Brownells BRN-4 Piston Upper Receiver Kits:

An Affordable Way To Own a Legend!

The HK416 is perhaps most successful adaptation of the AR-15 platform for piston operation. Long coveted by AR-15 collectors, these guns have been scarce and prohibitively expensive in the U.S. Now, folks who want to experience 416 performance first-hand have a truly affordable alternative, thanks to our new HK416-compatible BRN-4 Piston Upper Receiver Kit!

The kit contains all the parts needed to assemble a complete upper, including an original Heckler & Koch® HK416 stripped receiver and handguard. The rest of the HK416-compatible BRN-4 parts are new-manufactured for Brownells: bolt-carrier group with tough Nitride finish, gas piston, operating rod, gas block (and pins), barrel nut, and handguard retaining screw.

You can get your BRN-4 kit with a 14.5" or 16" barrel. Manufactured for Brownells by Faxon, the medium-contour, 5.56 NATO chambered BRN-4 barrel is slimmer than original HK416 barrels to keep weight down and help you build a well-balanced rifle.

Complete Kit:

BRN-4 Piston Upper Kit

All Parts Needed To Build A BRN-4 Upper.

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BRN-4 upper receiver kits come as unassembled parts. If you can assemble an AR-15 upper from parts, you've got the skills to put BRN-4 together. A muzzle device is not included, but the barrel's 1/2"-28 tpi threads mean any AR-15 flash suppressor or compensator is fair game. Good news: the BRN-4 upper also fits on a standard AR-15 lower receiver.
All NFA rules apply.