Overview Product Description Brn-601 20'' Upper ReceiverCartridge : AKK_5.56 x 45Color : GrayContour : LightweightFinish : AnodizedMake : BrownellsMake/Model : Brownells|BRN-601Model : BRN-601Muzzle : 1/2-28Style : CompleteTwist : 1-12 Product Videos Custom Field Product Reviews