The 300 Ruger Compact Magnum (RCM) was introduced in 2008 as a joint project between Hornady and Ruger. It is based on the 375 Ruger case necked down and shortened to 2.0X-inches, enabling it to be housed in short (308 Winchester-length) bolt-actions. The unbelted case has a rim and base diameter of .532-inch, the same as standard belted magnums. This gives it a fatter case, allowing more powder capacity, but the same bolt face diameter, allowing simpler manufacturing and generally reduced feeding issues. Hornady remains the primary source of ammunition and Ruger the primary source in rifles. Although it has not become extremely popular the 300 RCM is a sound design and effective "fast 30-caliber" cartridge, with 150-grain bullets at 3170 feet per second and 180-grain bullets at 2900.
