Shimming a scope help, please

[SILENT SQUIRREL]

I have a Diana AM03 22 caliber break barrel
The scope is a Diana 3-9 AO on a Bullseye (sliding) mount attached to the dovetail rail.

It is shooting a very consistent 1.25" high at 25 yards.
And there is no elevation adjustment remaining.

What is my best way to shim the scope to get POI on target?
I'd like to do it and still have room in both directions on the elevation adjustment.

Thanks
Edward

[PasadenaMike]

I have a Diana AM03 22 caliber break barrel
The scope is a Diana 3-9 AO on a Bullseye (sliding) mount attached to the dovetail rail.

It is shooting a very consistent 1.25" high at 25 yards.
And there is no elevation adjustment remaining.

What is my best way to shim the scope to get POI on target?
I'd like to do it and still have room in both directions on the elevation adjustment.

Thanks
Edward

There you go
https://www.pyramydair.com/product/utg-drooper-scope-rail-11mm-to-weaver-adapter-compensates-for-droop?a=4191

[Privateer]

I'd save the money and bend the barrel myself.

[19Sheridan57]

An easy way is to use one layer of electric tape under the scope . You would have to test it to see how it works for you.

[Frank in Fairfield]

As Steve said but a layer of clean soda can would better.
What we used in the old days was 35mm negatives.

[tennx]

I got a Rex scope with a gun purchase….ran out of elevation adj….2 slivers of a mtn. Dew Can in rear ring…gave me just what I needed….@ 30 yards…..scope works as it should now…@ least on my QB 78S….good luck on your choice….

[Airnut]

I'm with Privateer I would bend the barrel. Its not as hard as you would think.

[MisterAP]

Old credit card

[longhunter]

Dumb question. Do you have the mount on backwards?

[TorqueMaster]

It is shooting a very consistent 1.25" high at 25 yards.
And there is no elevation adjustment remaining.

What is my best way to shim the scope to get POI on target?
I'd like to do it and still have room in both directions on the elevation adjustment.

I'd get the scope optically centered, then shim to the elevation needed.  I use electrical tape.
If the rings are 4" apart from each other, and at 25 yards (900 inches):
Each 0.007" layer of tape will get you 0.007"/4" x 900" = 1.575" of elevation change. 
Coke cans and 35mm film are about 0.004" thick, each will get you 0.004"/4" x 900 = 0.9" change for each layer.

If your rings aren't 4" apart just substitute the correct distance in the above.

[Roadworthy]

Shimming the scope is the LAST thing I'd try.  You stand a good chance of damaging the scope tube that way!!  The Diana ZR mount is a droop compensating mount but I think you're a bit beyond it's amount of compensation.  The mount is shipped with the stop pin retracted.  That's good, you won't need it anyhow.  If you have extended it the pin could be interfering with the ability to properly mount the scope on the dovetail.  Note there are two plates for the dovetail.  One is for 11 mm rails like the Diana has and the other is for 3/8" dovetail.  Be sure the proper one is the one you are using.  If your mount is loosened slightly and the stop pin retracted the mount should be able to slide for and aft without coming out of the dovetail.  If it can't do that the mount is probably not properly installed on the gun.  Check to make sure the scope is settled properly in the rings.

[Novagun]

I use double sided sticky tape  sometimes as well as beer can strips cut to size   the sticky tape ensure that I have no trouble with scopes moving.

[JEFFPPC]

While shimming can help it can also damage a scope. Read Roadworthy advice. If you leave the barrel alone you will need to point the scope down from rear to front. With all that being said I have shimmed scopes successfully.

[Nukall856]

SILENT SQUIRREL,
  I use electric tape to shim scopes. In some rings i have a 3 in rear 1 in front. Id rather not have to adjust up on  any scope.   With your AG hitting high, you can add shims to the front ring to bring your POI down. My Gamo Varmint hits very high unshimmed so i have 2 shims in the front ring.  Ive shimmed and shimmed and mounted and remounted, for 20 years with no problems on damaging tubes. Goodluck SS

NVak

[SILENT SQUIRREL]

Thank you to each and everyone of you that has offered a solution
After reading each post it makes sense to me to start with Roadworthy's advice regarding the Bullseye mount.

FWIW
I did not do the initial install.
The gun came to me with scope & Bullseye already mounted,
So, I will start from scratch & remove, optically center (again) and reinstall.
And I should probably search for Bullseye ZR install & user instructions, as I had no idea it is a compensating mount
Just to keep longhunter involved I may try putting things on backward.
Can you find an LOL in that statement?

And of course, will update this thread

Thanks again guys
Edward

[Airnut]

I coud be wrong here but this is how I see it.
If it is shooting high and you ran out of scope adjustment your barrel more than likely is bent upwards. The zr mount has .4 droop compensation built in. So when properly mounted it would make the problem worst. I take it that the gun was second hand. I suspect the last owner may have had a Oh s#@t moment once when cocking the gun and it bent the barrel.
Usually it's not hard to see the upward bend in the barrel with the naked eye. If the barrel is not bent then you have a issue with the lock up. Weather it be mechanical or bad machine work.
I myself would identify the problem and correct it if possible and only shim the scope as a last resort. But that's just me.

[Back_Roads]

 Here is the proper mount orientation just incase.

[SILENT SQUIRREL]

Here is the proper mount orientation just incase.

Thanks, Jim
That is the direction mine is mounted.
Edward

[SILENT SQUIRREL]

Here is the proper mount orientation just incase.

Thanks, James
That is the direction mine is mounted.
Edward

[TorqueMaster]

I coud be wrong here but this is how I see it.
If it is shooting high and you ran out of scope adjustment your barrel more than likely is bent upwards. The zr mount has .4 droop compensation built in. So when properly mounted it would make the problem worst. I take it that the gun was second hand. I suspect the last owner may have had a Oh s#@t moment once when cocking the gun and it bent the barrel.
Usually it's not hard to see the upward bend in the barrel with the naked eye. If the barrel is not bent then you have a issue with the lock up. Weather it be mechanical or bad machine work.
I myself would identify the problem and correct it if possible and only shim the scope as a last resort. But that's just me.

This is the along the same thoughts I have been having.  Assuming any mechanical issues are not present... the gun is hitting high, and the with that mount the scope is pointing low, way low.  If the barrel is bent upwards, you may be better off installing the mount "backwards" and see it that gets you close to where you want to be.  Or possibly the barrel is straight and you just need a mount with no correction?  Have any regular rings handy to give a test run?