We rescued several Armaliite uppers from DOE, the barrels were not apart of the uppers. ( They had pitting inside the rifling)
So for this build we used the following parts from that armalite upper rescue. All were from a complete upper minus the barrel.
Square forge marked receiver (came off of an armalite factory rifle).
NEW Colt 10.3″ 5.56 Barrel.
NEW Colt Delta ring assembly.
NEW Colt Gas tube & FSP.
New take off skinny carbine round 7 hold Hand Guard.
Armalite Birdcage muzzle device.
This upper is complete minus a charging handle.