I'm looking for a little advice a out my DPMS. It has been very inconsistent in the accuracy department. I bought this upper to shoot in local tactical matches that get out to the longer ranges. So far, the inconsistent grouping has hurt me in matches, and cost me a lot of money in ammo trying to get it figured out. I think the issue may be heat related, but I'm not positive. I'm shooting at pasters at 100 for load dev. It will shoot about 4 groups of 5 shots, that are usually under an inch, in the .6 to .9 range, which is ok, then it starts having super crazy odd ball fliers that open groups up to 2 plus inches. Once in a while it will go over three inches. I don't shoot it fast, I mark each shot for my records, and take my time loading the next five so it doesn't get too hot. Sometimes I take another rifle and shoot 2 groups from the CM, and 2 groups from my 308 to keep it from getting too hot. I'm shooting 3" from the CM and .3 from the 308. Sometimes it literally starts shooting back and forth, every other shot, left right left right. I will end up with two groups two inches apart. It did this Saturday and the 3 shot group was .11, and the 2 shot group was .08". I can't flinch good enough to do this on purpose! I have tried 120s and 140s, and have some winchester with 142 smk to try this weekend. I have pulled the scope off and shot it on another rifle with good results so I don't think it's my scope. (Bushnell elite tac 6x24 with a G2 ret in a Larue mt). I have shot it clean and dirty with the same results. I called DPMS today and talked to their rep, and I may as well been talking to someone at bed bath and beyond. Guy had no clue, could give me no ideas why it would do this. He did say that I could pull it down and re torque the barrel nut and it will not void the warranty. After that I could send it back, but they are out of barrels and it would literally be months before they get more in. I have put over 350 rounds through it,trying to figure it out and it is driving me crazy! Has anyone out there had this happen with their big gas guns before or am I just going nuts? I could really use some advice.