Brownells BRN-4 Assembled Uppers Shipping Now

GRINNELL, Iowa – Brownells, the leading supplier of firearms accessories and gunsmithing tools, is thrilled to announce the release of the BRN-4® Upper Receiver, now available as an assembled upper. This highly anticipated upper is designed to fit both HK416-style and standard AR-15 lowers.
Assembled from all new components, the BRN-4® Upper comes fully assembled, with the barrel and gas system already installed. All you need to do is add your preferred HK® 416/ MR556 compatible handguard and any 1/2-28 muzzle device, and you’re ready to hit the range.
At the heart of the BRN-4® Upper Receiver is an all new Bolt Carrier Group, featuring a slick nitride finish. The carrier is machined from a single piece of forged 8620 steel and the blot is precision machined from 9310 tool steel, ensuring durability and reliability. Read more











