Recommend a smith to finish my upper.

[noone]

For what it is worth, I agree with the previous suggestions that the issue is in the Gas system. On my gas systems, I insure that the gas port in the barrel, and the gas tube isn't obstructed. To insure that all the gas from the barrel enters into the gas block, I have the port enlarged so it is like a cone shape rather than just a hole. That way if there is a wee bit of mis-alignment, all the gas enters the system.

I had similar problems to what you describe. New gas rings solved all the problems. Apparently there was one bent, or out of spec ring.