The Armalite AR-10®A4 A-Series flat-top upper receiver is made from forged 7075-T6 aluminum, features a flat-top with MIL-STD 1913 rail and a thread size of 1-7/16″x18″ UNEF-3A. AR-10®A4 complete upper is Armalite's 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.

*Compatible with Armalite AR-10® A-Series lowers.