The 45 Auto +P was introduced by Remington to enhance the performance of the 45 ACP cartridge. 45 Auto + P, always so headstamped, is externally identical to 45 ACP but is loaded to higher pressure, 23,000 psi versus 21,000, increasing velocity by about 100 feet per second with resultant higher energy yield for greater stopping power. 45 ACP +P is safe to use in most 45 ACP handguns, but generates considerably more recoil and reduces the pistol's service life. For these reasons 45 Auto +P is not nearly as popular as standard 45 ACP, but is widely available from manufacturers both large and small.
