.45AutoRim: The Great Survivor

[Mr.Revolverguy]

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".


Complete Review Here - Stop by and leave comments to let me know what you think.

Blessed and Merry Christmas to All.

 

[Rodentman]

I agree completely! I reload the 45AR and have a lot of fun shooting it.

 

[jell-dog]

I agree completely! I reload the 45AR and have a lot of fun shooting it.

Rodentman,
What die set do you use?
And any other information about reloading this cartridge would be greatly appreciated!
MERRY CHRISTMAS!
jell-dog

 

[Ditchtiger]

Rodentman,
What die set do you use?
And any other information about reloading this cartridge would be greatly appreciated!
MERRY CHRISTMAS!
jell-dog

Not counting the shell holder everything is the same as .45acp
Though there are 255gr. loads for the auto rim.
I got my 625 new back in 1989. And 50,000 rounds later it's still my favorite.
Mostly lite lead loads to make the powder last.

 

[krupparms]

This last year I got almost 1,000 pieces of .45AR brass. About 350 rounds were loaded. I have a nice S&W 1937 Brazilian .45acp. It is a great piece to carry in the woods. I plan to reload for this round as it is fun to shoot & works for SD or HD. I can use .45acp.for plinking & use the .45AR. for the woods. I really like that I can use this load in speedloaders. This is one of the most underestimated rounds out there! This round is great for .45acp. revolvers! It should be way more popular than it is!

 

[MI2600]

After maybe two range trips, I was tired of fumbling around with moon clips for use in my 1917s. The clips and two different "tools" made for loading them now reside in my gun parts box.

I bought some AR brass online, and the only ACP I load now are for my semi-autos.

 

[Driftwood Johnson]

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.

 

[Lucky Derby]

.45 Cowboy Special? Never heard of that one. I presume it has something to do with CAS?

 

[Rodentman]

Yes same dieset as stated above. Honestly I didn't realize this round was not used much, although I should have figured that out. Brass was plentiful, guy at the GS recommended it when I bought my 625JM, so off I went...

 

[StrawHat]

Lucky Derby


.45 Cowboy Special? Never heard of that one. I presume it has something to do with CAS?

Yep, it was developed to allow a much shorter case to be fired in a 45 long Colt. Basically, a 45 ACP with a 45 long Colt rim. Same capacity as the ACP and loaded with ACP dies. Also used in the 45 long Colt rifles (Winchester and Marlin or copies) and you can get a bunch into a magazine!

I have used the 45 AR in my many S&W revolvers. Again loading with 45 ACP dies but a different shellholder. I use the AR brass for loads I do not want to get into a 1911, ie., full wadcutter bullets, or heavier than "normal" loads.

I also use the ACP brass with moon clips, either 3 or 6 round, and find them to good advantage also.

Many different ways to defur a feline.

 

[Driftwood Johnson]

Howdy Again

StrawHat is correct about the 45 Cowboy Special. Developed to get around the issues I mentioned earlier about extra air space in the 45 Colt when loaded with Smokeless. Same rim as the 45 Colt, same length and interior dimensions as the 45 ACP. 45CS can be loaded with any standard 45 ACP load, and fired in any revolver chambered for 45 Colt. However if you want to shoot them in a lever gun you will have to modify the carrier to feed the much shorter round properly.

 

[jell-dog]

45 AR revolver ammo

Obviously this IS a cartridge that has a dedicated following!
Thanks to MrRevolverGuy and all who replied to this thread
Your comments have motivated me to research the 45AR further and start looking for a 45auto revolver in GREAT "shooter" condition.
Any suggestions for 45ACP revolver models to get/stay away from will be greatly appreciated!
I may have found that "new gun, cartridge" to ease my "GOTTA get something new itch"
jell-dog

 

[highlander 5]

I use both 45 acp and 45 AR in my 2 625s and as of this point the only bullet I've not used in the 45 AR is the 250 gr. full wad cutter that I cast for 45 Colt/Schofield.

 

[Deaf Smith]

In my 625 I use Auto Rim only for the hot loads that I know are not safe for my 1911s.

That way it's easy to keep the right ammo in the right gun. I have no old 1917s so this works.

