BRN-180 Upper Receiver Group Gen2 Reliable Piston System Made Even More Versatile Designed in conjunction with PWS & FM Products, the Brownells BRN-180 Complete Upper Receiver is inspired by the Armalite AR-180 of the 1960s. Developed as a successor to the original AR-15, the AR-180 was a civilianized version of the AR-18, itself an upgrade on the M16 platform. The BRN-180 incorporates many of the AR-18/AR-180 improvements – including its robust and reliable gas piston operating system. (Yes, the originators of the AR-15 / M16 eventually embraced a piston!) The BRN-180 Gen2 Upper Receiver Group improves upon the original BRN-180 with two main Mfg: Brownells
