Thompson submachine gun

The Thompson was a family of American submachine guns that became infamous during the Prohibition era. It was a common sight of the time, being used overwhelmingly by both law enforcement officers and criminals. The Thompson was also known as the "Tommy Gun", "Chopper", "Chicago Typewriter" and "Chicago Piano". The Thompson was favored by soldiers and civilians alike for its compactness, large .45 ACP bullet, and high volume of automatic fire.