The 38-45 Auto was designed by Bo Clerke of the Armory gun shop, Burbank, CA and was first announced publicly in the October 1963 issue of Guns and Ammo magazine in an article by Howard French. The 45-38 Auto is based on a .45 ACP case necked down to accept standard .38 cal. bullets. Super 38 ACP barrels are reamed out to the new caliber and used in the 45 Colt Auto pistol without any other changes.