First of all I appologize if I'm posting to the wrong forum, or this already has an active discussion elsewhere...I'm a newbie. So, here goes... I built an AR15 7.62 soviet and I'm having extraction/ejection problems. First of all the only thing that would happen was when I put a single round in the chamber it'd Fire and then come rattling back to sit in the upper with an open bolt. Casing looked a little frosty so I thought it might be a rough chamber. Ground the chamber with a little valve compound on a 12 guague barrel mop. This seemed to help and I got multiple ejected cases when testing. Then it began to stovepipe the casings, so I ground and polished the chamber a little more. I was very careful not to grind/polish more than a minute or so and the chamber looks real shiny now. Tested again and ejecting cases every now and again with also stove piping. BCG locks open with one round fired when magazine in place. If more than one round in mag it doesn't feed because the fired casing gets in the way or catches the neck on the front of the ejection port wedging the BCG open and crushing the case neck on one side. Casings don't have that frosty look any longer. I also checked the gas tube and block for alignment when I originally ground the chamber the first time. Lower is new from an 80% and so is the stock and buffer tube, spring etc. any suggestions much appreciated.