Years ago while attending S&W Armours school in Springfield, Ma. we were advised to use clear fingernail polish. The front screw on the rear sight would work loose, so I started useing clear fingernail polish and worked great, when mounting a scope I use it on the base screws. You can break it loose without heat, yet I've never had it loosen up on me. I keep several bottles handy and if I have a loose screw problem I use it.