HI in this video I go extensively into the bolt failure I had on my AR15 chambered for 7.62x39. I discuss the steel differences between carpenter 158 and 9310 from the AR Performance Super bolt. A new manufacturer of a "high quality bolt" is Cason engineering shop.casoneng.com/index.php
this one is hard chromed. They also sell an enhanced firing pin, like Model One Sales, and also a hard chromed extractor.
MGI also makes a bolt as well but I have no experience with it or any other manufacturer than the ones I currently own.