New to the forum

, been lurking a while though.
I don't know about buying a complete upper, but I just built my second x39 upper with YHM and DPMS parts. YHM still sells chrome lined 16" barrels and I used their parts for everything but the receiver, they had none and had no idea when they'd get em. I used a DPMS slick side receiver and a MGI bolt and firing pin to finish out. Had to do some dremeling on the feed ramps to match the barrel and receiver together, did a function run and she runs flawlessly. BTW Midway has the MGI bolt/firing pin on clearance for $79.