I have a Ruger Blackhawk that I had drilled and tapped to mount a red dot sight to. I have mounted the base and scope twice and each time the base has worked loose after a couple of hundred mag loads. The second time I added finger nail polish to the threads. Do I need to add Loctite this time and if so which Loctite should I use?

I dont usually use any thing on the threads for scope mounting.... but if i had to i would use 242 blue loctite.

Ya, blue for me too.

Blue Loctite X3

I suggest cleaning all mating surfaces with alcohol. Loctite blue threadlocker on the screws. If this is not adequate to keep the mount tight try a few drops of Loctite 680 (green) on the mating surfaces of the mount / gun. If you do this you should tighten the screws quickly so the 680 can set thin.

I use blue Loctite on all screws with the heavy recoiling revolvers. A friend of mine suggested dental floss. One small u-shaped piece in the screw hole only. He swears it keeps the screws tight.

I have found that fingernail polish works very well.

I use blue loctite on all mounting hardware, regardless of caliber. Am I over doing it? Don't know, but I haven't had any move.

Blue loctite............

I don't think so. This is what I use as well.

I know no one will listen but Weldwood contact cement on the flat portion of the base in a couple tragic spots with blue loctite on the screw with a bead (small) around the inside of cleaned rings mounted on a clean scope will prevent heartaches. The rings if carefully tapped with a screw driver handle will come off and a slight amount of heat on the base will remove it.
But don't listen. Just keep trying everything else like I did and have fun doing it.
Has worked on everything big that I have.
Plus the glue can be removed with Cutex nail polish remover.

Blue