The M1911 is a .45 ACP caliber pistol originally made by Colt, and is now the most copied pistol design in the world. It was designed in the early 1900s by John Browning and was used in battle by many soldiers in World War I, World War II, The Korean War, and in the Vietnam War. It is semi-automatic and can fire a bullet each time the trigger is pulled. Military versions of the gun can hold seven or eight rounds inside its magazine and one more in the chamber. M1911 style guns are still made today and are for sale.