I can't figure out the PM thing... Stupid computers! Here's the info though

What I've been having issues with is it jamming either into the face of the magazine well, or the shell will jam against the top edge of the chamber. I was thinking bad mags, and the guy at the shop mentioned that that could be a possible cause. But when it's clean, it'll run just fine. It's when there's been 50+ rounds run through it that it happens. And even then, it's about every third or fourth mag. For the bulk of my practice I use mccormick power 10s, I also have one eight round springfield that seems to work fine. But that's the one I usually keep in the gun when I'm carrying, so I don't practice but maybe sixteen rounds with that one. The pistol itself is a Olympic Arms 5" matchmaster. It has an 18lbs. spring, 2 1/2 lbs trigger, the action has been smoothed.