Original commercial Thompson submachine gun with the Blish lock (later found unnecessary). Available with 20/30-round box or 50/100-round drum. Used by Prohibition-era gangsters and law enforcement before military adoption. Type: Submachine Gun Action: Blowback Caliber: .45 ACP Capacity: 50 Year introduced: 1921, USA Weight: 128 oz Overall length: 33.7" Status: Discontinued Military use: Yes Intended use: military