I originally posted this under the "Chambering Rounds from the Magazine in the FS2000" thread but never got any responses so I thought I'd post it as its own thread in hopes of getting some thoughts from those with more experience. ---- I have inserted fully loaded magazines on both an open and closed bolt with no problems but I did have one interesting thing happen: Load magazine. Charge. Shoulder. Select to "1". Aim. Squeeze. BANG. BANG. BANG. BANG. BANG. Click! Huh? Go safe. Open inspection port. Looks OK. Lock charging handle back. No round chambered. Look in at magazine. That looks odd. Round partially stripped. Remove magazine. Round is partially stripped. Lip of left side cartridge caught on the forward metal of the magazine. Bolt must have jumped over the cartridge when it jammed and finished closing. Bullet is jammed half way into the throat of the cartridge. Popped the nose of the cartridge up and stripped it out by hand. Inspected the magazine and noticed that the metal halves were not quite lined up. The left half was lapped up about .040 over the right half, just enough to catch the cartridge. Took my grinder and evened them up. No further problems with that magazine. Using XM855 with a stainless steel C-Products (original, not Defense) magazine. A week or so later, happened again. One left hand side round jammed with the bullet pushed half way into the throat of the casing. 1 round out of 120 (4 different magazines I shot that day). 55 grain XM193 in a C Products Defense aluminum magazine. No obvious lap on the front of the two halves. The cartridge was more than half way out of the magazine when I pulled the magazine. Seems like this one just failed to climb the ramp. It was about 6 or 8 shots into the magazine. Looking at other AR15 style magazines I note that many have much deeper relief in the front than the C Products magazines. Probably would have prevented the first instance but not the second. Anyone else experiencing these left side half feeds? Thanks for any insight.