Loctite makes a RANGE of products, within each broad color, and you don't want to use a "nuclear grade threadlocker" when what you want is something to keep gun screws tight.
I recommend a product called "Guntite" though I haven't gotten any in ages (still haven't used up the small tube I got years ago) not sure if they still make it. Stuff I got was in a white tube with green lettering. Is it "green" loctite? I don't know, don't care. IT works great!
DEGREASE (remove all oils/grease) from the threads and screws don't back out or loosen, but can still be removed easily with the proper screwdriver or wrench. One SMALL drop in the threads is all you need.
One other thing I would recommend, taking the needed tools for all your gun screws to the range with you, and using them when needed. Will probably save you some ammo.
What I do, when a gun isn't shooting well, first thing, is check ALL the screws, WHILE AT THE RANGE. Tighten what (if anything) is loose and shoot some more to see if that solves the problem.
If so, you can "loctite & torque" the screws at home afterwards.