45AutoRim: The Great Survivor

M

Mr.RevolverGuy

New member
The .45 AutoRim is a cartridge lucky to be in existence. Due to the lack of 1911's as America prepared to enter WWI Smith & Wesson and Colt produced revolvers chambered for the .45ACP. These new revolvers were designated as the 1917 by the Army. Even though the 1917 revolver was derived out of what some say is necessity and others say unpreparedness for the war it is clear the .45AutoRim was an afterthought and yet still remains in existence today. It is possibly the least known and least popular revolver cartridges still sold and produced by many ammunition manufacturers. Everything about this cartridge breaks the rules of ammunition development. Revolvers typically introduce new cartridges or are adapted and retrofit to existing cartridges. It is not ironic however that I can often be found on the range when shooting pistols to always be accompanied by a Smith & Wesson model 625 and a box or two of .45 AutoRim ammunition. I find it very versatile fun to shoot, easy to reload and I never ever lose a piece of brass which is one of the attributes that make it a "Great Survivor".
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The fat rim is to take up the space usually occupied by the half moon or moon clip.

Wonderful cartridge which can be loaded a bit higher than the ACP because of its stoutness and the use of a revolver rather than an auto.

I may be mistaken but I think HKS used to or still does make a speedloader for it.
 
I had a M25 Smith years ago and had a great time loading the AutoRim. Back then Remington sold a 230gr lead round nose that shoot pretty good. I used to load the Speer 250SWC over Unique, very cool cartridge.;)
 
It is possibly the least known and least popular revolver cartridges still sold and produced by many ammunition manufacturers.
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As much as I like the old warhorse, I'm not sure about the "produced by many ammunition manufacturers" part. AFAIK, only Starline still makes the brass and a couple of boutique manufacturers, Buffalo Bore and Double Tap load it. None of the majors still do. Remington dropped it some time ago.
 
Perhaps a dumb question, but are there any revolvers that are chambered for .45 AR only (i.e., cannot be used with .45 ACP and clips)?
 
"Even though the .45 AutoRim was derived out of what some say is necessity and others say unpreparedness for the war it is clear it was an afterthought yet still remains in existence today."

The Auto-Rim cartridge was actually developed by Peters Cartridge Company and introduced in 1920, not for military purposes, but for American consumers who either obtained military surplus M1917s or purchased commercial variations.

Wikipedia says that the cartridge was developed by Remington-Peters, but that's impossible, given that Remington didn't purchase an interest in Peters until 1934, when that company almost went out of business due to the effects of the Great Depression.
 
Mike,

I think we are saying the same thing so possibly I could have written it in a different way I see where it could be confusing.

"The Auto-Rim cartridge was actually developed by Peters Cartridge Company and introduced in 1920, not for military purposes, but for American consumers who either obtained military surplus M1917s or purchased commercial variations."

Here is what's in my article.
The afterthought of the 45 AutoRim is evident in that it was introduced a half a decade after the 1917 revolvers by Peters Cartridge Company. Peters developed this cartridge to fire in revolvers without clips, yes clips. Originally “half moon clips” were developed which allows the rimless 45ACP to be easily extracted from a revolver, it also is very important in providing the proper headspace to ensure reliability.
 
Perhaps a dumb question, but are there any revolvers that are chambered for .45 AR only (i.e., cannot be used with .45 ACP and clips)?
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I suppose such a thing might be possible if you tried hard enough, but the 45 AR was meant to be used in revolvers that were initially designed to take 45 ACP and clips. That's why the rim is so unusually thick.

So it could be done but nobody's done it.
 
Howdy

A few years ago Mike Venturino wrote an article for one of the magazines extolling the virtues of the 45 AR round. A much better round for Smokeless powder than the old 45 Colt. 45 Colt was developed during the Black Powder era and had to have enough case capacity to contain enough powder to do the job. But when loaded with Smokeless powder, the much smaller volume of Smokeless leaves a great deal of empty space in the cartridge. That large amount of space can lead to pressure problems and erratic ignition, particularly with light loads. The 45 AR is just the right size for the volume of powder needed with Smokeless. No excess empty space to cause pressure problems. And of course, you don't need to fool with moon clips.

I load 45 AR with a standard 45 ACP die set. I have a WWI era S&W Model 1917 and two Brazilians that I shoot with 45 AR. I also have a Model 1955 Target that I have not yet fired with 45 AR. Must do that in the spring.

Here is a photo showing the comparative sizes of several 45 caliber cartridges. Left to right they are 45 Colt, 45 Schofield, 45 Cowboy Special, 45 AR, and 45 ACP. Case size is a pretty good indicator of internal case capacity.

45C45Sc45CowboySP45AR45ACP.jpg
 
Has Remington actually dropped the .45AR? Or have are they just doing "seasonal" production? ("seasonal production" in this case means doing a production run irregularly, such as every two or three years..)

