TacFire 556 RFL BUILD KIT. 56 Nato M4 contour barrel/nitride; birdcage flash hider w/crush washer; 15" MLOK free float handguard; AR15 5.56/.223/.300AAC stripped billet upper receiver w/M4 feed ramps/.556 Mil-Spec charging handle aluminum w/steel latch; dust cover; AR15 forward assist; AR15 standard receiver end plate; Mil-Spec/commercial castle nut/steel; buffer tube aluminum; AR 15 3 oz buffer w/tube spring; a AR15 standard A2 style black pistol grip/A2 style. Specifications for TacFire SS-RK556-LPK 556 RFL BUILD KIT SSRK556LPK: Manufacturer: TacFire Finish: Black Nitride Color: Black Condition: New Fabric/Material: Aluminum Gun Make: AR Platform Magazine Included: No