Shimming

S

Scribe

New member
Hi chaps, I would be interested in any suggestions about the following problem.
I have a Yugoslavian K.98 in 7.92 and have fitted an S&K scope mount to it. The mount is excellent and I have used it for years with an old Burris 2.75 Scout scope. This has just been been for fun, plinking on the range out to 200 yards. The problem has only appeared since I decided to get clever and swopped the Burris for 3 X 7 variable magnification Scout scope. for some reason setting this on the zero range uses up practically all the scopes elevation. Setting the scope for point blank at 25 yard / 100 yards on he zero rang leaves me with only 18 vertical clicks, which at 1 click for a quarter 1/4 MOA is hardly useful, leaving me with 197 clicks of depression, which is pointless.
I emailed S&K, who were very nice, but not very helpful. They said they had not encountered this before and that the best option may be shimming the scope with slivers of alloy sliced from a soda can. I looked this up on Youtube and it seemed a stop gap measure at best. I have the right tools to set the scope up properly (Torque wrench, vice and spirit levels etc,) but I am worried about damaging the scope and frankly whether the shims would just shake loose very quickly.
Any comments or suggestions or alternatives about this would be welcome.
 
Any comments or suggestions or alternatives about this would be welcome.
Click to expand...

If I am mounting a scope on a Yugo 98 I use a one piece mount. After drilling and tapping I secure the front of the mount on the front receiver ring and then check the rear base mount to the rear receiver ring. The one thing I do not expect to see is a gap, if there is a gap I have no choice but to shim the ream of the mount to the rear of the receiver; unless I grind the front scope mount mounting surface.

And then there is going into it like determining if the scope mount is parallel to the bottom of the receiver. Most of my scope mount kits index off of the bottom of the receiver.

F. Guffey
 
The best shims I ever made for a scope came from a high-brass 12ga shotgun shell. Use a dremel tool to cut off the base. Then, split the remaining brass ring by cutting length-wise 180 degrees apart. Makes 2 perfect half-moon shims.
 
Burris scope rings

I've had excellent results using Burris Signature Rings which use various thickness inserts to change the relationship of the scope to the bore, on either mount or both.
 
Many thanks to all who answered. The S&K mount I have has proprietary rings that plug directly into the mount. I am going to take it down to see if I can shim the mount rather than the rings, but it seems to me I need to raise the rear or lower the front of the scope. Would shimming the rings be a temporary measure at best and is there a danger of damaging the scope? Previously I have torqued the rings t to 18 pounds pressure.
 
Scribe said:
Many thanks to all who answered. The S&K mount I have has proprietary rings that plug directly into the mount. I am going to take it down to see if I can shim the mount rather than the rings, but it seems to me I need to raise the rear or lower the front of the scope. Would shimming the rings be a temporary measure at best and is there a danger of damaging the scope? Previously I have torqued the rings t to 18 pounds pressure.
Click to expand...

I agree, shim the mount, if possible.
Yes, "raise the rear or lower the front of the scope."
Mine have been permanent fixes, that us until I willfully change them.
Over-shimming can damage the scope tube. Use just what you need.
You can find a formula to determine your shim thickness on the interweb. Or try the table attached which came from another forum.
This is a reasonable torque range for rings (units of in•lb)
 

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  • ScopeShimTable.JPG.jpg
    ScopeShimTable.JPG.jpg
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Shimming is not a temporary fix. It's common and normal.

I use brass stock to shim scopes, but a soda can does work.

Jeff

Sent from my XT1254 using Tapatalk
 
Divide ring/base centers spacing by 3500 to get shim thickness change for a 1 MOA elevation angle change.
Click to expand...

I bolt the front of the mount to the front receiver ring and then measure the gap at the rear of the mount above the rear receiver ring. I am the fan of avoiding installing a one piece scope mount by creating a bind.

And then there are straight edges for two piece mounts.

F. Guffey
 
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