.17 caliber wildcats were conceived by Charles O�Neil as early as 1945. Actual production is credited to P. O. Ackley who started by necking down .30 Carbine cases to .172 shortly there after. Numerous variations have been produced over the years with parent cases being as large as the .22-250 and subsequently a point of diminishing returns was finally realized. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.