How to Measure Scope Ring Height?

Everyone wants a comfortable and accurate shooting experience and this is literally impossible if you have the wrong size of scope ring. I know that it can be hard to know which scope ring is right for you, however, it is not impossible for sure.

In this guide, I will go into the details, and help you determine the suitable size of scope ring so that you get a comfortable viewing as well as shooting experience. I will try my level best to explain it in the simplest possible ways. So, let’s go.

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Equipment/Tools Needed to Measure Scope Ring Height

If you’re an experienced person, then you might think that finding the exact scope ring is a straightforward process. In fact, many experiences don’t even measure it because they guess it by seeing the scope. But newbies who are relatively newer to scopes must have some tools to avoid any small mistakes or errors.

• Calipers
• A level
• A base or rail

A level is used to ensure that the rifle is level during the measurement process. Keep in mind that an uneven rifle can cause the scope to be mounted at an incorrect angle, which can affect accuracy.

Similarly, the calipers and base/rails are also important equipment that helps ensure in precise measurement. I hope that you’ll be able to arrange these tools. So let’s drill down and go into more advanced information.

How to Measure the Scope Ring?

One thing that highly affects your viewing and shooting experience is the height of the scope ring. Inaccurate height is something that can affect your aim. A scope that is mounted too high or too low can affect the accuracy and make it difficult to get a proper sight picture. 

But don’t worry, as I have got your back. In the section below, I will guide you through the exact process for a measure the height of the scope ring so that you get perfect accuracy every time you shoot or aim at something.

Also Read: Where Are SWFA Scopes Made?

1- Measuring Scope Ring Height on a Rifle with No Scope

If the rifle does not have a scope mounted, measuring the scope ring height is straightforward. However, I don’t recommend you measure the height by unmounting the scope as chances become high that you’ll get inaccurate readings or measurements.

However, if you feel comfortable with this then measure the height of the rifle’s receiver from the base to the center of the bore. This is the starting point for determining the height of the scope rings needed for the rifle.

Once you’ve measured the eight of the rifle’s receiver from the base to the center of the bore then note it down on a copy so that you don’t forget it. Keep in mind that slight mistakes in numbers can give you inaccurate measurements so be careful.

The next step is to measure the outside diameter of the rifle’s objective bell. This is the widest part of the scope’s front lens. This measurement will help determine the height of the scope rings needed for the rifle.

So, now you will have two measurements if you’ve followed the above-given instruction. It is time to do some final calculations to find the exact height of the scope ring. 

• Subtract the measurement of the outside diameter of the rifle’s objective bell from the measurement of the height of the rifle’s receiver from the base to the center of the bore. This will give you the difference between these two measurements.
• Divide the difference by 2 to find the midpoint.
• Add the midpoint to the measurement of the outside diameter of the rifle’s objective bell.

The resulting value will give you the exact height of the scope rings needed for your rifle. This calculation takes into account the distance between the center of the bore and the top of the objective bell, ensuring the scope is properly aligned with the rifle’s barrel.

2- Measuring Scope Ring Height on a Rifle with a Scope

If the rifle already has a scope mounted, measuring the scope ring height is even easier. In fact, I highly recommend you measure the scope ring height by mounting the scope on the riffle as it will give you more accurate and practical readings and measurements. 

First of all, I suggest you measure the distance from the top of the scope’s base to the center of the scope’s bore. This measurement is the height of the scope above the rifle’s receiver.

Once you have measured the height of the scope above the rifle’s receiver, then start measuring the outside diameter of the rifle’s objective bell. This step is common no matter if you measure the scope ring height of the mounted or unmounted scope.

Subtract the measurement of the height of the scope above the rifle’s receiver from the outside diameter of the objective bell. The resulting value is the approximate height of the scope rings needed for your rifle.

How to Calculate the Scope Ring Height?

If the above section, I gave you more of a theoretical answer that definitely will help you in understanding to calculate the height of the scope ring. But I am not letting you go with that. In fact, in the section below, I am going into more depth and helping you understand how you will calculate the scope ring height accurately.

Understanding Radius

In order to calculate the height, it is important for you to know about the radius. It might sound something like a big word, but it’s actually quite simple. Imagine you have a circle, like a pizza. 

The radius is like half of that pizza. So, if you know the diameter of the circle (which is the whole pizza), you can find the radius by dividing it by 2. Easy, right? There cannot be any more simple explanation of radius. I am sure!

Note: You might consider that knowing or understanding the radius is not important. If you’re thinking like that, you’re wrong. Having a basic knowledge of radius is very important as we have to calculate the radius in the section below. This is why I explained radius in the simplest possible way.

Finding the Objective Radius

Alright, let’s use what we’ve learned so far. Take the diameter of your scope’s objective and divide it by 2. This will give you the radius of the objective. Remember, the objective is the big glass part at the front of your scope. 

If you’ve seen the scope, then you already know that there will be glass in the front of the scope. This glass present on the front of the scope is called an objective lens. You will need to calculate the radius of this objective lens glass.

Calculating Tube Radius

Now, let’s move on to the tube. Measure the diameter of your scope tube and divide it by 2. This will give you the radius of the tube. The tube is the part of your scope that holds everything together. 

Now, I am sure that you’ll understand why I initially guided you about radius because it was an important term and without understanding you would not have been able to understand the whole technical measurement and jargon.

Base or Rail Height

Next, we need to know the height of your scope bases or rail. I suggest you to measure the thickness of your bases or rail at the front of the rifle receiver. This will help us determine how high the rings need to be.

Plug in the Numbers and do simple calculations

Now comes the fun part—putting everything that we have measured in the above section together.  Subtract the tube radius and the base or rail height from the objective radius. This will give you the minimum ring height required for your scope. 

You have all the measurements on hand. In the section below, I am going to give you a simple formula that will help you find out the minimum scope ring height.

Minimum Scope Ring Height = Objective Radius − Tube Radius −  Base or rail height

Use this formula and find out the exact or at least minimum height of the ring scope that you’ll need to get perfect accuracy by using your rifle scope. I hope that this formula will make your life easier.

Factors to Consider Before Choosing the Right Scope Ring

There are a few things that you must consider if you’re going to an optics store to buy the scope ring. In the section below, I will go into the explanation and help you understand the important factors and help you save yourself from making the wrong decision.

1. Rifle’s Mounting Platform

Having basic knowledge about the rifle’s mounting platform is key. Different rifles have different mounting platforms, such as Picatinny or Weaver rails. So, you must know the rifle’s mounting platform and choose scope rings that are compatible with your rifle’s mounting platform to ensure a secure fit.

2. Scope’s Size

The size of your scope is another important consideration. Different brands produce scope in different sizes and each size requires its specific height of the ring of scope. You need to ensure that the rings you choose are the correct size for your scope’s tube. Most scopes come with a 1-inch or 30-mm tube diameter, so make sure you choose rings that match your scope’s tube diameter.

3. Objective Lens Size

The size of your scope’s objective lens is also an important factor. You can know the size of the objective lens of your scope by reading the specification of your scope. The larger the objective lens, the higher your scope will sit above the rifle’s receiver. It is important to choose rings that will provide enough clearance for your scope’s objective lens.

Frequently Asked Questions