I have a mesa in a 7mm RM. During break in, it was between 1/2 to 3/4min very consistently with 162gr ELDX ammo. Groups began to open up on the next couple shooting sessions and I had found one of my scope base screws had loosened up on me, Retorqued base and scope to spec with loctite and all has been dandy. That being said and as others have mentioned, its puzzling that it would shoot sub moa and then go back to shooting like crap. Have checked your free float to make sure that the barrel is not making contact? Christiensen has been known to use excessive compound on their "spot beds". Ill be eager to hear your results after you get your gun back.