I put a question mark on that since this might just be a new gun needing better cleaning... Brand new Smith & Wesson M&P15 Sport II SKU: 10202 I am totally new to the AR-15. On sale at $499.99 I could not pass it up tho. It has only 141 rounds thru it so far in two shooting/testing sessions. The trouble is with rounds not fully feeding and getting damaged on the way to the chamber. This deforms the round as shown below and stops them feeding all the way into the chamber. At the worst it is every 5 rounds or so. I did a basic field strip, clean and lube before the first trip but it was a pretty quick cleaning and mostly just learning about the parts since the platform is new to me. After that I did more reading and did a bit more cleaning and tried to make it properly "wet" for the second trip out. At very first it was just as bad as before but this time I switched mags as soon as there was a misfire. I have two mags, one came with the gun and the seconds is the identical, so both are "PMAG30 AR/M4". The feeding trouble was the same for both mags. But then I continued to fire and the trouble seems to have gone away, in that I was able to finish up firing all rounds in both mags without any more issues. So it was as if that "wet" condition took about 12 rounds before the oil got everywhere. But maybe some pictures of the damage to the rounds will let somebody know exactly what is going on. I have 10 pictures hosted at: http://wombatz.com/hosted/2019-07-03 If you click on a thumbnail it will give you the full size image. Also adding one of the best pictures on this post. P.S. I will now do a much longer full cleaning in case the problem is due to packing grease or whatever you call it.