The Colt 1911 is the standard sidearm used by the U.S. during WWII. It was also given in large numbers to other countries such as Britain under the Lend-Lease policy. It is a semi-automatic handgun that is chambered for the .45 ACP cartridge. It's capacity is 7 rounds. Compared to other semi-auto pistols, it has the most damage but highest recoil.
The damage advantage is only really noticed in Arcade Mode.