Brn-4 Piston Upper Receiver Kits - Brn-4 10.4'''' Upper Receiver Kit W/ Medium Profile Barrel

The Brownells BRN-4 Piston Upper Receiver Kits - Parts Kit New Production Brownells and surplus HKA(R) Components Utilizing new production Brownells BRN-4 Bolt Carrier Groups and Barrels, the unassembled BRN-4 Upper Kits feature HKA(R) 416 compatible components, in an affordable package. The heart of this bundle is the new BRN-4 Bolt Carrier Group, with nitride finish. This BCG is designed to be compatible with 416 components, such as the genuine 416 stripped upper this kit is paired with. The BRN-4 barrel is new production as well, manufactured by Faxon for Brownells. These barrels have a 5.56x45mm NATO chamber and have a 1-7 twist. The medium profile is slimmer than classic Mfg: Brownells