M855A1 EPR Officially Adopted By US Marine Corps

Nathaniel F
by Nathaniel F
The lead-free M855A1 5.56mm cartridge.

The United States Marine Corps has finally officially announced its adoption of the 5.56mm M855A1 EPR round, developed in the late 2000s by the US Army, marking an important step towards ammunition commonality between the two services. Until now, the USMC has officially only used the legacy M855 round, and to a more limited extent the SOCOM-developed Mk. 318 SOST round, refusing to adopt the US Army’s new M855A1. The Marine Corps Times reports that the Corps’ Combat Development Command has begun procuring the round for stockpiles, with its official adoption coming in 2018:

The Marine Corps will begin ­procuring the enhanced round for its combat stockpiles this fiscal year, said ­Woodburn. ­Deployed Marines who are ­issued M855A1 rounds can use them now.

The M855A1 round, which offers greatly enhanced barrier penetration and more consistent lethality than legacy M855 ammunition, generated controversy when early versions caused significant issues in the USMC’s then-new M27 Infantry Automatic Rifles. Specifically, when combined with legacy USGI magazines, the exposed hardened penetrators of the M855A1 round would prematurely erode the M27’s tighter forcing cone. An anonymous source told TFB that the USMC’s adoption of the Magpul PMag, which virtually eliminates the erosion issue, was a major step towards the adoption of the M855A1 itself. Further, for logistical reasons, the source said that the USMC has been quietly using M855A1 in theater for months already, with good success. Lt. Col. (ret.) Chris Woodburn spoke highly of the M855A1’s lethality:

“The M855A1 provides improved performance over the current M855, 5.56mm round in a lead-free form factor, and provides improved steel penetration, hard- and soft-target terminal effects, with more consistent terminal effects than the M855 at ranges out to 600 meters,” Woodburn told Marine Corps Times.

Nathaniel F
Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.

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  • American Patriot American Patriot on Dec 17, 2017

    ...And we need lead-free military ammo why? Because it's more expensive & we know the Govt has an endless supply of money, thanks taxpayers.

  • Fred Weller Fred Weller on Dec 17, 2017

    Yeah. Best performing varmint round yet. Lipstick on a pig. There's a reason why the Marines in Afghanistan had to start carrying M-14s in 7.62. The 5.56 is inadequate. By the time the 5.56 goes uphill a few hundred meters, it has the trajectory of a thrown rock and can't breach cardboard.

    • Mountain Mountain on Dec 22, 2017

      @Fred Weller M855A1 at 1000m pierces kevlar designed to stop 7.62x51 at 1000m.
      The trajectory of 7.62x51 is terrible too, and has a shorter point blank range, but with double the weight (lack of fire superioritiy), triple the recoil, and 10 rounds less per mag, also a heavier rifle and shorter barrel for the same overall lenght. Not that great...