Shimming scope rings?

[lowndsie]

While bore sighting my 22-250 the other day, I've noticed that I cant adjust the scope any futher and it seems the front ring will need to be lifted somehow. Just wondering how the best way to do this would be and also what sort of material would you use as a shim?? Is this a common thing as I've never had to do it with any of my rifles before?

[Ned Kelly]

G'Day Lowndsie,
You may need to lap the scope rings to suit but try swapping the rings front to back and to see if that makes a difference.

Alternatively, try cutting up an aluminium coke can to use as shims or go to an engineering supply store to get stainless steel shim material and place that under the bases. To gauge the thickness required, place a steel ruler across the 2 bases and uses a set of feeler gauges to measure the gap between the ruler and the lower base. Make the shims to suit this dimension.

I hope this is some help.........
Cheerio Ned

[wb243]

Lowndsie

I don't know a lot about scope rings, but I have heard of 'long range' rings which are used for long range shooting. Some scopes don't have enough vertical adjustment in them, so the rings do some of the work first by putting the front of the scope nearer the barrel. This allows the barrel to have more elevation BEFORE scope adjustment is used.

Hope that makes sense?!

[Kenny]

Lowndsie,

Presuming you have two piece rings -I would be carefull shimming up just one ring as it could put pressure on the scope tube from the misalignment. I have never experienced your problem, perhaps sighting it in will make things better.

If you have a bridge mount or one piece base it would be no problem and most gunshops have 'shims ready made of varying thickness to suit the screw holes in most guns I too have used neds method of aluminium can under the base and it works well
I just convinced myself recently that the alloy may be too soft to maintain a constant tension.....though I used some under the pillar of a mates mount to firm it up

KY

[Tasco]

Mate real easy get a set of Leupold long range mounts from Sinclairs. They give you an extra 20 thou, my 22-250 I now have scope adjustment out to 900 meters.

[shane]

Sometimes mass produced rifles and scope mounts dont line up. ie. the mounts are not parrallel to the bore line for short range use.

To fix this properly you mast change the base set up or alter the existing base and ring set then lap once done.


The poor alternative is to shim.
If you shim a set of rings you will apply stress to the scope and action when you tighten down the ring screws.

If you must shim then use a softer material such as a business card for the higher end and a piece of A4 paper for the lower end. This gives slight compression and helps reduce scope stress and can prevent denting the scope tube.

Once you have the correct amount of packing apply some release agent to the scope and then impregnate the packers with locktite and assemble into place this will harden giving a very solid and formed base for the scope to lay on.

The alternative is with two piece bases you can put the packer under one of the bases between it and the action then relap the rings after to give perfect contact and no stress.
The same with a one piece base but it must also be bedded onto the action so no stress is applied to the action or the mount.

If the gun shoots to high pack the front and pack the back if its to low.
cheers,
Shane