page_title: P.O. Ackley
section_title: Other Research
hierarchical_section_title: P.O. Ackley / Other Research
caption_attribution_description: Ammunition picture of .243 Winchester and .243 Ackley Improved cartridges
context_page_description: Parker Otto Ackley was an American gunsmith, barrel maker, author, columnist, and wildcat cartridge developer. The Ackley Improved family of wildcat cartridges are designed to be easily made by rechambering existing firearms, and fireforming the ammunition to decrease body taper and increase shoulder angle, resulting in a higher case capacity. Ackley improved not only standard cartridges, but also other popular wildcats, and was the first to create a .17 caliber centerfire cartridge.
context_section_description: Ackley was not just a wildcatter, he was a researcher as well, often testing firearms to destruction in the search for information. He also produced a number of experimental cartridges, not intended to be practical, but rather to test the limits of firearms.  One of these experimental cartridges was the .22 Eargesplitten Loudenboomer. This humorously named cartridge was developed by Ackley for Bob Hutton of Guns & Ammo magazine, and was intended solely to exceed 5,000 ft/s (1,500 m/s) muzzle velocity.  Ackley's loads only managed 4,600 ft/s (1,400 m/s)(Mach 4.2), firing a 50-grain (3.2 g) bullet. Based on a .378 Weatherby Magnum case, the case is impractically over-capacity for the bore diameter, and so the cartridge remains a curiosity. The advent of new slower-burning smokeless powders may have changed the equation.
  Another humorous round, the .17 Flintstone Super Eyebunger, based on the .22-250 necked down to .17 caliber, has been used by Australian  gunsmith Bill Hambly-Clark, Jr. to achieve velocities of 4,798 ft/s (1,462 m/s) out of a 52-inch (1,300 mm) barreled gun.
  NOTE:
  The term "Ackley Improved" has been applied by various gunsmiths conceptually to many cartridges not extant during P.O. Ackley's  lifetime. 
  By P.O. Ackley's definition of Improved, a firearm so chambered must be capable of shooting the factory original round, also such cartridge case either necked up or down to a different bullet size, without stretching the case.  To accomplish this, the chamber for a rimless bottle necked "improved" cartridge must be somewhat shorter in the body than the original so that there is no headspace when the round is chambered.
caption: A .243 Winchester (right) beside the Ackley Improved version; note that only the shoulder angle is changed to the sharper shoulder angle typical of the Ackley Improved cartridges. In this instance the shoulder diameter of the Improved normally remains the same as the original case at .456"-.457" with no significant change in body taper. However, minor variations exist with some drawings showing a slightly larger .460" shoulder diameter.
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