Brit plumber, the bolt is indeed marked as a 7.62. The receiver tracks have some uneven portions, as I suspect many rewelds do, but nothing binds as the piston extension ( bolt carrier) and striker move within the track smoothly and freely. I do believe the piston is a new, US compliant part. The gas cylinder is smooth under the bipod. Not sure if that means it is a type III or an original L4 cylinder? I have removed grease from inside receiver and gone to a light weapons oil.

Mr. E. Will look at mag to reinforcement stops but I have no knowledge of measuring those dimensions, so it will be a subjective observation. Mags lock in snug and there is little to no play in the mag release/ejector block.

Thank you all for the continued support and input.
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