Loose RED dot mount - Walther GSP

Hi, 

I have a Champion scope mount on my .32 S&W GSP.  I have been seeing inconsistent scores and during tonight's competition I discovered that the whole mount was loose.  What seems to have happened is that the recoil has enlarged the 3 mm holes in the side of the mount.

I am sure that once a small amount of movement started then the recoil continued to do the rest.  I could repair it but I think the design is flawed. It really needs tapered pins.

Has anyone else seen this problem?

Thanks, Paul

Tapered pins might not solve the problem.  The problem is usually large holes for the screws.  The mount is only held on by the clamping action.  Bush the holes with an interference fit bushing and drill them to a size that just fits the screws. It is also much better with #8-40 screws.

The current design has 2 x 3mm parallel pin that pass through existing sight mount on the slide.  The idea of creating a clamping action with some screws is an interesting one.

My initial thought was to TIG weld the holes (assuming the alloy can be welded) in the existing mount and ream them out to 3mm but unless it is a really tight interference fit then the problem will re-appear.  Thanks for your thoughts.

As an aside I have a similar mount on the .22 slide made by Earls.  So far so good, but there is a lot less recoil.

I don't think TIGing the holes is a good idea. Amount of heat to TIG aluminum will remove any treatment there may be if any. If it's any of the 2024 or 7075 aluminum type alloys, they are not weldable and the attempt may ruin your mount. (I did read someplace that those alloys do have a welding method developed but not knowing the alloy can be disastrous) I like Wobbley's bushing method better. I'd use stainless steel to make the bushings.
  Aluminum will creep at a much lower pressure than steel, sandwich clamping with aluminum is not good. Use the size of screws or pins to limit movement, scopes and mounts will want to move forward with recoil so when installing push everything forward when tightening.

I have the mount I purchase from Earl's, it mounts with 2 horizontal pins, and is then secured with 2 vertical set screws.  I had issues with the 2 pins coming loose, Earl told me to insert them left to right (mine were R to La).  He said the recoil torque of shooting would tend to cause the pins to move to the R.  I changed it, and have no issue since.  Might be worth calling him.

I also have the Earl's mount. One of the horizontal pins used to try to walk out a small amount after many rounds. Pulled the pin part way out, applied a drop of blue Loctite. Pin hasn't moved again in 2 or 3 years.