Designed in conjunction with PWS & FM Products, the Brownells BRN-180S® Complete Upper Receiver is the newest iteration of the BRN-180® Upper Receiver, which was inspired by the Armalite® AR-180 of the 1960s. The BRN-180S® shares a large chunk of components with the BRN-180® but introduces key features to improve reliability and usability in a short configuration.

With an entirely self contained recoil system, the BRN-180® can be mounted to lower receivers without a buffer tube. This allows for easy compatibility with folding stocks and rear picatinny adapters. Recoil guide rods and buffer easily remove from the rear when removing the upper receiver from the lower. Bolt and carrier easily slide out when removing the charging handle at the rear. Large ejection port allows for ease of access for cleaning.

Lightweight barrel profile sits inside the slim handguard, making for an extremely lightweight package, even with the piston driven system. Top picatinny rail sits extremely low compared to other piston systems, allowing for broad compatibility with common AR-15 height optic mounts and sights. Barrels feature a 223 Wylde chamber to function with the broadest spectrum of 223 Remington and 5.56x45mm NATO ammunition.

Free float MLOK handguard is free floated, and can easily be removed with one large screw located on the bottom of the receiver. This screw engages the rear of the barrel, pulling the handguard tight up against the receiver. Easily removed handguard allows for quick access to the BRN-180® gas system.

Gas plug has two settings:
U = Unsuppressed
S = Suppressed

• Ultra-reliable AR-180 piston operating system Compatible with current mil-spec AR-15 lowers
• Machined 7075 T6 aluminum receiver & handguard - hardcoat anodized finish
• 10.5" Nitride Barrel
• .223 Wylde chamber
• Button rifled bore
• 1-8" twist for both the 223 Wylde
• ½"-28 threaded muzzle for 223 Wylde
• A2 Flash Hider
• Molded polymer ejection port cover
• All NFA rules apply

All BRN-180 Upper Receiver Assemblies are test fired before final packaging. Upper may display signs of firing, such as or slight fouling inside.