All the classic details of the time honored original are reproduced in today's 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 1/2" finned barrel, compensator and is available with a blued steel receiver. T1-C, the semi-auto "Commando", features parkerized metal and all wood stock, rear grip and horizontal forend in a durable black finish.