So the problem is that the group size varies between 0.5 and 0.7"? Isn't that pretty much a 0.6 MOA gun? I'm really confused as to what exactly it is that is upsetting you. You say even a consistent 0.7 you can live with, but it sounds to me like you are consistently shooting that and better. How can you not live with that? Are you getting larger groups, like 1.5 MOA?

It seems like you really know what you are talking about, but at the same time you are claiming to shoot between 0.5 and 0.7 MOA which is neither shabby nor especially inconsistent. That is a difference of +/- 0.1 MOA, so I have to agree that this sounds well within the range of shooter error.