Manufacturer: JSE Surplus UK16DTIH9MGP
AR-15 Custom Piston Upper Receiver Assembly with One Piece Bolt Carrier Group, 16" HBAR Barrel and Adams Arms Gas Piston System
This complete upper uses a 16", 1:9" twist rate barrel and installs onto any AR-15 style lower without modification. The piston type gas system keeps hot gas, debris and powder residue from firing away from the rifle's bolt and carrier and improves reliability in harsh environments compared to direct impingement gas systems.
Heavy Barrel (ARR-630); M4 Barrel (ARR-631)