A 5.56x45mm NATO M855A1 cartridge with a 4 gram armor-piercing bullet with a steel penetrator tip over a copper alloy core with a copper semi-jacket in a brass case.
This cartridge was designed to improve the penetration capabilities of the 5.56x45mm NATO M855 cartridge of the United States Army, being able to pierce basic and intermediate body ballistic protections, however, due to its design, it has a high bounce probability on various surfaces.
