Do the 7.62x39 AR15's have bolt head issues?

[Jeepster18_88]

I’ve built quite a few and my first ones both have well over 1k rounds each. Not necessarily high round counts but I haven’t had a failure of a bolt or extractor on any of them. It’s a stronger bolt design than the Grendel bolts so the assumption that it’s going to break bolts often doesn’t even make sense. The extractor breaking is more realistic but again, I haven’t experienced it yet. It’s also interesting to assume that it’s lower pressure when most AR 7.62x39 barrels have a groove diameter of .308 and they’re swaging down .310-.311 bullets so it’s quite possible for the pressure to be as high or higher than Grendel loads. It would be interesting to know how much that raises the pressure. In reality the cartridge should be able to handle the same pressure as the Grendel.