Saturday, February 05, 2011

.45 Auto Rim

The .45 Auto Rim (AR) is the .45 ACP with a heavy/thick rim made up to meet the demand for a rimmed cartridge for the 1917 revolvers developed for emergency issue in WWI.  Likewise it can be used in all the Smith and Wesson revolvers chambered for the .45 ACP.  Use of the rimmed cartridge eliminates the need for the "moon clip" and is easier to manage for sporting use.   Factory ammo is often loaded with a 230 grain round-nosed bullet mimicking the 230 grain "ball" load for the .45 ACP but several manufacturers produce standard pressure and "+P" loads using the 255 grain bullets, both Keith and a more traditional "RN" style. There are also loads using 200 grain JHP loads. Such loads will equal standard pressure (i.e. NOT for Ruger New Model Blackhawk) .45 Colt loads.

Since I bought my 25-2 Jovino Effector type revolver from my friend John H_____ I've been considering using the .45 AR for the first cylinder full in daily carry.  I've been most interested in use of the 250 grain Keith bullet.

To start I bought a box of loaded .45 AR at a gun show and then ordered 200 pieces of Starline brass. I quickly found it necessary to order a roll-crimp seating die for my die set in order to properly crimp the Keith type bullets. It was also necessary to order the shell holders for both the press and the Lee AutoPrime due to the Auto Rim's unique rim thickness. It simply isn't practical to use or modify anything else. I have a lot of Unique because I use it in a lot of cartridges (.32 S&W, .38 Special, .41 Magnum, .44 Special, .44 Magnum, .45 Colt) so that is what I want to use.  It would be reasonable to use some others like Universal, W231/HP38, PowerPistol and such but I'm going to start with Unique and change only if I can't get the performance I want.

LOAD DATA (in research)

BulletWeightPowderWeightVelocityEnergy
Keith255 gr.Unique7.0 gr.unknownunknown
Keith255 gr.W231 or HP386.0 gr.unknownunknown
FMJRN230 gr.Unique6.5 gr.unknownunknown

Links:
- Corbon .45 Auto Rim 160-gr. DPX at Highpowers and Handguns
- SMITH & WESSON'S 625-2 .45 AUTO RIM by JOHN TAFFIN

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