The MPX Copperhead features a monolithic Elite Series Cerakote finish upper receiver and a 4.5" barrel with integrated muzzle brake. The SIG MPX redefines the submachine gun category with a new level of operator safety, in-field adaptability and proven reliability in the harshest environments. It features dual-sided selector switch, magazine release, charging handle and bolt release. The SIG MPX operates from a fully-closed and locked rotating bolt, offering enhanced reliability and safety in use. A short-stroke gas piston allows the SIG MPX to run all weights and brands of 9mm ammunition with no adjustments to the gas valve.