So I picked up an AR at a gun show, It was built with mostly good parts, Noveske lower and "keyhole" upper... the only questionable bit is a unstamped barrel... (I know there are some reasonable barrels that are not stamped but i just dont like the fact its not)..... I took it out this weekend and the gun wont cycle. The bolt does not move at all.. I was using steel case ammo ( all I took out with me unfortunately ) but its not a feed/jam situation. It could be fired and the spent case ejected and a fresh round loaded with a tug on the charging handle.... The only thing that I can think of is the gas port on the barrel is not timed to the gas block... I have never had a barrel out of a AR and I dont really know how they mate there but I just cant imagine that if gas was present even a little in the action that the bolt would at least jump or wiggle or something... but far as I could tell it was locked shut.... bolt and carrier are properly assembled and move freely in the upper.. plenty of lube.... Anything I am overlooking?