I’m assuming that the BCG is an integral part of what makes a“quality” AR, obviously along with the barrel and trigger. I knew a guy that had a business that assembled about 250,000 BCG ‘s a year. At that time there was much chatter about nitride, shot peened, magnafluxed..........whatever. He supplied to many of the big name guys, including some of the very high dollar guys.
So anyway, I asked what the difference in the quality was. As far as BCG’s he said all his were identical
The problem with these stories/claims is a number of the top tier manufactures have proprietary systems. Sorry that PSA sourced bolt will not work in a SR-15. etc. etc.