The 32 Auto is a centerfire pistol round. .32 Auto or .32 Automatic is also called .32 ACP, where ACP stands for Automatic Colt Pistol. Developed by John Browning, a firearms designer, the .32 Auto is a semi-rimmed, straight-walled cartridge. Other names for the .32 Auto are 7.62x17mmSR and 7.65mm Browning Short.