First of all I am pretty sure my issues are solved. I purchased a brand new MKIII target. I had not even bothered shooting the gun, before I ripped it's guts out. Installing a Volquartsen trigger kit really does make a major improvement. Shooting the gun, I experienced three stove pipes in the first 50 rounds. The failure to extract I attributed to the gun being new, and not broken in. Still, I couldn't take the chance of a stove pipe during a match. I went ahead and ordered a Volquartsen bolt kit. After getting it installed, I took it out back to test fire it. Shooting the same magazine I had been using for the last 400 rounds, and the same ammo Winchester Super X. I experienced one stove pipe right after another. Doubting the new parts caused this, I broke out my extra magazines. Two would cause serious stove pipes, and two were reliable. I was aware of the magazine fix though. I took one magazine, and polished up the feed lips with a Norton triangular india stone. I only had time to run 15 rounds through the magazine, but it seemed to solve the problem. I hope to experiment with it more next week. The number one cause of stove pipes in the MKIII, is the crappy stamped extractor. A fix of course is replacing it with a better part. While I am not sure what was going on with the magazine, polishing the feed lips helped. I did not file them off to the extreme as some, but only enough so the round doesn't slow down coming out of the magazine.