The Radian Model 1 Complete Upper Receiver represents precision engineering at its finest featuring an 18" barrel chambered in 6mm ARC with OD Green Cerakote finish and sub-MOA accuracy guarantee with Black Hills Match Grade ammunition.Radian Model 1 Complete Upper Receiver for AR-1518" barrel with 1:7 twist rate in 6mm ARCBillet machined 7075-T6 upper receiver with M4 feed rampsOD Green Cerakote finish for durabilityProprietary M-LOK aluminum handguard with anti-rotation pinEnhanced Black Nitride M16 bolt carrier groupRadian Raptor-SD suppressor-optimized ambidextrous charging handle5/8x24 threaded muzzle for suppressor compatibilityLifetime guarantee from RadianHand-assembled by trained gunsmiths and individually test-fired this complete upper delivers exceptional accuracy and reliability for precision shooting applications hunting and competitive use.