Scope mount problem(spacer)!

[Kudu m77]

Hi there.

I fitted a scope on one of my rifles to see how it shoots. The rifle has detachable scope mounts and I could not get the rifle to shoot consistent groups. It shoots all over the paper. When I removed the existing scope from the rifle I noticed that there was a brass type of spacer on the inside of the rear mount. I guess this might have solved the problem for the previous owner of the rifle but it was not cut nicely nor was it cut to the right size. What can I use as a spacer on a scope mount? Would tin foil be an option?

Pieter

 

[rugerjunkie]

Your best bet might be a new base and rings instead of trying to fix the previous owners issue. Just a thought.

 

[Kudu m77]

The reason why I would like to keep the mounts is that I have been told by several experts in the field that the mounts are worth close to a thousand dollars, between 5 and 7 thousand South-African rand. At first I thought guys were just making it up, but the more I showed the rifle to gunsmiths and gun shop owners the more they told me that I am quite lucky that the rifle came with the mounts. Is the best way to fix the problem inserting spacers or should I get a gunsmith to look at the problem and maybe fix it in a different way?

Pieter

 

[Bitman]

Why is the spacer required in the first place?
For scope fit or elevation adjustment?

 

[JFB]

Why is the spacer required in the first place?
For scope fit or elevation adjustment?

I recall once getting a 24mm tube scope instead of a 1" as the box stated. it would have required 0.010" shims around the tube. However, the manufactor swapped it for me

 

[Kudu m77]

Why is the spacer required in the first place?
For scope fit or elevation adjustment?

It is for scope fit and not elevation. The spacer sat inside the rear ring. Sorry for stating my question wrong in the first place, I guess I should have said rings and not mounts.

Pieter

 

[norfolknova]

If I had to shim the ring to fit the scope I would use aluminum shim stock. This is material I use in my job for aligning pumps to motors. The kits I usually use start at .001 and go through .025 for the thinner material. The advantage to using shim stock over aluminum foil is you know exactly what the thickness is you are using and it is hardened. Here in the states you can buy a shim kit throgh companies like Grainger.com. I am sure some of the industrial supply companies over there would carry similar kits.

Matt

P.S. even though the metal is hardened it is still very cuttable and shapeable.

 

[Stonewall]

You can bed the rings to the scope with epoxy for a stress free fit.
Do a search on Benchrest.com. for more information .
Al really knows what he is doing .
http://benchrest.com/showthread.php?75120-Bedding-or-Lapping-Scope-Rings&highlight=bedding+rings

It would really help if you gave more information.
i.e. rifle , scope,and mount.

I presume this is a Mauser 03 from the cost of the mount ?

Glenn

 

[JFB]

If the problem was like mine, a 24mm scope tube with 1" rings, Can you swap to a 1" scope?

I have made "inserts" to put a 1" scope in 30mm rings, but that is a lot more than a shim

 

[Kudu m77]

You can bed the rings to the scope with epoxy for a stress free fit.
Do a search on Benchrest.com. for more information .
Al really knows what he is doing .
http://benchrest.com/showthread.php?75120-Bedding-or-Lapping-Scope-Rings&highlight=bedding+rings

It would really help if you gave more information.
i.e. rifle , scope,and mount.

I presume this is a Mauser 03 from the cost of the mount ?

Glenn

It is an older Walther rifle. I will try to find out what make the mounts are. The mounts have some very high quality engraving on them. Rifles and rifle parts tend to be a lot more expensive in South-Africa and I am sure the mounts might be slightly less expensive in the US. I spoke to a gunsmith on Thursday and he told me that some of these rings are 26mm and not 1''. The Germans made some rifle scopes with a tube diameter of 26mm. I got some copper shims today and it looks as if it might fix my problem. I will shoot the rifle and report back to you guys.(no other way to find out)

Thanks for the info.

Pieter

 

[JFB]

when using a shim to compensate for ring bore to scope tube mismatch, the shim should be just less than 100% around the tube/rings concentric for the first try. on the brightside, you can use that clearance to allow you to put the cross hairs in the center of their adjustment, then "step shim" to get on target. the inserts I made to put a 1" tube in 30mm rings are made off center for that purpose.

Have you measured the tube and the rings to see how much shim you need? If you have 26mm rings with a 1" scope, the shim to wrap will need to be 0.010" to 0.012". any material that doesn't compress will work, the other thing to worry about long term will be corission.

when measuring rings, you need to check accross the joint, since the joint is cut so that the halves clamp the tube

 

[norfolknova]

If you have a micrometer measurre the inside of the rings, then measure the sope at the mounting points. When you take your measurements measure side to side and top to bottom on both. This is to make sure that your scope and mounting rings are indeed still round. Subtract the scope diameter from the ring diameter and divide by 2. Add between .0005 and .001 to the total. This will give you the shim thickness you need to get a tight fit. Copper shim will compress so that is the reason for adding the extra shim thickness. Do not over lap the shim, make it as close to scope diameter as possible. Use a drop of locktite on the rscope ring screws to prevent them from loosening. If you tighten the scope rings with the shims in then loosen them you will need to put in new shims as the copper will compress. Good luck and take your time

Matt