Brn-4 Upper Receiver Build Kits - Brn-4 Upper Receiver Build Kit, 16'''' Heavy Barrel

Build your own upper receiver kit! The BRN-4A(R) is now available as an Build Kit. Simply add your preferred HKA(R) 416 compatible handguard and any 1/2-28 muzzle device, and you're ready to build! Includes all of the main components, plus a BRN-4A(R) barrel nut wrench to properly install the barrel. The core of the BRN-4A(R) Upper Receiver is an all new Bolt Carrier Group, featuring a slick nitride finish. The carrier itself is machined from one piece of forged 8620 steel. The bolt is precis