Buffalo Bore Ammunition 31A20 Standard Pressure 45 Auto Rim 255Gr Handgun Ammo - 20 Rounds - This heavy 45 Auto Rim standard pressure load utilizes high quality Starline brass with flash suppressed powder to shoot in the dark without blinding yourself. It is the ballistic equivalent of +P 45 ACP loads, yet they operate at standard 45 ACP pressures. These 45 Auto Rim loads are safe to use in any 45 ACP revolver that is in normal operating condition, including any model 1917 Colt or S&W revolver.