A type of short range machine gun that is carried as a personal weapon and uses pistol ammunition.
Bare-chested children and their parents gathered in doorways, on roofs and in windows as he passed, watched warily by Brazilian troops carrying submachine guns. - New York Times, 09/03/2007 http//www.nytimes.com/2007/03/09/world/americas/09cnd-prexy.html?ref=world