Thompson submachine gun

The Thompson submachine gun (also known as the "Tommy gun", "Chicago typewriter", or "trench broom") is a blowback-operated, selective-fire submachine gun, invented and developed by Brigadier General John T. Thompson, a United States Army officer, in 1918. It was designed to break the stalemate of trench warfare of World War I, although early models did not arrive in time for actual combat. The Thompson saw early use by the United States Marine Corps during the Banana Wars, the United States Postal Inspection Service, the Irish Republican Army, the Republic of China, and the FBI following the Kansas City massacre.

The weapon was also sold to the general public. Because it was so widely used by criminals, the Thompson became notorious during the Prohibition era as the signature weapon of various organized crime syndicates in the United States in the 1920s. It was a common sight in the media at the time, and was used by both law enforcement officers and criminals. The Thompson was widely adopted by the U.S. armed forces during World War II, and was also used extensively by other Allied troops during the war. Its main models were designated as the M1928A1, M1, and M1A1 during this time. More than 1.5 million Thompson submachine guns were produced during World War II.