[bountyhunter]

The rear sight on my Ruger Mk II slabside keeps working loose and sliding sideways in the dovetail. This time I used blue loctite on it. Any trick to eliminating this problem?

[Vern Humphrey]

Drift the slide all the way out, and use a center punch to "dimple" the bottom of the dovetail, throwing up a bit of metal (it should look like tiny craters.)

Normally, when you drift the sight back in, it will stay in place after that. If you have more trouble, make sure the gun is properly zeroed, and use the center punch at the edge of the dovetail, against the center of sight base and make a small dimple extending into the sight base and the receiver metal.

[bountyhunter]

If it comes loose agin I'll beat on it.

[45R]

Thats funny that you had that problem. I've been reading alot about sights moving on the dovetail. It happened to mine not too long ago. Its good to know that if you cant keep it from moving the solution is beating on it. :)

[larryw]

Have you tightened the little set screw to the left of the elevation screw? That should keep the sight from moving in the receiver. If it still moves, remove the sight, degrease the dovetail and sight, apply a little locktite to the dovetail and reinstall. Tighten that setscrew down and you should be golden.

The dovetails for the adjustable sights on Mk IIs are a bit looser than the fixed sights to allow the shooter to mechanically zero the gun (thus the set screw) and use the windage adjustments while target shooting. Beating on them, while a good solution in other circumstances, isn't advised here.

[bountyhunter]

YES, the little set screw was actually tight. It's funny because I shoot it as an open gun (has a red dot sighter on it) so I wasn't using the rear sight (but the rear sight stays on). I just looked at it and noticed that the rear sight was moved about 1/4" to the right in the dovetail. The set screw was still tight and I couldn't push it back with my thumb. can't understand how it happened because it could not have gotten bumped because the red dot mount set up is wider than the rear sight. Very strange. I applied loctite and cranked the set screw down (again).

BTW: the effectiveness of the litle set screw is highly questionable. With the sight centered, look down the hole and you will see the screw is landing on the edge of the dovetail cut where it "breaks over" to the round part. I suspect this is why it doesn't hold properly.