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I discovered that the rear sight on my MK II Target model had come loose and was sliding back and forth in the dovetail. I tried tightening the hold down screw but I couldn't get it to turn more than a few degrees clockwise and only back to its original position counterclock wise. I removed the sight from the gun and placed it in a vise. Thinking it might have had some loctite applied to it at some point in its life, I heated it carefully with a propane torch. Still a no go. I thought about degreasing the sight and the dovetail and applying some blue loctite under the sight and letting it dry, however that seems like a half-fast way of fixing my problem. So, I decided to come on here and ask if anyone has a suggestion for either removing that little screw or at least a suggestion on tightening the sight in its dovetail.

It sounds like there is either some dried-up Loctite residue in the threads, or maybe the threads have been deformed somehow.

I would start by soaking the threads and screw with "Liquid Wrench", "Knock Er Loose", or "Kroil" if you have it. - Some kind of penetrating lubricant for stubborn fasteners.

Soak it overnight, then see if it behaves any better in the morning.

If this does no good, I'd look it over carefully with your best magnifier, inspecting for physical damage. Removing stuck screws can be a pain.

I'd look for videos on YouTube about removing stuck screws and see if any of the methods there look right for your situation.

thanks for the suggestions. I have the sight soaking in a bit of WD-40 for the night.

In the past on some of the habitual sights that want to move, I have removed the sight base and stippled a few large dimples in the bottom of the dovetail slot to increase friction and improve the holding surface.

R,
Bullseye

Depending on which loctite was used it may need to get near 450F to have it let loose. Use a soldering iron on the screw till you see smoke. Once you see the smoke it hot enough to break the loctite down.

As far as tightening the sight to the dovetail slot. Do what BE suggested, if a super loose you could use a shim.

If the set screw will not move I would work on it till you can run it in and out. Then you should beable to tighten it.

Thanks for the advice from all. Here is what has transpired. I tried heating the area once again and managed to get the screw to wiggle a little more, back and forth. I then left it soaking in WD-40 over night.

Dried it off this more and began working it out, by the wiggle it back and forth method. Once the slotted portion of the screw exited the threads, one side promptly broke off. I managed to get a small pair of needle nose pliers to grip the side that was still attached to the screw and after about another half turn, it too broke off.

I turned the sight upside down and decided to drill a small hole into the screw with the hopes of using the hole to lodge a small tool in it, perhaps with bit of epoxy for good measure. So far all I have been able to do is polish a small dot in the center of that screw.

Ruger has a rear sight for 28 bucks that I assume would work, but I can't give up on this thing that easily. It's the principal of the thing (I could take the one of my wife's Ruger, but she might notice it missing). Anyway, we are experiencing a thunder storm at the moment but as soon as it passes over, I'm heading back to the shop for round 8, Battle of the Set Screw. You may see this turn into a Reality TV show before it's over.

Sorry to hear your still having problems. So this was a slotted head set screw. Wonder if it's been replace since mine are allen head. I'm not sure you have got it hot enough to break the Loctite down. Normally once you break it down the come out very easy. You have to keep heat on them till they start smoking.

Blue,

I just looked at my wife's MK III ss target and it has a slotted screw as well. I finally gave up on trying to remove the set screw and drilled a hole on the opposite side of the sight. I'm going to tap it for another set screw as soon as I determine what thread the original hole was tapped.

THX for the help

Well, it's done. I drilled and tapped the opposite side of the sight 6-32 and installed it back on the Ruger with a hex socket set screw. Not pretty, but functional.