How to fix loose pistol sight dovetail

geologist

geologist

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I have an Astra Constable.

The rear fixed sight sits in a dovetail on the top of the slide. It came loose the first time I fire it. It is tapered and designed to enter the dovetail from the left side (safety/release side).

The sight base itself is tapered.

How do I tighten the fit in the dovetail. I have read that you can use a punch but would like some advice from you Nutz on how to do this.

Thanks for any help.

DSCN2627_zpszdikczjn.jpg
 
With a centre punch make some good dimples on the flat dovetail bottom. Degrease the sight and dovetail, drive the sight in, centre it and put a drop of red loctite into the gap under the sight. You can use krazy glue instead of loctite. Let it dry and go shooting.
 
Use the punch to flatten the bottom of the dovtail to stretch it out a bit, so it adds resistance in the guns cutout
 
Armafix is right to a point.

I don't like using center punches to make dimples. IMHO those dimples are fugly.

I have tightened up dozens of loose sights on rifles as well as handguns which utilize dovetails to retain their sights. I use a large chisel which has had its cutting edge ground off to a wide flat face. Make sure the piece is held securely if you intend to use impact force to alter the metal on your slide or barrel you don't want to slip. If done carefully the dovetail can be made to hold the sight tightly again under most conditions. Also the marks left behind will be non visible.

This can also be done in a vice or hydraulic press if again, care is used.

The peening with a center punch does work well and is the easiest fix. It is also a very easy way to make an ugly mess.

Whichever method you choose "CAREFUL" is the byword.

I should have added I do this only with the sight drifted out of the dovetail with a brass drift.
 
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You can also use a thin brass shim in the bottom of the dovetail. Try .003 or .005 brass available from hobby shops and the like. I have used that trick successfully several times and no beating on the gun required.
 
If metal is to be upset in order to tighten a dovetail fit, I prefer to work on the sight, rather than the barrel/slide/receiver.
 
bearhunter said:
IMHO adding shims will only exacerbate the existing problem even more.
Click to expand...

Not sure I follow but it's pretty easy to try and find out either way.
Peening the metal is a good technique but I agree with peening the sight before the slide unless the dovetail on the slide is deformed all ready.

JB weld or some other metal epoxy, a bit of file work and some loctite is yet a third option.

What size is the dovetail? Perhaps a new sight could be installed tight.

Lot's of options.

Geo if you do try a shim, it doesn't have to cover the entire bottom of the dovetail. Depending on how much tightening it needs a narrow shim may be all you need?
 
Thanks guys/ladies. I will try a brass shim first. I would prefer a method that will allow me to adjust windage to POA.

If I eventually have to peen I will. I am reluctant to peen the sight itself as getting another for an old Astra might be very difficult.

Hopefully the shim will work. I may try the beer can shim first just to try it out.
 
Buy a set of really cheap auto feeler guage. Then you have a variety of thicknesses (and sometimes brass with stainless feelers) for shims for a couple of dollars.
 
When I get home, I'll look through my box of PP/PPK parts for a proper rear sight. That one sure looks wide.

Peining the sight base is common practice, a drop of Loctite is even more popular. Anything that jams up the sight is choice 3 and for this, you can even use paper. I pulled apart an old revolver (antique) to properly clean it, a few months ago, and found the paper spacer under a cylinder spring had failed after 140 years. I fitted some new paper and the revolver cycles perfectly. Paper...

In the groove, it's not exactly exposed to the elements. A sliver of good paper is about your cheapest and easiest fix. Probably only good for 50 years or so, not the 100+ it used to last, but what can you do!
 
I went with the beer can shim and I'm pretty sure it's on for good now. It is on TIGHT!

I just painted it and bunch of my other sights with a base coat of white and then a coat of Neon Pink with metallic sparkles (my wife took me to Michaels).
 
The beer can shim is working well. It's shooting close to POA (6 o'clock hold on black circle) with Norinco ball at 7 yards. I shot this group two handed rapid fire.

The hammer is failing to lock back once every 3 mags. I assume this is a lube issue and will grease the rails with Ed's red instead running it with gun oil.

Astra%207%20yards_zpsvqdm4cb2.jpg
 
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