Ok, here's an update. We just got back from his gunsmith, who also did the reloading. First of all, the fellow has been reloading professionaly for over 20 years, and has never had a problem with a single round. Upon examining the spent rounds, half of them showed a slight ring @ 1/2 inch up from the base of the case. After this, it was determined that the left barrel (the one that had the case seperate) showed borderline excessive head space. From watching my friend shoot, I also believe that he may have had the side of his thumb in contact with the action lever, and upon recoil, the rearward movement caused the lever to come into firmer contact with his thumb causing the action to open. My friend was also wearing a shooting glove at the time, and may not have felt the thumb in contact with the lever. Does this make any sense to you guys?