Ran about 300 rounds through the M40 yesterday and at approximately rnd 250 or so I had a failure to feed. I was using WWB 180gr fmj ammo. It was easy to clear and I fired the rest of my ammo without incident. What I noticed when clearing the round was that the feed ramp was incredibly dirty. Not just black but caked. 8O I have not had any problems with WWB being dirty in the past but man it sure is dirty now.