Found this info online.
"Manufacturers such as Heckler & Koch (USP and HK45), and Springfield Armory, Inc. currently offer pistols rated to fire .45 Super 'out of the box'. Although they will chamber, the firing of .45 Super rounds in non-rated standard .45 ACP automatics is not recommended, as doing so risks a case failure in the unsupported chamber and at the very least would batter the slide and almost certainly shorten the life of the pistol."