Ditch the Thunderheads. Too large, causing the bolt to plane. Cost me two bucks to find that out. Get a smaller head, preferably 4 bladed (Slick Tricks) less tendency to steer bolt. I've experienced some of the same issues. Went to Gold Ring Lazer II's with 110 gr brass insert, 2" Blazer vanes and 100 gr Slick Trick mags. AWESOME!!