What is 25 ACP? The 25 Automatic Colt Pistol, or 25 ACP, is one of John Browning‘s lesser known creations. It is a 25 caliber centerfire pistol cartridge that usually shoots projectiles between 30 and 50 grains in weight. The 25 ACP was designed back in 1905 for Fabrique Nationale’s Pocket Pistol. The little pistol […]