MFR#: T1UPC: 602686211000All 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 or a lighter weight aluminum receiver. This configuration is our most popular.