The Radian Model 1 Complete Upper Receiver combines precision engineering with premium materials featuring an 18" barrel chambered in 6mm ARC with FDE Cerakote finish. Built with billet machined 7075-T6 aluminum and backed by a Sub-MOA accuracy guarantee with Black Hills Match Grade ammunition.Radian Model 1 Complete Upper Receiver - 18" 6mm ARCBillet machined 7075-T6 upper receiver with M4 feed rampsSub-MOA accuracy guarantee with Black Hills Match Grade ammunitionProprietary extended aluminum handguard with Magpul M-LOK modular mounting systemEnhanced Black Nitride M16 bolt carrier group includedRadian Raptor-SD suppressor-optimized ambidextrous charging handle5/8x24 thread pitch for muzzle devices1:7 twist rate barrel optimized for 6mm ARC performanceFDE Cerakote finish for durability and corrosion resistanceLifetime guarantee from RadianHand-assembled by trained gunsmiths and individually inspected this upper receiver delivers exceptional accuracy and reliability for precision shooting applications. Compatible with AR-15 platform lowers.