The M1911 is a single-action, semi-automatic, magazine-fed, recoil-operated pistol chambered for the .45 ACP cartridge. It served as the standard-issue sidearm for the United States Armed Forces from 1911 to 1986. It was first used in later stages of the Philippine–American War, and was widely used in World War I, World War II, the Korean War, and the Vietnam War. Technical Data Weight 2.44 lb (1,105 g) empty, w/magazine Length 8.25 in (210 mm) Barrel length Government model: 5.03 in (127 mm) Commander model: 4.25 in (108 mm) Officer's ACP model: 3.5 in (89 mm) Cartridge .45 ACP Action Short recoil operation Muzzle velocity 825 ft/s (251 m/s) Feed system 7-round standard detachable box magazine