I went to the range today for the first time with my AR15. It's of LMT make, with the enhanced F/A enhanced bolt carrier assembly. I only fired 80 rounds through it. Got home, took it apart to clean the rifle. I took apart the bolt carrier assembly cleaned it, and tried to put the bolt back in the carrier. (note - this rifle is familiar to me, I am in the army). It wouldn't go back in, there was some resistance, and I just coulnd't get it back in. So I looked to see what the problem was. Two of the bolt rings were not in place, they came loose. One was worse than the other. I have never had this problem before with a C7. Before I took it to the range today I had taken it apart a few times, and I noticed it was stiff putting putting the bolt in the carrier. I figured that was because its a new rifle. I tried putting the rings back in place but failed to do so. I think the two rings may be streched. I'm not sure how this happened. Has anyone had this problem before? Should I take it to a gun smith? Replace the rings, and if so where should I buy them? Thanks.