.277 SIG Fury was developed for use in the US Military's XM5 rifle as well as the XM250 squad automatic weapon. It is available with an all-brass case for its training and hunting ammo with operating pressures in the 50,000 PSI range while the military has bi-metal cased loads for use down-range. These hybrid cases include a steel rim and a brass case body that allow for operating pressures of 80,000 PSI
