The Colt Commander is a single-action, semi-automatic, magazine-fed, and recoil-operated handgun based on the John M. Browning designed M1911. It was the first mass-produced pistol with an aluminium alloy frame and the first Colt pistol to be chambered in 9mm Parabellum. Colt made several variations of the Commander and offered it in .45 ACP and .38 Super chamberings. Other variants followed with different degrees of factory accurizing and materials.