I think the reason the round has survived is that essentially, the guns have survived, and more modern guns cut to use ACP cases and clips will generally use Auto Rim cases as well.

Not every gun will, though. I haven't run into a factory gun where this was the case, but I have found some of the conversions that don't like the AR case.

I have a Webley Mk VI that has been "shaved" to use ACP brass in half moon clips. It works wonderfuly, with the S&W clips I have. It works with some nameless 2-rnd clips I got (1/4 Moon??:rolleyes:) but it will not work with any full moon clips I have tried, nor will it work with Auto Rim cases. They are just too thick for the clearance the gun has.

Auto Rim cases chamber fine, and the gun closes normally, but they fit too tight against the recoil shield, the cylinder binds and cannot be turned. Other guns (probably cut by someone else) work fine with AR cases. (WARNING!!! NO WEBLEY should be fired with .45acp or .45 Auto Rim AMMUNITION!!! USE ONLY THE CASES to load ammo suitable for .455 Webley revolvers. Standard ammo pressures in .45acp/.45AR are proof level loads (or above) in .455 Webley guns!!!)
 
Quincunx asked:
Perhaps a dumb question, but are there any revolvers that are chambered for .45 AR only (i.e., cannot be used with .45 ACP and clips)?
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No, but conversely the Ruger convertibles chamber the .45 ACP but won't chamber the .45 AR round. There is not enough headspace clearance for the thick rim.

There have been attempts to counterbore the cylinder to accomodate though.

Bob Wright
 
I can't imagine anyone reworking any gun to chamber a rather obscure cartridge like the .45 AR, but folks do a lot of things I can't imagine. There would be little point in a Ruger SA, because there is no need for extraction, the Ruger having a rod ejector.

Many of the "shaved" Webley revolvers will accept and fire the .45 AR, but I would strongly advise against using .45 AR or .45 ACP factory ammo in any Webley. The cylinders have been known to burst with factory .45 ACP and while the factory .45 AR is loaded to a bit lower pressure, it also is much higher pressure than the .455 for which those guns were made.

Jim
 
Hi
I have fired the Remington .45 AR cartridge for years. I started off by buying 200 Remington primed cases to use to load for it. Joesph Wesson was the designer of Moon clip's for use in their Model of 1917 .45 Hand eject revolvers.I Much Prefer to shoot the Remington AR cases as Moon clip's to me are a P.I.T.A. to use. I do know that Loaded right it is very acurate as this six shot group shot @ the 25 Yard line show's it to be. Regards, Hammer It



S_W_45_Target_revolver_004.jpg
 
Has Remington actually dropped the .45AR? Or have are they just doing "seasonal" production?
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There's no mention of it on Remington's website and neither Midway nor Ammo to Go show a Remington offering. Usually seasonal offerings still show up on a manufacturers list.

Corbon loads it as well.
 
An interesting side note about the .45 Auto Rim, many loading manuals (particularly the old ones) show max loads for the Auto Rim heavier than the .45ACP.

The usual explanation given is the "greater strength" of the revolver vs. the 1911.

While I won't say this statement is not accurate, I don't think its adequate. Because when you say strength, what is usually thought of is strength in terms of blowing up, cracking, suffering damage, etc.

But with the 1911 design, the usual limiting factor not just the physical strength of the metal. Autoloaders are a balancing act. Max pressure, and pressure over time are important. In a revolver its just max pressure.

I believe that the mechanism of the 1911 will handle the heavier loads, from a pure strength standpoint, but what it won't do (as normally set up) is handle those loads and function normally as an autoloader.
 
I have a custom Blackhawk that has a 2nd cylinder made just for the Autorim cartridge... I happened down the Autorim path purely by accident, when I was able to buy a 5 gallon pail of new cases for scrap price... well... I had to do something with them, so I 1st bought a Colt 1917 revolver, then had a cylinder made for my Blackhawk...

since I load Trailboss for my CAS 45 Colt rounds, I use that powder for the Autorim for the 1917, to treat the old gal nicely... I currently have some hotter loads for the Blackhawk, but really never put the Autorim cylinder in, as with handloads, I can do anything I need with the 45 Colt cylinder...

still an interesting cartridge non the less :)
 
I guess I can understand reworking a gun to use that many cases.

Years ago when fountain pens were on the way out, I had an 8 oz jar of ink. I kept buying fountain pens just to use up the ink. I finally threw both the pens and the ink away and went to ball pens like the rest of the world.

BTW, the SAAMI pressure spec for the .45 AR is 15k psi, vs 21k for the .45 ACP, so the factory .45 AR is loaded a lot lighter than the .45 ACP.

Jim
 
Remington put the loaded round ok n the subject to available stock (their way of saying we are dropping it) in 1992 or 1993 when I was on Rifleman staff.
 
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