Well finally after three months of searching and waiting, I have my new upper receiver. I had originally ordered one from Model 1 Sales back in October. I wanted a 24" stainless bull barrel with flat-top receiver. When I received it, it refused to feed ammo from my mags ( Sanchez, Center Industries, Colt, AND Bushmaster mags!!!!) I sent it back and they polished the feed ramps and told me that it worked flawlessly. When I got it back it was a little better, but still wouldn't feed from the left ramp, so I returned it for good. I ordered another one from Gunsmoke Inc. on November 8 and just got it from UPS ten minutes ago. I cycled a full Sanchez mag through it without a hiccup! Thanks Gunsmoke for making my Xmas wishes come true! The fit and finish  are perfect. I can't wait to mount a scope and see what this thing can do.