The Rock River Arms .458 SOCOM 16" Complete Upper Assembly is a robust addition to your firearm featuring a precision-engineered 16-inch chrome moly bull barrel with a 1:14 twist rate. Designed for high performance this upper assembly includes the RRA Beast Brake muzzle device providing superior recoil management. Its low-profile gas block ensures reliability while the 13-inch M-LOK compatible lightweight aluminum free float rail offers versatility for accessory mounting. Complete with a bolt carrier group and charging handle assembly this upper receiver is crafted to deliver durability and accuracy for your shooting needs.