The respected .45 ACP chambering has remained popular throughout its nearly 100 year history; many authorities in the firearms field believe it to be one of the finest examples of the handgun ammunition genre ever developed. Even so, weaponry aficionados have always displayed a fascination with the concept of firearm and cartridge modernization and improvement, in the case of ammunition usually involving additional velocity and muzzle energy. Though it has performed well for many years and is well liked, even the venerable .45 ACP has not proven to be immune from this aspiration.
In 1988 a Gun World magazine article detailed the efforts of staff editor Grennells to update the .45 ACP for the 21st Century, a difficult endeavor due to the inherent design limitations of the veteran round. Introduced in the early 20th century, the .45 auto has a relatively large case capacity which was dictated by the relatively slow burning powders in use at the time of its development; as a result, it operates in the modest range of 19,900 – 22,000 Copper units of pressure (CUP). In contrast, current day magnum cartridges using faster burning modern nitrocellulose powders can produce pressures in the 28,000 – 39,000 CUP range. As it was originally designed for lower pressures, the .45 ACP has relatively thin walls and weak case head and web specifications; it can’t reliably contain increased pressures. The layout of most model 1911 .45 ACP chambers presents yet another challenge in that the case head is not fully supported in the cartridge feed ramp area; pushing the envelope in this critical area with too much pressure risks a catastrophic failure, resulting in a case busting in the chamber. To rule out such a dangerous possibilty, Grennells chose to use brass formed from the stronger and more modern .451 Detonics chambering, shortened to the overall length of the .45 ACP design. Support for the case head was also addressed by adopting a new chamber and barrel design which reinforces the base area of the case. Other areas of the model 1911 pistol design were also strengthened, including the addition of a heavier recoil spring and a strengthened firing pin redesigned to prevent primer material from flowing into the firing pin channel under high chamber pressures. A few manufacturers such as Springfield Armory, Inc. and Heckler & Koch offer models such as H&K’s USP rated to fire the Super ‘right 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.
Texas based Starline Brass company eventually began marketing factory manufactured brass casings for the chambering, taking the round out of the obscure wildcat cartridge realm. In addition, Ace Custom .45’s Inc. of Cleveland, Texas trademarked the .45 Super name in 1994 and currently markets factory .45 Super pistols, as well as gunsmith adaptations of .45 ACP pistols, and .45 ACP conversion kits. Texas Ammunition offers factory loaded ammunition which is marketed by Ace Customs and others.