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**44 AMP** · May 29, 2013, 12:59 PM

How much difference is .007"?

I'm sure you could get your Redhawk cylinder cut, but I have to wonder why?

Take a look at the cartridge specs. Cases based on the .45ACP (including the Auto Rim and the .45WinMag) all have a case mouth diameter of .473".

Cases based on the .45 Colt ("Long" Colt, Schoefield, .454, .460, etc) have case mouth diameters of .480".

So, while the moon clip system will handle your headspace issues in the DA revolver, the .45 Colt (.454 etc) chambers are already oversize for the .45ACP.

It would probably work, meaning the ACP rounds would fire, but the .007" larger diameter chamber would mean that the cases would swell a lot. Maybe enough to split. Gas seal between the chamber walls and case would be, "iffy", IMHO.

And, I'm pretty certain that accuracy would be poor. Firing the short round in an oversize chamber (both in diameter and in length) means the bullet has a lot of opportunity to enter the barrel less then "square" with the bore.

SA revolvers use a separate cylinder for the .45ACP, because of the headspace system, AND because it lets them fit the chamber to the cartridge properly. Because of the difference in diameter between the .45 Colt class cases and the .45ACP class, one cylinder cannot fit both properly.

Its your gun, do what you want, but to me, its not worth the cost of the conversion for the utility gained. If your intention is to have one gun that you can still use if you have .45acp ammo and run out of everything else, I believe that it would still go bang. However, I think you would not be entirely happy with the results, beyond that.

TO me, it makes more sense to just get a .45acp revolver to have as backup if/when you are out of Colt (and other) ammo.

May 29, 2013, 12:59 PM	#2
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,811	How much difference is .007"? I'm sure you could get your Redhawk cylinder cut, but I have to wonder why? Take a look at the cartridge specs. Cases based on the .45ACP (including the Auto Rim and the .45WinMag) all have a case mouth diameter of .473". Cases based on the .45 Colt ("Long" Colt, Schoefield, .454, .460, etc) have case mouth diameters of .480". So, while the moon clip system will handle your headspace issues in the DA revolver, the .45 Colt (.454 etc) chambers are already oversize for the .45ACP. It would probably work, meaning the ACP rounds would fire, but the .007" larger diameter chamber would mean that the cases would swell a lot. Maybe enough to split. Gas seal between the chamber walls and case would be, "iffy", IMHO. And, I'm pretty certain that accuracy would be poor. Firing the short round in an oversize chamber (both in diameter and in length) means the bullet has a lot of opportunity to enter the barrel less then "square" with the bore. SA revolvers use a separate cylinder for the .45ACP, because of the headspace system, AND because it lets them fit the chamber to the cartridge properly. Because of the difference in diameter between the .45 Colt class cases and the .45ACP class, one cylinder cannot fit both properly. Its your gun, do what you want, but to me, its not worth the cost of the conversion for the utility gained. If your intention is to have one gun that you can still use if you have .45acp ammo and run out of everything else, I believe that it would still go bang. However, I think you would not be entirely happy with the results, beyond that. TO me, it makes more sense to just get a .45acp revolver to have as backup if/when you are out of Colt (and other) ammo. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.