6.8x51mm Common Cartridge

The 6.8x51mm Common Cartridge is the round developed for the US Army's Next Generation Squad Weapon (NGSW) program, which replaces 5.56mm-chambered M4A1 carbines and M249 light machine guns and 7.62mm M240 machine guns in close-combat units with a common 6.8mm cartridge and integrated fire-control optic. The cartridge's hybrid-case design (a steel head bonded to a brass body) and its roughly 80,000 psi chamber pressure, both engineered by SIG Sauer as part of its winning NGSW rifle and automatic-rifle submission, push significantly more velocity and energy from the shorter barrels of the XM7 rifle and XM250 automatic rifle than 5.56mm or 7.62mm ammunition, intended to improve range and body-armor penetration. The general-purpose loading carries the military designation XM1186 as part of a wider Common Cartridge family that also includes reduced-range, blank, tracer and force-on-force marking variants. Winchester (operating as Olin Winchester) was awarded the US Army's NGSW ammunition production contract in February 2023 after an earlier 2022 facility-design award, and manages and operates the government-owned Lake City Army Ammunition Plant in Independence, Missouri, where a new roughly 450,000-square-foot dedicated 6.8mm production facility topped out in January 2026 to scale output of the cartridge alongside legacy 5.56mm and 7.62mm lines. Detailed ballistic figures (bullet weight, muzzle velocity) are inconsistently reported across open sources and are not recorded here as data; publicly cited figures place the projectile in the 113 to 135-grain class.