AR15 4.5" Upper Receiver .338 ARC Bolt Action

*30% less weight with split rail than regular MLOK! This AR-15 Complete .338 Arc Bolt Action Style pistol length upper has a 4.5" heavy barrel with a parkerized finish, and features a 1:8 twist rate. It includes the MLOK split rail, an M4 flat-top 7075 billet aluminum upper receiver, a bolt carrier group, a flash hider, and a right-side bolt action style charger. This .338 Arc upper is compatible with any mil-spec AR-15 lower.