I've got a ruger mark 2 with an adjustable rear sight. The problem is that the horizontal pin at the front of my rear sight on my mk2 keeps working it's way out when I shoot and I have to push it back in. any ideas on how to keep that sucker in there? I am hesitant to use loctite on it for fear it might prevent the elevation adjustment from working right. (don't know if the information is helpful or not, but the pin comes out on the left hand side and I shoot left handed)