.45 Auto Rim In .45 Colt

by
posted on April 25, 2014
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
qanda2015_fs.jpg (2)

Q. Can you safely shoot a .45 Auto Rim cartridge in a revolver chambered for a .45 Colt? A buddy of mine gave me some the cartridges, but I don’t have a gun in .45 Auto Rim. I do have a .45 Colt, though, and it looks like it should work.

A. I would not encourage anyone to attempt to fire a .45 Auto Rim cartridge in a cylinder chambered for .45 Colt. Aside from differences in the dimensions of the cartridge case, the Auto Rim round has a significantly thicker rim, approximately 0.090" versus approximately 0.060". This could certainly cause headspace and functioning problems. If the revolver in question is supplied with a separate cylinder specifically for the Auto Rim cartridge, there should be no problem. A number of firearm manufacturers have over the years offered .45 revolvers with dual cylinders, one for .45 Auto Rim or .45 ACP cartridges and one for .45 Colt.

-Reid Coffield

Originally published September, 2006

Latest

Ithaca Model 66  Super Single Shotgun
Ithaca Model 66  Super Single Shotgun

I Have This Old Gun: Ithaca Model 66 Super Single Shotgun

There was a time when a lever-action, single-shot scattergun was all the rage. Today, it still has some value and practical utility.

Cold-Weather Carry: 5 Great Items for Winter CCW

Don’t let the cold stop you from being prepared should things get hot.

Sighted Fire vs. Point-Shooting

A long-standing argument among handgunners revolves around the concept of sighted fire versus point-shooting. A more productive approach is to understand the problem each is trying to solve.

Derya Expands TM22 Family with Timekeeper & Pump Models

Derya continues the expansion of its rimfire line with two new models for 2026, an update of the original semi-auto TM22 and a new pump-action version.

Gun of the Week: Taurus RPC

The Taurus RPC is a welcome addition to the growing marketplace of PDWs, or personal defense weapons, a concept that pairs pistol-caliber cartridges with larger-format firearms.

The Armed Citizen® Nov. 13, 2026

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

Interests



Get the best of American Rifleman delivered to your inbox.