BRN-4A(R) BLEM UPPER RECEIVER ASSEMBLIES WITH NITRIDE BARRELS Look what we found! These blemished upper have machining marks left during the billet machining process that does not impact performance or function. Instead of discarding these, we decided to build these up into upper receivers and pass along a huge savings to our customers. Assembled from All New Components with Nitride Barrels, the BRN-4 BLEM Upper Receiver fits Standard AR-15 Lowers. The BRN-4A(R) BLEM Upper Receiver is now available as an Assembled Upper, with Barrel and Gas System installed. Simply add your preferred HKA(R) 416 compatible handguard and any 1/2-28 muzzle device, and you&rsq Mfg: Brownells