The United States military has a long history of adopting so-called wildcat calibers from the civilian world. Hell, the 5.56mm round that fills every M249 belt and M16 magazine has its origins as an experimental varmint round for civilian hunters — the .222 Remington Magnum.
A sniper from the U.S. team makes adjustments to his rifle during the unknown distance event during the Fuerzas Comando competition July 26. (Department of Defense photo by U.S. Army Master Sgt. Alex Licea, Special Operations Command South Public Affairs)
But this was back when the U.S. military’s budget was not only enormous, but had less congressional oversight.