The .45 Auto Rim

(Left to Right) A .45 Auto Rim with a heavy-cast 255 grain SWC, the .45 Colt with a 260-grain bullet and the .45 ACP with a 230-grain JHP. The .45 AR is easily among the most versatile of all cartridges.

I tend to look forward rather than back. The fundamental premises of youth, however, are hard to shake. I grew up among experienced shooters, hunters and ex-soldiers who had strongly ingrained skepticism concerning the self-loading handgun.

Old black revolver, barrel pointed to the left on a white background
This grand old revolver is an interesting shooter, to say the least.

Any dissent from that dictum was viewed with suspicion. The majority of handguns they used were Smith and Wesson revolvers, with an occasional Colt. A person with little money or who did not understand handguns might own an Iver Johnson or Harrington and Richardson. A few of the more “gunny” types had Lugers or P38s put up somewhere. The incomparable alien appearance of the German guns left me speechless at about 10 or 11 years old.

My grandfather took a good bit of small game with his personal Smith and Wesson .38. I used my other grandfather’s Colt .32 to take small game. My grandparents and father indulged my interests, and I never let them down. I have encountered many interesting handguns; my first big-bore handgun, purchased for less than $100, was a Smith and Wesson Model 1917 revolver.

Black revolver with focus on a nonstandard front sight on a white background
The front sight of this revolver is non-standard, probably a custom addition.

I cannot think of a better choice because not only did I learn marksmanship, handling of a big bore, handloading and hunting, I also learned how to research historical facts. The old gun gave only fair-to-middling accuracy with cast bullets, which is true of most 1917s, yet it served well.


I will tell this thrice-told tale briefly. Before the United States entered World War I, Britain was hard-pressed for handguns and purchased scores of Colt and Smith and Wesson revolvers in .455 Webley, which proved useful in trench warfare.

When America entered the war, we had perhaps 30,000 1911 handguns. We needed to arm every soldier for what was shaping up as a pistol war. Colt simply could not fill the need, and neither could Remington UMC or other contractors. Smith and Wesson chambered the revolvers ordered for the .45 ACP cartridge. Since the .45 automatic cartridge does not have a cartridge-case rim, the rounds simply fell into the cylinder. After early testing, a properly chambering cylinder design was implemented, although the ejector star would not eject a rimless cartridge.

So Smith & Wesson developed the half-moon clip, which held three cartridges. Those clips neatly solved the problem of using a self-loader’s cartridge in the revolver by providing head space. Smith and Wesson delivered the cartridges loaded in the half-moon clips (all to avoid having two handgun calibers in the supply chain).

Black revolver, barrel pointed to the right, on a white background
This revolver is smooth, and while not as accurate as modern Smith and Wesson revolvers, it is accurate enough for most uses.

The result was the fastest revolver to load and unload ever made in America; simply snap the clips in place. With a conventional revolver, the barrel must be pointed upward to quickly unload the cylinder. Not so with the 1917. Simply hit the ejector rod, and the half-moon clips and cartridges are ejected—a neat trick.

Many years later, the manufacturer developed full-moon clips holding six rounds. Currently available from Wilson Combat, these full-moon clips give shooters every advantage and a five-pack is only $4.95 at (Note: Pricing is subject to change without notice at any time).

The original 1917 revolver, and more modern Smith and Wesson 625, are interesting revolvers. So is the Colt 1917 (Colt and Smith and Wesson revolvers were named 1917). The modern Taurus Tracker is a light, K-frame revolver chambered for many interesting cartridges, including the .45 ACP.

Silver Smith and Wesson 1917 in man's hand, barrel pointed to the right
The Smith and Wesson 1917 is surprisingly lively in the hand. This one has been hard chrome-plated.

The Taurus Tracker is a five-shooter that takes five-shot, full-moon clips. Those so loaded are the fastest to load and unload of any revolver. However, there is another option.

(Left to Right) The thin case rim of the .45 Colt, the heavy case rim of the .45 Auto Rim and the automatic pistol design of the .45 ACP.
(Left to Right) The thin case rim of the .45 Colt, the heavy case rim of the .45 Auto Rim and the automatic pistol design of the .45 ACP.

The .45 Auto Rim

After World War I, the U.S. military declared the 1917 revolvers as surplus. They were inexpensive and readily available. Cops, outdoorsmen and anyone who wanted a high-quality, big-bore revolver latched onto them. They were available for a much lower price than the .44 Special or the .38-44 Outdoorsman.

Man holding a Barnes X bullet
A handload using the Barnes X bullet improved the lethality of the .45 Auto Rim.

However, many shooters did not like using the moon clips. Great for combat, they were an aggravation for day-to-day use. So Remington introduced the .45 Auto Rim cartridge, which is simply a .45 ACP with a revolver-like rim. The cartridge head spaces properly and is ejected by the ejector star. Moon clips cannot be used with the .45 AR cartridge. That gives you the advantage of using the moon-clipped revolver for personal defense or competition and the .45 Auto Rim for hunting or target practice.

