Originally Posted by
Dave J
I don't think the dovetail dimensions have anything to do with your problem. The usual complaints about M&P dovetails pertains to how tight or loose they are, and the corresponding amount of sight fitting that is sometimes necessary. Taking a few thou off the bottom of the sight to get it to fit the dovetail isn't going to produce anywhere near the deviation you're observing.
Maybe I missed it, but where does the gun actually print with your carry ammo, using either of the sight pictures you drew above?