The U.S. has experimented with about every caliber of ammunition between 10mm and 30mm over the years, not including the various "inch" designation experimentals. Photo 1 shows l-r 10x108mm high velocity, headstamped FA 61; 12.7x108mm APDS ,headstamped 88; 15x99 spotter, headstamped FA 60; 16x98mm Vega, HE, for the Vega aircraft gun; 20x158mm T5E2 case; 23x133mm Smith & Wesson Bushmaster candidate, only 1500 cases made; 23x139mm Amron made Bushmaster variation; 23x159mm unknown Bushmaster candidate case.
Photo 2 l-r 25x145mm AAI candidate Bushmaster TPT; 26x130mm Colt Industries Bushmaster candidate; 27x70mm US Air Force T142 Practice, aluminum case; 27.5x160 Aerojet Bushmaster candidate; 27.5x140 Aerojet Bushmaster first design case; 30mm semi-caseless.
Can anyone else fill in other metric calibers between 10 and 30mm the U.S. has played with over the years?
Photo 2 l-r 25x145mm AAI candidate Bushmaster TPT; 26x130mm Colt Industries Bushmaster candidate; 27x70mm US Air Force T142 Practice, aluminum case; 27.5x160 Aerojet Bushmaster candidate; 27.5x140 Aerojet Bushmaster first design case; 30mm semi-caseless.
Can anyone else fill in other metric calibers between 10 and 30mm the U.S. has played with over the years?