.45 Auto Rim Load Data & Reloading Guide

The .45 Auto Rim, developed in 1920 by the Peters Cartridge Company, was specifically designed for use in revolvers chambered for the .45 ACP cartridge. Its introduction addressed the need for a rimmed cartridge to be reliably used in revolvers originally designed to shoot the rimless .45 ACP with moon clips. The .45 Auto Rim features a thick rim that compensates for the space typically occupied by moon clips, allowing for smooth extraction in revolver cylinders.

Key technical characteristics include a bullet diameter of .452 inches and a case length of 0.898 inches. Its rimmed design and robust construction ensure reliable ignition and extraction, especially in vintage or service revolvers. Ballistically, the .45 Auto Rim parallels the performance of the .45 ACP, generally producing muzzle velocities around 850 feet per second with a 230-grain bullet, providing sufficient energy for various uses while maintaining manageable recoil.

Typical bullet weights for this caliber include 185 to 255 grains, with 230 grains being the most common in factory loads. It is primarily used for target shooting, personal defense, and, to a lesser extent, small game hunting due to its adequate stopping power and controllable nature. Its popularity endures among shooting enthusiasts who enjoy using historical firearms with traditional loads while maintaining accurate performance.

For reloaders, the .45 Auto Rim presents several advantages. Its thicker rim simplifies the process by eliminating the need for moon clips, ensuring easier handling and enhanced convenience in revolver loading and unloading. The cartridge's straightforward design and availability of reloading components offer versatility in tailoring loads for specific applications, whether one desires reduced-recoil target rounds or higher-pressure defense loads. Reloaders can also experiment with a variety of bullet shapes and compositions, adding to the cartridge's allure for those interested in precision shooting and historical firearms collection.