BC-15 .223 Wylde Upper 20" Black Nitride Government Barrel 1: 8 Twist Rifle Length Gas System 15" MLOK - $211.82 This BCA AR-15 complete .223 Wylde rifle length upper has a 20" government barrel and a black nitride finish, and features a 1: 8 twist rate, with a rifle length gas system. It includes