With regards to the round hanging on the upper, are you riding the charging handle or letting it slam home from full compression?
I I have a trick I do to all my barrels prior to install. I take a small diamond dust file and bevel the corners on the 5 and 7 o'clock cut-outs in the locking recess(barrel extension) and I polish the feed ramps below and this area too with a felt bob on a dremel and jewler's rouge. I assure this area is a smooth as a babie's bottom.
Also, check your recoil spring assembly.
My brother saw Deliverance and bought a Bow. I saw Deliverance and bought an AR-15.
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