Ackley Improved
Also: AI
A family of wildcat cartridges that sharpen the shoulder and reduce body taper of a parent case to gain powder capacity and longer brass life.
Ackley Improved refers to a popular approach to wildcat design developed by gunsmith P.O. Ackley, in which a parent case is given a steeper, usually forty-degree, case shoulder and most of its body taper removed. Those changes increase the internal case capacity for more powder behind the bullet, which can yield a modest velocity gain over the standard chambering.
A clever feature of most Ackley designs is that a factory parent-case round can be fired in the improved chamber to form the new shape, so the shooter gets usable brass and a safe fire-forming load in one step. The sharper shoulder also reduces case stretch and brass flow, which tends to extend case life. Gains are real but generally incremental, so the choice is as much about efficiency and brass longevity as raw speed.