daizee - I'm a bit overweight. My cheeks shift a little. I break my weld and not only do I have to get it in the exact same position, I have to move my fat around and back into the same position. Your weld may feel the same, but it very well could be 1mm off, and that is a different viewing angle on the rear sight. Like I've said, I only see it really mentioned in competitions, and mostly 100y, slow fire, prone, rimfire matches. These are the same guys that are shooting accurized and customized Win 52D's or anschutzs to be competitive. I haven't been around bench rest comps. That's also where you generally see the smallest groups (besides bench comps), and you have to be dang near perfect to win. Shooting off hand, I would reckon, that groups are a little (not saying much, but a little) larger and therefore the 1mm offset isn't as big of a deal. Do they do offhand competitions at 100y with rifles?