Gun Doc,
Have seen the same over-tightening problem numerous times not just with Weavers but other mounts--of course due to many people wanting to "make sure" everything stays put, and over-tightening the screws. (Robert Pirsig wrote at length about this in ZEN AND THE ART OF MOTORCYCLE MAINTENANCE.)
Have also seen the two screws on the top half of the mounts over-tightened to the point the threads in the bottom half of the mount (the saddle) are stripped out. Which of course causes other problems, not always diagnosed correctly by the average shooter.
