Armalite AR-10 A4 B-Series Upper Receiver Assembly

Complete upper receivers include: AR-10 port door assembly (EA1165), AR-10(T) port door rod (EA1171), AR-10 / M-15 port door spring (EA1167), and AR-10 forward assist kit (10005001KIT). AR-10-A4 complete upper is our standard flat top upper with the standard port door rod used for all AR-10’s that will utilize a 2-piece handguard. If a free float handguard is to be used, the 10002000 AR-10(T)TM complete upper is needed. Forged flattop with mil-std 1913 rail and laser engraved rail numbering.