Have a DPMS .308lr with 10rnd mags. From a fully loaded mag I can get 3rnds off and then it won't fire the next. A look at the mag looks like the top round is pushed down just enough so that the bolt won't catch it. Is there a simple solution to this, other than just buying better mags? I feel like I've read somewhere that DPMS mags are fraught with this very issue.