250gr SWCs and JHPs are easy to load and not hard to get 1000 fps from my 3 inch bbl. 625.

My baby is at the top along with my 66-2 and 640.

Deaf

 

[jell-dog]

GREAT LOOKIN' set of revolvers Deaf Smith!
Watch out the moderator doesn't ding you for posting gun "porn"
(hey, just kidding mod )
jell-dog

 

[Deaf Smith]

Well I have a 'few' more...

Deaf

 

[jell-dog]

Deaf Smith Well I have a 'few' more...

Deaf Smith,
Well, I guess you do!
Now I feel revolver envy
jell-dog

 

[Kaeto]

I load .45 AR for my shaved .455 Webley MK VI.

 

[Dframe]

I use both in my revolvers so chambered. They all run great. Dispensing with the moon clips is sometimes handy. But aside from loading and unloading the clips at home, I find them to be VERY handy especially in the field where I've never lost a round of brass.

 

[Jim K]

FWIW, the SAAMI pressure spec for the .45 AR is 15kpsi, vs 21kpsi for the .45 ACP.

Jim

 

[Mr.Revolverguy]

Jim,

Not really but I know what you are getting at. Meaning the SAAMI spec is 15k CUP which is different than PSI. In my research you find in cartridge loading books from the historians or experts that the reason the SAAMI pressure spec is lower is due to originally how Peters loaded the cartridge with a soft lead bullet.

Some of the reloading books adhere and some of them give caution. For example Speer specifically calls out the SAMMI spec for AutoRim is 15KCUP but state all of their 45AR loads are within 45Auto pressure of 21kPSI.

It is safe to use 45 Auto factory ammo / SAAMI spec in today's revolvers. I would not use +P or +P+, if I need that kind of power I just always go up to the next caliber anyway. Chose the right pistol and ammunition for the job.

Respectfully,
Mr.Revolverguy

 

[bonza]

The WW1-issued M.1917 revolvers were made for use with the .45ACP in moon clips, & this is how they were used throughout that conflict. The .45AR cartridge wasn't introduced until 1920, by Remington-Peters.
Like another poster here, I have used .45 Auto Rim brass in a shaved .455 Webley, but it should be stressed that .45 Auto Rim factory ammo (or reloads of factory level, or higher) should NOT be used in these revolvers, as that would be akin to using a steady diet of .455 proof loads. When using .45AR brass in a .455 Webley you should only use .455 loading data. Also, for better case life use .455 Webley dies (Lee makes a very economical set), along with a .45AR shell holder, rather than .45ACP/AR dies as they will oversize the brass.

 

[Mr.Revolverguy]

Good post Bonza,

Not to split hairs but Remington purchased Peters around about 1938 and 45AR was released late 1920 early 1921. So the 45AR is strictly developed by Peters alone.

 

[Kaeto]

The WW1-issued M.1917 revolvers were made for use with the .45ACP in moon clips, & this is how they were used throughout that conflict. The .45AR cartridge wasn't introduced until 1920, by Remington-Peters.
Like another poster here, I have used .45 Auto Rim brass in a shaved .455 Webley, but it should be stressed that .45 Auto Rim factory ammo (or reloads of factory level, or higher) should NOT be used in these revolvers, as that would be akin to using a steady diet of .455 proof loads. When using .45AR brass in a .455 Webley you should only use .455 loading data. Also, for better case life use .455 Webley dies (Lee makes a very economical set), along with a .45AR shell holder, rather than .45ACP/AR dies as they will oversize the brass.

I do load to .455 specs in both my .45 AR and ACP. I don't have any guns that shoot ACP other than the Webley.



(and no the picture is not reversed. I'm left handed, and I'm trying to make a ambidextrous barrel latch to replace the original one.)

 

[ApacheCoTodd]

Loves me some AR... and moon clips as well.

1/2 moon, full moon, whatever - I like 'em.

But Auto-Rim, they're just too cool for 1911 school!

Look cool, are particular about the firearm company that they keep and make a distinct sound when (if) they hit the cement after ejecting.

My preferences for use though, run along lanyard loop lines: Enfield, Smith & Wesson and Colt.