The .300 Ruger Compact Magnum or .300 RCM is a rimless, short-length rifle cartridge designed for the hunting of Medium-to-Large-sized North American game. It is designed to closely duplicate the performance of the historic .300 Winchester Magnum cartridge, yet to be chambered in a short length action rifle. The cartridge was designed by Hornady and Ruger in partnership and released commercially in 2008 and chambered in various Ruger rifles.