The Thompson is a .45 caliber American submachine gun, invented by John Talifero Thompson in 1919.
It was initially marketed to the law enforcement officers as "Thompson's anti-bandit gun", but eventually became widely associated with the mafia and gangsters. The weapon earned various nicknames such as the "Tommy Gun," the "Trench Broom," the "Trench Sweeper," the "Chicago Piano," the "Chicago Typewriter," and the "Chopper." The gun was adopted by the United States army during World War II, and remained in service until the Vietnam War.
This tag applies to all Thompson variants. The M1921 and M1928 feature a finned barrel, a charging handle knob, vertical foregrip with finger grooves, adjustable iron sights, and drum magazines. The WWII-era M1/M1A1 simplified the design, with rectangular handguard, lack of muzzle device, charging handle on the right, and only accepting stick magazines.
