The Colt Single Action Army (also known as the SAA, Model P, Peacemaker, M1873, and Colt .45) is a single-action revolver primarily chambered for .45 Colt, and is made by Colt's Manufacturing Company. It was one of the first revolvers designed specifically to use metallic centerfire cartridges, replacing the cap-and-ball revolvers in use during the latter half of the 1800s.