The .300 RUM features a rebated rim much like the .300 Canadian Magnum so as to allow the cartridge to function in the Remington M700 action without having to increase the bolt and bolt face diameter of the action. Unlike the belted Magnum cases based on the .375 H&H Magnum cartridge, the .300 RUM does not have a belt. All things being equal, a beltless cartridge would feed more reliably and more smoothly than a belted cartridge. Furthermore, as this is a beltless cartridge headspacing is designed to take place on the shoulder, which is considered beneficial by some as it is thought to promote accuracy and prolong case life of the cartridge. As modern belted magnums such as 7mm Remington Magnum and .300 Winchester Magnum actually headspace on the shoulder despite retaining the belt found on their parent cartridge, belted or unbelted is basically irrelevant in discussions of modern cartridges, and particularly so in discussions of unbelted cartridges.