RobertJ,

Over tightening is bad - but so is under tightening. If screws are left too loose, grips move around under recoil and can be damaged then also. Proper tightening is of the upmost importance with all screws wether on guns or anything else. It's very hard to convey what is proper on a computer .......

Tight enough to keep parts from moving but not tight enough to deform them, bend them or crush them. That said, the little rubber O-Rings will allow a larger window of error I suppose.