US Army's XM1158 Advanced Armor Piercing Round Set to Replace M80A1 EPR

Matthew Moss
by Matthew Moss
XM1158 7.62-mm Cartridge (US Army)

The US Army is moving to supplement and superseded the M993 Armour Piercing round and M80A1 Enhanced Performance Round, introduced back in 2016, with the new 7.62x51mm XM1158 Advanced Armor Piercing Round. In October 2019, the Army authorised the urgent materiel release of the XM1158 round to accelerate its fielding. The Army is planning on a full materiel release for the round in FY 2020.

The XM1158 round was rumoured to have been the partner ammunition to the US Army’s ill-fated Interim Combat Service Rifle (ICSR). The 2019 Annual Report from the Director, Operational Test and Evaluation (DOT&E) confirms that the “XM1158 utilizes a core and penetrator encapsulated in a reverse-drawn copper jacket.”

According to the FY 2019 annual report from the Office of the Director, Operational Test and Evaluation, the “DOT&E will report on XM1158 performance in a classified lethality report upon live fire test completion to support full materiel release in FY20.” So it will likely be a while before we know the round’s true capabilities.

The M240 is one of the Army’s weapon systems which will be using the new XM1158 round (U.S. Army photo by Sgt. Leron G. Richards)

XM1158 was approved for development in 2015 and the Army completed initial live fire testing of the XM1158 in March 2019 to support urgent materiel release. The testing was “conducted in accordance with the DOT&E-approved live fire strategy.” According to the DOT&E’s December 2019 report:

The Army used barrier-protected gelatin targets to enable credible computer modeling of XM1158 performance with the Operational Requirements-based Casualty assessment/Static Dynamic Framework model (ORCA/SDF). To support full materiel release, the Army plans additional testing against other light material barriers and targets to determine the projectile’s ability to perforate operationally relevant targets. The Army will accredit ORCA/SDF to support full materiel release.

The new 7.62x51mm Advanced Armor Piercing Round will replace the current M993 AP round in the M993-linked configuration to provide improve lethality compared to the current M80A1 and M993 cartridges. The round can be used in the Army’s M240 series of machine guns; the Mk 48 machine gun; and the M110 series, Mk 17, Mk 14, and M14 series rifles.


Matthew Moss
Matthew Moss

Managing Editor: & Overt Matt is a British historian specialising in small arms development and military history. He has written several books and for a variety of publications in both the US and UK. Matt is also runs The Armourer's Bench, a video series on historically significant small arms. Here on TFB he covers product and current military small arms news. Reach Matt at:

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  • No one No one on Mar 20, 2020

    Neat, now do the same with M855A1 with it's original powder charge and higher PSI.

    Or hell, maybe just use use an M855A1 projectile with a tungsten core in an LSAT style "casing" for whatever rifle/SAW changes we make.

  • Secundius Secundius on Mar 25, 2020

    @ Vitor Roma.

    Stiletto Systems and BAE share the same production facility located on Radway Green. Also Stiletto Systems is a Ukrainian-owned company. And quit try to block yourself...