Originally Posted by
Jer
Polish pretty much every edge forward of where the case shoulder would be if you had the mag loaded up - mainly the two little side tabs and the front edge. Sandpaper works ok, a dremel with one of those non-metal abrasive grinders works faster. You don't need to round anything off - just de-burr the edges and make everything nice and smoove. People used to (and still do) complain about DPMS rifles jamming a lot, but it's the mags, not the rifles. I can't figure out why they don't polish out the mags at the factory - I'd think that would save them the bad rep. The failure to lock open is weird - never had that happen, and I load rounds singly (y'know - slow-fire style) all the time.