The M1911 is a semi-automatic, recoil-operated, single-action handgun. It is fed from a 7-round detachable box magazine. It fires the .45 ACP round. It was invented by John Browning in 1911, hence the name. It was the standard sidearm of the U.S. Military from 1911 to 1985, when it was replaced by the Beretta M9. However, it still in limited service with Marine Force Recon and many law informant units.