There is no one-size-fits-all answer to this question, as the tightness of your pistol grip will depend on the make and model of your gun, as well as your personal preferences. However, there are a few general guidelines that you can follow when tightening your pistol grip.
First, make sure that the screws that attach the grip to the gun are tightened evenly. If one screw is tighter than the other, it can throw off the Balance of the gun and cause targeting problems. Second, don’t overtighten the screws – they should be snug, but not so tight that they strip the threads or damage the grip itself.
Finally, if you’re unsure about how tight to make your gun grip, consult the owner’s manual for your specific gun model.