1. Sight rail screws keep loosening. Sometimes, the barrel screw backs out, too. Locktite will keep the screws from backing out but I think it caused the screw head of the rear screw to break off on one of the my pistols.
My barrel screw had factory thread locker on the threads but still backed out.A little red locktite helped it stay tight.
My sight screw backed out one time.Figured out the problem.I left out part #58 in the diagram on the rear screw.No problem since.