[fred cook]

Originally Posted by Jeff Higgins

It's called ".45 Auto Rim". It's just the .45 ACP case formed with a rim so it can be used in revolvers without the need for the moon clips. It can be very hard to find, and expensive when you do find it. Relatively few shooters even know about it, much less use it.

One would think, since S&W periodically makes revolvers chambered in .45 ACP, that there would be a market for Auto Rim ammo. They are currently producing one, as a matter of fact, in some Jerry Miculek special edition of some kind. Such is not the case, however, since the new .45 ACP revolvers are chambered a bit differently than the old wartime guns. The new ones head space on the case mouth, just like the auto pistols do, rather than on the rim like other revolvers. This makes them usable with standard .45 ACP cases without moon clips. Extraction remains a problem, with no rim for the ejector star to grab, but cases will probably just fall out without using the ejector. Or just pop them out with a pencil.

In my buddy's case, being a hand loader, when he found the brass he was pretty much set for life. It uses the same component bullets, same powders, same primers, and same loading data as the .45 ACP, so it's really easy to reload for it. The brass is the hangup.

Found this on Gunbroker this morning. 100 pieces of empty auto rim brass for $24.00! https://www.gunbroker.com/item/779374633