Buffalo Bore is now manufacturing the .45 Auto Rim in four loadings: two standard pressure and two “+P”.
In standard pressure, you can get a 200 gr JHP at a little over 1000 fps (444+ ft-lb) out of a 4″ S&W revolver. The 255 gr hard cast FP is clocking almost 870 fps (410+ ft-lb) out of the same 4″ Smith.
With the “+P” designation, the 200 JHP is sizzling at almost 1200 fps (635 ft-lb) out of the 4″ S&W. The hard cast 255 gr FP is moving at more than 1030 fps (570+ ft-lb). These are amazing numbers. It should be noted that there is not a SAAMI specification for “+P” in the .45 Auto Rim. Consequently, use only a modern firearm with the +P ammunition. Buffalo Bore does state that the +P loads are safe to use in all post-WWII revolvers chambered for the .45 ACP.