I too have a 22/45. i have had no such problems with mine. other than not to feed it federal ammo. It sounds to me that there is too much tolerance where the screws fits. i would first take a closer look at the relationship between the screw size and the tap diameter! although, that it be tough to do if you have locite now filling your thread voids.
option #1 call you local harware store and explain to them that you are in need of some new metric screws for your gunsight. ask them if it would be ok to check the tap size or try a couple different screw sizes, to be sure they work!!(DO NOT GO IN THE STORE UNANNOUNCED AND SUPRISE THEM WITH A GUN)
option #2 go to your local hardware store and ask them for a roll of teflon tape. Appx 2.00 for 25' roll. cut a small piece off diligently and wrap it around the screws the same direction they will tightened.