The .45 Auto Rim in a .45 Colt revolver
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Driftwood Johnson
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Simple answer. No.
The rim of the 45 Colt cartridge is .060 thick. The rim of 45 Auto Rim is .090 thick. This is because when the 45 Auto Rim cartridge was developed, for the Colt and S&W Model 1917 revolvers, the space behind the cylinder was .030 more than with most revolvers to accommodate the moon clips that 45 ACP was usually clipped to. The .090 thick rim filled up the extra space so the Auto Rim round would headspace properly in a 1917 revolver.
There are modifications that can be made to the rear of the cylinder of a 45 Colt revolver, but as they come from the factory, almost every 45 Colt revolver will only have about .060 behind the cylinder and the .090 thick rim of the 45 AR round will not allow the cylinder to close properly.
I believe Ruger has a model out that will accept both 45 Colt and 45 AR because they have specially machined the rear of the cylinder.
But the standard, run of the mill 45 Colt revolver cannot chamber 45 Auto Rim.
The rim of the 45 Colt cartridge is .060 thick. The rim of 45 Auto Rim is .090 thick. This is because when the 45 Auto Rim cartridge was developed, for the Colt and S&W Model 1917 revolvers, the space behind the cylinder was .030 more than with most revolvers to accommodate the moon clips that 45 ACP was usually clipped to. The .090 thick rim filled up the extra space so the Auto Rim round would headspace properly in a 1917 revolver.
There are modifications that can be made to the rear of the cylinder of a 45 Colt revolver, but as they come from the factory, almost every 45 Colt revolver will only have about .060 behind the cylinder and the .090 thick rim of the 45 AR round will not allow the cylinder to close properly.
I believe Ruger has a model out that will accept both 45 Colt and 45 AR because they have specially machined the rear of the cylinder.
But the standard, run of the mill 45 Colt revolver cannot chamber 45 Auto Rim.
mcb
Member
Ruger has a Redhawk that will accept both 45 Colt and 45 ACP on moonclips. It will not accept 45 Auto Rim. There is a raised rim around the outside of the cylinder that allows the 45 Colt to head space correctly and then the center of the cylinder is recessed to allow the moonclip for the 45 ACP to set down into. The raised rim around the outside of the cylinder to allow the 45 Colt to head space correctly would make the 45 Auto Rim sit to high and you would not be able to close the cylinder.
Found this image of the RH cylinder with a 45 ACP moonclip loaded. Notice the raised rim around the outside of the cylinder. For 45 Auto Rim to work correctly the raised rim would have to be removed.
Found this image of the RH cylinder with a 45 ACP moonclip loaded. Notice the raised rim around the outside of the cylinder. For 45 Auto Rim to work correctly the raised rim would have to be removed.
entropy
Member
Unless it were modified specifically for them, no, for the reasons Driftwood outlined. Then it would only work with .45 Auto Rim. Why would anyone bother wrecking a perfectly good LC?
CraigC
Sixgun Nut
No way, no how. One or the other but not both.
the Real Alpo
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In every modern revolver I've seen, there is a "step" (for lack of a better term) in the cylinder, and the mouth of the cartridge case sits at that step.
This step is what prevents me from loading a 357 into my 38, or a 44 magnum into my 44 special, or (for that matter) a 45 Colt into my 45 ACP.
If I were to face the entire back off my 45 Colt cylinder, so as to allow me to use either 45 ACP or 45 AR in it, while the back of the cylinder would no longer touch the Colt's rim, wouldn't the step still allow it to headspace correctly? The mouth of the case would rest on the step, just like it does when I shoot ACP in my 1917 without using moon clips.
Why wouldn't that work?
This step is what prevents me from loading a 357 into my 38, or a 44 magnum into my 44 special, or (for that matter) a 45 Colt into my 45 ACP.
If I were to face the entire back off my 45 Colt cylinder, so as to allow me to use either 45 ACP or 45 AR in it, while the back of the cylinder would no longer touch the Colt's rim, wouldn't the step still allow it to headspace correctly? The mouth of the case would rest on the step, just like it does when I shoot ACP in my 1917 without using moon clips.
Why wouldn't that work?
CraigC
Sixgun Nut
Because .45Colt is a rimmed cartridge that does not headspace on the case mouth. It gets a firm roll crimp that precludes this from working. That and no gunsmith would ever do such a conversion. You would have to take a lot of material off the rear of the cylinder and that just isn't going to work.
If you just want to use a shorter rimmed cartridge in a .45Colt, there is always the .45S&W and the .45Cowboy Special. Or just rim your .45Colt brass as far as you want.
If you just want to use a shorter rimmed cartridge in a .45Colt, there is always the .45S&W and the .45Cowboy Special. Or just rim your .45Colt brass as far as you want.
Driftwood Johnson
Member
As has been stated, rimmed cartridges do not seat on the step in the chamber. As a matter of fact, the step in the chamber of a revolver is not a square edge, it is a chamfer. And the dimensions are calculated so that the case mouth never quite reaches the chamber step in a cylinder chambered for a rimmed cartridge. You cannot seat a 357 Mag in a 38 Special chamber because the case will bump into the step, but the 38 case mouth never quite reaches the step. It stops slightly short, because the cartridge has head spaced on the rim.
