Rimmed version of .45 ACP designed for use in revolvers without moon clips. Identical to .45 ACP except for the thick rimmed head that allows the cartridge to headspace in a revolver cylinder without a moon clip.
Type: Revolver
Introduced: 1920, United States
Parent case: .45 ACP
Standardization: SAAMI
Bullet diameter: 0.452" (11.48 mm)
Case length: 0.898" (22.81 mm)
Overall length: 1.275" (32.39 mm)
Max pressure: 23,000 PSI
Rim type: Rimmed
Primer: Large Pistol
Typical twist rate: 1:16
Muzzle velocity: 810–1000 fps
Muzzle energy: 265–511 ft-lbs
Effective range: 50 yd
Common bullet weights: 185, 200, 230 gr
Primary use: Self Defense, Target
Production status: Active
Also known as: .45 AR · .45 Automatic Rimmed
History: Developed in 1920 by Peters Cartridge Company for the S&W M1917 and Colt M1917 revolvers — WWII-era service revolvers that had been chambered in .45 ACP using half-moon clips during WWI. The .45 Auto Rim allowed the M1917 revolvers to function as standard revolvers without requiring clips. Still produced today for shooters who prefer to load .45-caliber revolvers individually rather than using…
Notable firearms: S&W M1917, Colt M1917, Any .45 ACP revolver
Similar cartridges: .45 ACP, .45 Colt