With the introduction of the .45 AR, handloaders got busy. The 230-grain lead bullet in the original loading is loaded to .45 ACP velocity, about 830 fps. Handloaders realized that, with the case capacity and strong head of the .45 AR, things could be improved considerably. It is not difficult to jolt a 255-grain SWC to 900 fps. A 225-grain Flat Point may be sent to 1,000 fps. Take care in using those handloads because the condition of original handguns varies considerably, yet each is within the realm of .45 AR performance.

(Left to Right) A .45 Auto Rim with a heavy-cast 255 grain SWC, the .45 Colt with a 260-grain bullet and the .45 ACP with a 230-grain JHP.
(Left to Right) A .45 Auto Rim with a heavy-cast 255 grain SWC, the .45 Colt with a 260-grain bullet and the .45 ACP with a 230-grain JHP. The .45 AR is easily among the most versatile of all cartridges.

Today, Buffalo Bore offers good-quality outdoor loads that perform well in a good, tight 1917 revolver. Cor®Bon offers .45 AR defense loads using the DPX bullet. There is no reason not to be well armed with the 1917 revolver or one of the later Smith and Wesson M25 revolvers.

If you choose the Taurus Tracker, you must stick with moon clips because the .45 AR does not chamber and allow the cylinder to close. That is OK, although you must always use the Tracker with the five-shot moon clips or you have to pick out the spent cases one at time.

Whatever the attributes of the .45 ACP—a clean powder burn, accuracy, economy with handloads—the 1917 revolvers in .45 ACP have those attributes in spades. With careful handloads in the .45 Auto Rim cartridge case, you may approach, to an extent, the performance of most factory .45 Colt loads—all of that in a quality, double-action revolver.

If you own one of the modern 625 revolvers, you are in an even better position. The .45 Auto Rim is a great old cartridge that is a joy to use and fire.

Side Notes

The Cor®Bon 160-Grain DPX .45 AR load is similar to the .45 ACP 160-grain Cor®Bon loading for use in compact self-loaders. The .45 AR load is rated at 1050 fps from the factory. In my personal SW 1917 revolver, the load averaged 1111 fps. That is greater than the factory claim, which seems SOP for Cor®Bon.

The load is accurate enough for personal defense. All factory loads, in this revolver, break about 4 inches at 25 yards. At 7 yards, they cut one ragged hole, more than enough for personal defense. Only by using a heavy, long-nose-cast semi-wadcutter is accuracy improved.

The Cor®Bon load strikes to the point of aim at personal-defense range, while bullets of 230 grains strike considerably high. All in all, it is a great loading and good personal defense option from a maker that delivers custom-grade quality.


About the Author:

Bob Campbell

Bob Campbell’s primary qualification is a lifelong love of firearms, writing, and scholarship. He holds a degree in Criminal Justice but is an autodidact in matters important to his readers. Campbell considers unarmed skills the first line of defense and the handgun the last resort. (He gets it honest- his uncle Jerry Campbell is in the Boxer’s Hall of Fame.)

Campbell has authored well over 6,000 articles columns and reviews and fourteen books for major publishers including Gun Digest, Skyhorse and Paladin Press. Campbell served as a peace officer and security professional and has made hundreds of arrests and been injured on the job more than once.

He has written curriculum on the university level, served as a lead missionary, and is desperately in love with Joyce. He is training his grandchildren not to be snowflakes. At an age when many are thinking of retirement, Bob is working a 60-hour week and awaits being taken up in a whirlwind many years in the future.

Published in
Black Belt Magazine
Combat Handguns
Rifle Magazine
Gun Digest
Gun World
Tactical World
SWAT Magazine
American Gunsmith
Gun Tests Magazine
Women and Guns
The Journal Voice of American Law Enforcement
Police Magazine
Law Enforcement Technology
The Firearms Instructor
Tactical World
Concealed Carry Magazine
Concealed Carry Handguns

Books published

Holsters for Combat and Concealed Carry
The 1911 Automatic Pistol
The Handgun in Personal Defense
The Illustrated Guide to Handgun Skills
The Hunter and the Hunted
The Gun Digest Book of Personal Defense
The Gun Digest Book of the 1911
The Gun Digest Book of the 1911 second edition
Dealing with the Great Ammunition Shortage
Commando Gunsmithing
The Ultimate Book of Gunfighting
Preppers Guide to Rifles
Preppers Guide to Shotguns
The Accurate Handgun
The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (2)

  1. Auto Rim cases are hard to find? and expensive. I have about 50 of them with a dubious firing history. I have a S&W Mod. 1955 Target in .45 acp that I picket up @ a Big 5 store that someone dropped on floor. Had slight scuff on cylinder. Picked it up new then ’30 yrs. ago for a song and a dance. The mark is less than the in and out of the holster over the years. Navy and Army pilots in WW 2 would shorten the barrel to 3″ with a Hacksaw to be less gainley in tight spaces. I have made shotsheel loads for it using cut down .30-06 or .308 rifle brass cut to chamber length less 10% for streatch. Use 7.5 shot and WW shotshell powder. Cut off the pedals of .410 shot wads to use as seperator between powder and shot. Load accordingly to total weight of components. Must work up loads seperatly for what your shooting it in.

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