U.S. Army Sub-Machine Gun -- U.S. Army Corporal demonstrates the new American submachine gun, a light but hard-hitting. 45 ***** weapon developed by the Ordnance Department ***** Army Service Forces. The new gun, which ***** only nine pounds and fires 450 rounds a minute, small enough to be carried in a brief case. July 26, 1943. (Photo by U.S. Office of War Information Picture).