I have given up on getting upset about the yoke gaps on recent S&W's. As long as they are even-ish, like the one on my 640 below, I just ignore it. I thought someone mentioned above - maybe they deleted it - that the gap serves a practical purpose in that a grain of unburnt powder won't (or shouldn't) interfere with cylinder closing completely. I've never had that happen but I suppose it has some foundation in truth. I just carried my beater 637 again this morning - it has a gap very similar to the 640. The B-C alignment looks perfect, per my old guy's vision, even with the gap. I've been worried about encountering a coyote or worse during my pre-dawn walks and the 637 is great peace of mind!