Scope shim question

[Yandeltx]

New to me Wildcat MKI with 4-12X14 Vortex scope. At 25 yards I am hitting about 3/8 low of target and I am out of vertical on the scope. Here is the dumb question, if I try and shim do I shim the front or back or both. Does a little bit shim thickness go along ways on a shim??? Thanks.

 

[Coldair]

Shim the bottom of the rear ring, you can use negative film material or thin strip of soda pop can wrapped in electrical tape. 3/8"x1/4" piece.

Place at the rear closest to the zoom ring. If not enough repeat and add another shim. Don't overtighten your rings after you do this.

Adjustable mounts would be better though but this trick should get you shooting if you are careful.

CA

 

[CmdCtrl]

second on the soda can shim.

I had the same problem and just cut 2 strips out of a can to shim it up on the rear ring.

 

[Yandeltx]

When making the shim do you cut it to where if covers the 180 degrees of the mount saddle?

 

[Coldair]

https://www.pyramydair.com/blog/2013/06/scope-dope-i-hope-part-2/



CA

 

[Yandeltx]

Thanks everyone this helps me out. 

 

[jps2486]

Plastic soda bottle or milk jug works. Anything between 0.010 to 0.015 thick.

 

[Chachoze]

If you are familiar with chairgun it has a scope shim calculator to help determine the thickness needed. You may want to center your scope before using the app...

 

[Crusher]

Milk jugs plastic works well. And no you don't do the entire ring. Just the bottom half. If you have to go up more than that, I would recommend investing in some adjustable rings. 



Crusher

 

[Yarddog]

If you can get ahold of an old school automotive feeler gauge, you can use the various gauges for shim stock...and they come in various thicknesses. These were used to adjust valves back in the day. Yeah, it ruins them for their intended purpose, but hey...

 

[Revoman]

I have used a cut up 12 gauge plastic shotgun hull as a shim. It worked very well as it already has a very close radius to the scope diameter, doesn't wanna uncurl. I cut it just inboard of the ring so it was not noticeable at all. Used a black hull.

 

[Yandeltx]

Great information and I appreciate it. I installed two pieces of aluminum can hopefully I will have time to check it out tomorrow. 

 

[Yandeltx]

Anyone care go take a guess how much the two shims will effect the poi?

 

[Coldair]

???40 moa???



CA

 

[Grin_Reaver]

Did you place the shims between scope and ring or the base and ring?

Borrowed from the interwebs.

 

[elh0102]

I think that table is about right. I usually get about 1 MOA per .001" shim thickness. I've never had any problems with up to .020". If you need more, I recommend going to adjustable rings. Air guns seem to need elevation help so consistently, I have gone to adjustable rings exclusively, either the Burris Signature series, FX No Limit, or Sportsmatch adjustable. 

 

[bandg]

Not a fan of shimming myself. I believe it may put undue stress on a scope tube but others disagree and report good results with shimming. If you are going to do it then shim between scope tube and saddle of the rear mount in this case. Might also consider that you will want to shim enough to try to get your scope adjustment back near the middle of it's range. Scope will theoretically function better if it is near the center of its adjustment range. I would strongly consider adjustable mounts.

 

[Coldair]

Burris Signature series with offset inserts would be best to perfectly optically center your scope including for windage and most importantly to not mark up your scope with a lot of trial and error and time but worth it and good news BKL now has adjustable mounts... May soon to become a new favorite amoung airgunners...

CA

 

[Saltlake58]

Or, buy the FX No Limits rings or similar. Built in ability to move front or back up and down. Recommend you optically center your scope, then use the adjustable rings instead of shims so you are moving the cross hairs minimally. They aren't cheap, but well worth it.

 

[Yandeltx]

Thanks for all the replies. Two shims made from a Diet Coke can did the trick.