How To Shim A Scope For Windage? [Simple & Easiest Way]

What is shimming? Shimming is the process of moving your scope slightly within the ring itself to make some extra adjustment. If your riflescope doesn’t have enough windage and elevation adjustments, shimming can compensate for that.

Depending on the rifle, a shim may be a permanent solution. But how do you shim a scope for windage? Let’s find out.

Why Shim Scope Rings?

As I said earlier, shim is done to compensate for lack of adjustments. And shimming can prevent you from buying a new scope totally. A shim will be a lot cheaper than replacing the mounting system or the scope itself.

The Shim

The shim can be any flexible material that fits inside the scope ring. The most common material used in the process is cutout from plastic jugs or bottles. You can also use aluminum drink cans, brass and clothes even.

The idea is to elevate the contact between the scope and the ring. Thanks to this, the adjustments can be done more accurately for your shooting.

Don’t use a credit card as your shim. It’s too stiff and a lot thicker than necessary. Use something thin and flexible.

Shim Size

Shim size is very important. The shim shouldn’t extend past the scope rings. Make sure to cut the shim size appropriately and just long enough to hide inside the ring and make it seem like it’s part of the scope or the ring itself.

The Adjustments

A shim will give you somewhere between an inch or 5 inches at most. That too in 100 yards. How much adjustments you will get will depend on the size of the shim and bullet drop over 100 yards.

To adjust both windage and elevation, you will need two shims. If you need more scope change than that, I would rather look at different sets of scope rings. If you find yourself changing the scope rings position too often, then it’s better to change the rings all together.


Once you are sure about the adjustments and you are sure you want to shim your scope rings. Compare the size of the shim by holding it against the ring. Do not remove your scope just yet.

Once a rough estimate is done, it’s time to measure for thickness. You can use the United Kingdom Gunsmith chart to check the necessary thickness for the height you want.

Remove The Scope

After removing the scope, take some time to clean it properly. To hold the shim in its place, you can use some mild adhesive on the shim and attach it on the mount itself. After letting the shim and glue dry out, you can put your scope back in its place and start tightening it again.

But make sure to level the scope before you tighten it down entirely.

Sight The Scope

Once you install the scope you are not done. Sighting in the scope is very necessary. You just changed the position of your scope and changed the height as well. So, it’s absolutely a must for you.


And that’s about it folks. Shimming is a necessary skill that you will need to have in your disposal. It’s something that will save you a lot of hours behind tuning your scope and save you money by allowing you to keep the same mounting system.

Thanks for reading as always. Hope you found this guide useful and easy to learn. Take care and have fun.

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