The 300 Ruger Compact Magnum, often known as the 300 RCM, is a rimless, short-length rifle cartridge designed to closely resemble the performance of the classic 300 Winchester Magnum cartridge, but chambered in a short-action rifle. Hornady and Sturm Ruger collaborated to produce the rifle cartridge for hunting medium-to-large North American game, which was introduced commercially in 2008 and chambered in a variety of Ruger rifles.
It employs a rimless design case based on the powerful 375 Ruger cartridge, which has the same base and rim diameter of 532 in (13.5 mm) as belted magnum cases based on the 300 H&H Magnum and.375 H&H Magnum. Given cases of identical length, this design allows the 300 Ruger Compact Magnum cartridge to have a larger case capacity than a belted magnum case. The case length was lowered to 2.10 in (53 mm), which is close to the 308 Winchester case since Ruger wanted the cartridge to be chambered in short length bolt-action rifles.
Hornady produces high-performance ammunition for the 300 Ruger Compact Magnum cartridge. The Hornady Superformance Ammunition travels at 3,040 ft/s (930 m/s) with a Hornady 180 gr (12 g) Interbond or SST bullet and 3,310 ft/s (1,010 m/s) with the 150 gr (9.7 g) SST bullet. The higher case capacity and "short fat" cartridge efficiency of the 300 Ruger Compact Magnum result in gains in the neighborhood of 150 fps above the H&H cartridge, and it performs similarly to the 300 Winchester Magnum or 300 WSM.
