If you want to calculate your DOPE, you’ll need to know what your scope height is. It sounds more complicated than it really is. In reality, there are 3 different ways you can measure it. Today, we will teach you how to measure scope height using these different methods. We’re going to cover the important ones in this post.
Simplest Method
The simplest way to measure your scope height is to measure the distance from the center of the scope (you can use the scope rings as well) to the center of the barrel. This method provides for a decent measurement[1]https://en.wikipedia.org/wiki/Measurement, and it can literally be done in a few seconds.
Unfortunately, you’re trading speed for precision under this approach. Pending how skillful you can get at this method, it’s more than likely going to be less accurate when compared to the other approaches we’re going to discuss. Fortunately, there are a few other methods that are more accurate.
Cleaning Rod Method
The second method is a bit more accurate but still based on the same process. Under this approach, you need to remove the bolt of your firearm. Use a cleaning rod to get the centerline of the barrel. Now, measure the distance between the center of the cleaning rod to the center of the scope or the scope rings. This measurement is more accurate than the first-case scenario but less accurate than the third method.
When you get a new scope it is critical that you understand your optic. For example, you should know what does 4×32 scope mean. Adjusting your optic height is another basic that you should understand fully.
The formula for measuring the scope height
The last method is the most accurate and is oftentimes even used by professionals. If you just bought one of the best scope for 450 bushmaster, I would recommend this approach. It’s formula-based and a bit more complex than our first two methods. You will need some time to get used to this and make sure all the figures are accurate. We’re going to try to keep it as simple as possible, but here’s what you do:
- The first thing to do is measure the bolt diameter.
- Once you’ve figured it out, divide that number in half.
- Then, measure the scope diameter
- Divide this number in half as well.
- Measure the distance between the bottom of the scope to the top of the bolt.
- Add all of the numbers above together.
The formula will look something like this: .348 + .591 + .75 = 1.68. This example can be used for the Remington 700 and Leupold Mark 4 M1 combination. Leupold is great. In fact, they make some of the best scope for 300 wsm I have tested. To ensure your scope height is accurate, you need accurate numbers. You can use a caliper. The best option is a digital caliper because it is the most precise. There are other options available, but they may be more expensive or less exact.
Which scope height do I need?
In most cases, you will need a scope height between 1.5 and 1.8 inches. The distance is between the center of the barrel and the center of the scope or, if you like, scope rings. I personally use 30mm Scope Rings. The goal is the same. In most cases, you need the lowest setting possible. Keep in mind that the scope must not touch the barrel or any other part of the weapon. In some rare cases, usually for tactical applications, a higher scope setting is preferable. When the scope is mounted as low as possible to the rifle, it will provide a consistent picture and help you with your shots. In most examples, a height of 1.5 inches is perfect.
Keep in mind that the scope height is also affected by the power of the firearm and the length of the scope[2]https://en.wikipedia.org/wiki/Firearm. A more powerful rifle will have a stronger recoil, which can damage or even destroy the scope. As such, it should be mounted higher.
Another reason why the scope should be mounted as low as possible is the issue with low cheek rests. They are very low on most rifles, so a hunter won’t feel comfortable while using a cheek rest. This issue is eliminated with the lower scope height. When the scope is too high, you won’t feel comfortable and your accuracy will be affected.
The scope height is determined by the diameter of the scope lens. The most common option is 40 mm. Don’t forget that scopes are generally expressed in millimeters. So if you have a 34mm scope, grab some 34mm scope rings for your optic. This scope is mounted as low as possible, except with heavier barrels where the low scope rings cannot be used. The 50 mm scopes are common and popular.
They allow more light to penetrate the scope and offer better performance. However, they need to be mounted higher than 40 mm scopes. You will also need a rifle with an adjustable cheek rest. Smaller scopes such as 20–36mm will need to be mounted extremely low using low scope rings[3]https://www.tsa.gov/travel/security-screening/whatcanibring/items/rifle-scope-scope-only.
How does scope height affect trajectory?
Scope height doesn’t directly affect the accuracy, but it does affect the trajectory. If you change heights, you may need to make scope adjustments to get your optic calibrated again. Scope height determines the position between the line of sight and the trajectory (the line a bullet makes once it leaves the barrel). The scope should present to you the best point where these two lines meet. Lifting the scope just a few millimeters will affect that point.
In a nutshell, when the scope is too high, your trajectory won’t be affected, but the link between trajectory and the line of sight will be. This can affect accuracy.
Final Words
Now you know how to measure scope height and why it’s important. There are both simple and complicated processes available to measure your scope height – pick the one that works the best for your situation. Just keep in mind that scope height can have a direct correlation with how accurate you are with that scope setup. Of the three methods reviewed, we recommend the third. It is the most complicated, but it is also the most accurate.
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