Got Novak sights on a Springfield loaded.  Had a problem with the original screw getting stripped.  Springfield sent me a replacement.  Problem is, I cant keep the rear sight from coming lose.  

The rear sight slides in and out pretty easily when you loosen the screw.  What (if anything) can I put on it to keep it from coming loose?  Red Loctite?  I  tried some Blue loctite on the screw and it didn't cut it.  Seems like someone told me (or I read it) to coat the dovetail cut and screw with red loctite.  Is that enough to hold it?

That'll do it.
Later, if you ever need to remove it, just apply MILD heat of about 300 degrees to break the Loctite down.

Best installation here is to use a good solvent like lacquer thinner to degrease the slide dovetail and the bottom of the sight.

Dry, then apply the Loctite Red.  This will insure a good bond.

Great.  Thanks for the info.