This BCA AR-15 complete .223 Wylde pistol length upper has a 7.5" M4 contour barrel with a parkerized finish, and features a 1:7 twist rate, with a pistol length gas system. It includes a 7 5/16" MLOK rail, an M4 flat-top forged upper receiver, a BCA bolt carrier group, a flash hider, and a rear charging handle. This .223 Wylde upper is compatible with any mil-spec AR-15 lower.