Parker Otto Ackley (May 25, 1903 – August 23, 1989)[1] 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.

[2] Ackley began gunsmithing full-time in Oregon in 1936, but was interrupted by World War II.

He was also on the staff of the magazines Guns&Ammo and Shooting Times, and was an instructor at the Trinidad State Junior College from 1946 to 1951, where he did much experimentation in the field of firearms.

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.