Regarding 45 Auto Rim in a 45 Colt cylinder, there was a guy in CAS a number of years ago who did shave off about .030 from the rear of the cylinder of his revolvers. I think he had Vaqueros, if I remember correctly. He did this so he could shoot 45 Auto Rims in his Vaqueros, but of course once that had been done he could no longer shoot 45 Colt, because there was .030 of slop at the rear of the case rims.
The reason he did this is it turns out 45 Auto Rim, or 45 ACP, is a much more efficient case for light loads. Some CAS shooters shoot loads so light in the cavernous 45 Colt that the powder does not burn efficiently. But with the much smaller interior space of the 45 Auto Rim, light loads can be much more effective and the powder will burn completely.
The 625 takes .45 ACP with or without clips and .45 AR.
I load both ACP and AR on my Dillon by changing only the shell plate. I shoot .45 Colt and .45 AR in my Ruger NMBH by switching cylinders. The .45 ACP cylinder has been trimmed to allow use of .45 AR in addition to the standard.45 ACP. I prefer.45 AR in both the Ruger and S&W 625.
I load both ACP and AR on my Dillon by changing only the shell plate. I shoot .45 Colt and .45 AR in my Ruger NMBH by switching cylinders. The .45 ACP cylinder has been trimmed to allow use of .45 AR in addition to the standard.45 ACP. I prefer.45 AR in both the Ruger and S&W 625.
Driftwood Johnson
Member
So did the original Model 1917. But neither will accept 45 Colt. I have a Model 1955 Target chambered for 45 ACP. It too will accept 45 Auto Rim, but not 45 Colt, because of the rim situation.
mcb
Member
That is crazy talk. The whole point of a 625 is to have short fat round nose cartridges on a full moonclip making it one of, if not the, fastest reloading revolvers out there. 45AR makes no sense at all to me. MOONCLIPS RULE.
CraigC
Sixgun Nut
.45AR makes total sense if you want to be able to shoot that sixgun without fooling with moon clips.
cowboy77845
Member
OH boy! I got 2 questions answered about the 625 and Ruger Redhawk. What a great forum.
I was reading through some back issues of Shooting Times and found this on the .45 Auto Rim. I believe it covers several of the issues brought up in this thread.
And this from Starline on their .45AR brass:
This implies their .45AR brass is tested to .44 Mag pressure levels. Incredible.
The Peters solution was to make a .45 Auto case with a rim. The rim is almost 50 percent thicker than the rims of the .44 Special and .45 Colt. This odd rim fills the large rear cylinder gap that is cut to accommodate the .45 Auto’s rim plus a 0.050-inch clip. Peters also opted for a lead 230-grain RN bullet, which was deemed more appropriate to revolver shooting.
There are many of these revolvers still in shooting condition, but I hear people complaining they are not very accurate. Assuming the sixgun has not been abused, it can shoot as well as any other firearm, and better than many.
The Pressure Question
The .45 Auto Rim’s pressure assignment is 3,000 CUP less than the .45 Auto. This appears to be an accommodation to the soft factory lead bullets, not the strength of the revolvers. Peters chose to load the .45 AR with a soft lead bullet with a deep, hollow base and a thin skirt to better grip the shallow rifling. The downside is that typical .45 Auto pressures can deform the skirt as the bullet leaves the muzzle and destroy the accuracy.
The heavy rim of the .45 Auto Rim cartridge (right) is the thickness of a .45 Auto’s rim (left) plus the thickness of a half-moon clip.
The revolvers were designed for standard .45 Auto, so there should be no issue with factory ammo or handloads that remain within .45 Auto pressures–18,000 CUP or 21,000 psi, depending on the test system.
Read more: http://www.shootingtimes.com/ammo/ammunition_the_45_auto_rim_022811/#ixzz4ytmrhqCG
And this from Starline on their .45AR brass:
This implies their .45AR brass is tested to .44 Mag pressure levels. Incredible.
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mcb
Member
Still sounds like crazy talk. Why would one not want to use moonclips? I can think of no good reasons...
If1HitU
Member
I learn something new here everyday.
CraigC
Sixgun Nut
.45Colt is used up to 50-55,000psi.
You know all that time you spend loading and unloading moon clips? Some people don't wanna do that.Still sounds like crazy talk. Why would one not want to use moonclips? I can think of no good reasons...
CraigC, but the Shooting Times article states:
Is Starline simply going above and way beyond the call of duty? Their Auto Rim brass meets .44 Mag level pressure tests.
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CraigC
Sixgun Nut
IMHO, no modern case is going to give up the ghost at 36,000psi. Starline's brass is very good but it's folly to think that any case can't survive at higher than SAAMI pressure standards. Cases are simply not designed to be 'just' strong enough. Make it just strong enough and it probably wouldn't even be reloadable.
mcb
Member
A good mooner and an old hollow golf club handle. Fast in fast out. Not to mention you can load them long before the range trip or match and take your time unloading after you get home.
MOONCLIPS RULE !
CraigC
Sixgun Nut
Like I said, not everybody wants to do that.
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