A good smith that is familiar with ARs can tune the ejector. There are many posts on other forums about taking the sharp edges off here and there so they are not so hard on the brass. I myself would not do it, I would have to take it to someone. The only other thing I could come up with is a gassing problem, sounds like it might be over gassed. But I sure do not know enough about it. I do know that Spikes 308 lower will not work with some DPMS parts in a 308 setting, a friend and I just found that out. But Spikes fixed the problem for the friend and sent him their parts. There does not seem to be a written book about this yet and some of the parts from some gun places seem to be different, they are making what they think is right. The only thing that was told to us is make sure you start out with the same upper and lower, good quality parts and get the barrel and bolt/extractor from the same place, after that it seems like they are good to go. Good luck. BANG BANG!!