows for a more consistent boattail–again an ‘accuracy’ advantage.

Most people know that hollow points can contribute to expansion/deformation/wounding, and the presence of the boattail is listed in SOST presentations as having a desirable effect (ie less resistance to/enhancing) tumbling in soft targets. This can be construed as a measure to prevent soft-target overpenetration in MOUT, etc., rather than to enhance wounding capability.

‘Designed’ is also used in the Texas Penal Code in reference to AP…“designed to penetrate metal or body armor”. Most modern police JHPs are designed to pass the FBI protocols, one of which is penetrating sheet metal. Never mind whether or not the pills actually defeat said barrier, but oh dear the horror that they are designed to do these things–haha. And no decision has been made as whether or not the law is referring to the penetration of “metal-- AND body armor”…or “metal [armor] or body armor”.

The M855A1 and SOST are demonstrably ‘designed’ to have an enhanced terminal effect, and this is born out in the few tests/simulations I’ve seen. Whether or not this rubs Hague or other legalities the wrong way is subject to interpretation.

DK, the SOST/TBBC pills are being made in 5.56x45, 7.62x51
and .300WM. The cross sections of each appear in that same presentation. The 62gr .223 TBBC LE JSP round from Federal does indeed expand/deform very consistently with high weight retention in actual shootings and tests, and has been issued by my agency, the DEA and a large neighboring agency. I’m glad to see this application getting to military end-users who need it, regardless of how folks have to ‘spin’ it past outdated and impractical protocols.