Rear sight loose on my Mark II

[Roger Williams]

I just recently bought a Ruger Mark II (fixed sights). On the first trip to the range with it, the rear sight slowly slid to the right after about 120 rounds. I only noticed because my groups were still tight, but slowly moving over on the target. I tapped it back into place and it shot fine for a while then started to move again. This time when it worked loose I tried to move it with my thumb and it slides just barely back & forth and makes kind of a "clicking" sound.

What should I do with it? I just want to get it back on target and make the sight stop moving. The model I have is the MK-6. It has the 6 inch tapered barrel and fixed sights.

Other than the rear sight, I really like the pistol! It has a VERY nice trigger, and only jammed once going through a whole brick of cheap, crappy .22 ammo. This problem is really strange to me because my father has a Ruger pre-mark standard and his rear sight has been rock solid for darned near half a century!

 

[cornbread2]

Remove the rear sight and LIGHTLY peen the top of the dovetail.

It will now go back into the slide tightly.

 

[Roger Williams]

Do you mean peen the sight, or the notch cut into the receiver?

Would locktite work? I'm worried about screwing up the gun. I'm not even an amateur gunsmith!

 

[cornbread2]

Peen the top of the middle of the dovetail in the reciever. Just lightly.

Locktite may work but peening is the corrrect fix.

 

[E=MC^2]

I just recently bought a Ruger Mark II

But peening the receiver of a new firearm is not.

A common fix in most gunsmithing manuals is simply turning the sight upside down and making a strike with a center punch. This creates a 'dimple', or 'crater', and raises the metal around it. This creates enough friction to hold the sight in place. It becomes unbelievingly tight. I've did it on USED 1911's that had dovetails cut too large. Had it been a NEW firearm I would have let the dealer take care of it.

 

[E=MC^2]

The military armorer's method for securing a loose rear sight is to smack the center of the slide dovetail with a center punch. The raised metal around the punch mark should be enough to keep the sight where it belongs. A less elegant alternative is to hit the top of the dovetail across the "ears" with a hammer to close the dovetail. Me, I much prefer method #1!

It did not steel my info from DSK. I just came across this post in a different thread after I wrote mine. Although they differ slightly, the same principle applies. The center-punch method is very effective.

 

[yzguy]

then there is also the set screw that can be tightened (and use loc-tite)....

 

[Roger Williams]

My gun is the "fixed" sight model. (so it has no screw - I kinda wish it did)

Well, it's supposed to be... it's just a little more "movable" than I'd like.

 

[yzguy]

oooohhhh....

 

[Roger Williams]

just wanted to post an update to this...

I was able to fix the loose sight yesterday. I tried to make a dent with the punch on the bottom of the sight first, but the metal the sight is made from was MUCH too hard... so I made a ding right in the middle of the dovetail with the punch - it was still loose. So I took it back out and made 4 more dings in the dovetail with the punch. (an X pattern with 1 in the middle) After that, it was pretty hard to get back in, but at least I know that sucker's not going anywhere now! Can't wait to get back out to the range and plink some more with it.

Thanks for the help fellas!

 

[bountyhunter]

I think this is why God made red Loctite.

 

[Roger Williams]

I didn't want to use red Loctite because I won't know if the sight is "zeroed" until I shoot it again. If I needed to adjust it at the range, it could get real inconvenient after using the red one... (it might involve torches, big hammers, etc.)

I could have taken it to the range, made sure the sight was in the right place and Loctited it there, but then I'd have to wait for it to dry before I shot it again.