The Auto-Ordnance Thompson 1927A1 is a semi-automatic rifle chambered in 45 ACP that comes standard with a 20-round stick magazine but it can accept stick or drum magazines of much higher capacities. Including the compensator available barrel lengths are 16.5 and 18 and they are accompanied by either walnut or black synthetic stocks fore grips and pistol grips. The Thompson 1927A1 includes a blade front sight and an adjustable rear sight. A sling mount rounds out the Thompson 1927A1s features. Details Action Semi Auto - Caliber .45 ACP - Capacity 20 plus 1 - Finish Black - StockGrip Fixed Walnut - Sights BladeAdjustable - Barrel Length 16.5 - Overall Length 41 - Weight 13 lb - All the classic details of the time honored original are reproduced in todays semi-auto Thompson. The frame and receiver are machined from solid steel or aluminum. The wood is genuine American walnut. This .45 caliber carbine features a 16 12 finned barrel compensator and is available with a blued steel receiver or a lighter weight aluminum receiver. This configuration is our most popular model.