The 9×25 Dillon was designed in the 1980’s by Randy Shelly, an employee from Dillon Precision. It is a 10mm auto case necked down to 9mm so that he could get a 9mm cartridge to make major power factor for IPSC, which at that stage was set at 175. The large cases however meant lower magazine capacity as well as significant muzzle blast as well as wear and tear on the guns. When the power factor was reduced to 160 for IPSC, it brought cartridges like the 38 Super Comp into contention and the 9mm Dillon faded away.