I haven't resorted to going up to the garage to get a torque wrench and hex bit to put my gun back together.
I did try blue Loctite. It didn't work. The screw is such a precise fit into the hole that the Loctite was pushed out onto the mating surfaces of the receiver and frame, where I found it the next time I cleaned the gun. The internal and external threads had no Loctite on them whatsoever.
I've just been tightening it very tight, tighter than I would like, and have not had the problem again. The only thing I worry about is wearing out the internal flats of the hex interface.
NRA Benefactor Member