At the indoor gun range this morning I fired 10rds from my Aero PRecision AR15 and after the last shot the BCG locked back but the bolt did not retract. This prevents me loading a full magazine. This is a new development on the new AR15 which has only been shot a total of 70rds. I used same ammo PMC 223A as before when there were no problems. I have been lubing both my AR15's with Mobil 1. The PSA AR15 has a PSA BCG and runs perfectly with this lube. The Aero Precision, with an expensive Tool Craft Nickle boron bolt and BCG, is the one giving me the problem. Perhaps I did not give the BCG enough lube. I need a little advise have from the cognoscente.