The Thompson Submachine Gun have been imagined by John T. Thompson during World War I. It main purpose was to clear quickly a trench with a automatic small arms chambered in .45 ACP, the same ammunition as the Colt M1911, but the Thompson have been finalized in 192. Meanwhile, it major contract source dried up with the armistice of 1918, it was sell to civilian law enforcement agencies in respectable quantities. This gun have numerous nickname : "Tommy Gun", "Annihilator", "Chicago Piano", "Chicago Style", "Trench Broom", "Trench Sweeper", "The Chopper", and simply "The Thompson".
The M1928 Thompson was feed box mag and the famous drum mag (Chargeur Camembert in french), and M1 Thompson was feed by box mag only. It was widely use during the Prohibition era, and World Ward II by allied troops.
At the end of War, the thompson was grudually replaced by the M3 Grease gun, less expensive, and much easier to produce than the Thompson.