The Auto-Ordnance Thompson 1927A-1 in .45 ACP with 16.5-inch barrel is the semi-auto civilian version of the iconic Thompson submachine gun, featuring a 16.5-inch barrel to comply with federal rifle length requirements. It accepts both drum and stick magazines and has the distinctive finned barrel and compensator of the original military Thompson. A significant piece of American firearms history. Type: Semi-Auto Rifle Action: Blowback Caliber: .45 ACP Capacity: 20 Year introduced: 1976, USA Weight: 10.8 oz Overall length: 41" Status: Active Intended use: Collecting, Plinking, Home Defense