Shimming a rifle scope is a process used to ensure that your scope is mounted properly and securely. It involves using special washers or spacers called shims that are placed between the scope and the rifle’s mounting base or rail. This is done to ensure that the scope is aligned with the bore of the rifle, which is necessary for proper accuracy and precision. It is applicable across all brands.
Advantages and Disadvantages of Shimming
Shimming your rifle scope has some advantages and disadvantages. The main advantage of shimming is that it allows you to make small adjustments to the scope’s alignment without having to loosen and re-tighten the scope rings. This can be especially useful if you’re trying to make small adjustments to the scope’s elevation or windage. Another advantage of shimming is that it can help to alleviate some of the stress and strain on the scope rings, which can be beneficial if you’re mounting a larger or heavier scope.
On the downside, shimming can be a bit of a hassle. You’ll need to take the time to measure the gap between the base and the scope, then cut and shape the shims accordingly. This can be a bit of a fiddle, and you may find yourself having to adjust the shims multiple times until you get the alignment just right. Furthermore, shimming may not be necessary if you’re using a lightweight scope.
The best type of shims to use for shimming a rifle scope are aluminum shims. These are lightweight and durable, and are easy to cut and shape. They’re also relatively inexpensive and easy to find. If you’re looking for something a bit more substantial, you can also opt for steel shims. These are more durable and can provide a more secure fit, but they’re also more expensive and more difficult to work with.
The best brand of shims to use for rifle scopes depends on the scope, but some of the most popular brands include Wheeler Engineering, Brownells, Leupold, and Burris.
How to install shims
1. Remove the existing scope from your firearm.
2. Measure the distance between the rear of the scope and the front of the scope mount using a ruler or caliper. This measurement is known as the “scope height”.
3. Determine the thickness of the shims required to achieve the desired scope height.
4. Place the shims on top of the scope mount and align them so that they are centered on the scope tube.
5. Secure the scope mount to the rifle with the screws provided and tighten them evenly.
Hope this assists your aim and precision – Happy Shooting!

An optics enthusiast – I love bird watching as well as wildlife. Originally from South Africa, I moved to the UK at a young age. I love reviewing the latest binoculars as well as traveling. I work as a comms consultant during the day. My plan is to travel across the world so building up to that goal.