How To Measure Sight Height: 5 Methods And Examples

How To Measure Sight Height

Getting to know your scope height is important to determine the dope of your rifle, how accurate your weapon is and how comfortable you will be with it.

Luckily there are different methods to help you achieve this.

In this article, we will share with you the 3 methods of how to measure sight height, the formulas used for measuring scope height, the 6 tools used when mounting the scope and how the scope height affects your shooting experience.

Let dive into it

How to Measure Sight Height Quickly?

There are different methods used to measure scope height. They include the simple barrel method, the cleaning rod method, The formula-based method, among others. Let’s. Check them out.

Simplest Barrel Method

This is the simplest method of determining your scope height. it involves measuring the distance from the center of the barrel to the center of the scope or scope rings.

However, this method will give you an almost accurate answer compared to the other methods meaning precision isn’t fully guaranteed.

Cleaning Rod Method

Compared to the simple barrel method, the cleaning rod method will give you a more accurate answer.

First, you have to remove the rifle’s bolt and run a cleaning rod from the muzzle through the action to establish a center line. Ensure you use a bore guide to help you improve the accuracy.

Measure from the scope’s center to the cleaning rod’s center.

Rough Methods: Scope Tube Diameter + Some Math

How to measure sight height

Method 1

Measure the diameter of the objective lens in millimeters. (The second number in your scope’s designation, for instance the 40 in 3-9x40mm)

To account for the thickness of the scope body, add 2-4mm. and divide that result by half.

The equation will be (diameter + 2-4mm)/2 = scope ring height.

Using our very common 3-9×20 mm scope example and a middle ground of a 2 mm scope body, it looks like this: (20 + 3)/2 = 11 mm center height.

Method 2

This involves Dividing the measurement of your scope tube (usually either 1 inch or 30mm) by 2 and adding the manufacturer’s scope ring height.

For a 1.18 -inch tube = 30 mm, so half of that would be 15 mm.

Ensure you account for your objective lens, just divide your objective lens by 2 and ensure that number is smaller relative to the scope ring height and that you’ll clear the barrel.

This is different from the exact figure, but it will assist in determining scope height.

The Formula for Precisely Measuring the Scope Height

The Formula for Precisely Measuring the Scope Height

Step 1: To begin, divide the bolt diameter in half. For example, if the bolt diameter is.700″, we will get.700″/2=.350.”

Step 2: Divide the scope tube diameter in half in inches.

Step 3: Measure the distance between the top of the bolt and the riflescope’s bottom.

Step 4: Add the outcomes together. This is your scope’s height.As an example: For a Remington 700.308 rifle with a Leupold Mark 4 M1 Extended Range Tactical Riflescope, 6.5x20x50mm, mounted on it.

  1. The diameter of the bolt is 0.696 inches, which is equal to a 0.348-inch radius
  2. 30mm scope tube (1.181/2 =.591)
  1. From the top of the bolt to the bottom of the scope, there are 0.75 inches.
  2. so, the height of optic =.348 +.591 +.75 = 1.68″

The most common optic height for rifle sights is between 1.5 and 1.8 inches above the center line of the bore.

Scope Height Calculation: Personal Experience

It would be best to consider the scope tube radius, scope objective bell radius, and the thickness of your scope bases or rail when determining the required ring height.

It’s also important to consider rear sights or other modifications, as these may necessitate more height to clear the scope over the firearm.

If you can’t find the exact objective radius, add 8mm to the manufacturer’s “glass” dimension, so most 40 mm objectives are 48mm in diameter, and so on.

Selecting the Best Rings

Selecting the Best Rings for scope

Some manufacturers measure the height of the scope ring from the inner ring rim to the base. If this is the case, multiply the following values by their scope height.

  • For a 60mm scope, add 0.5 inches.
  • For a 30mm scope, add about 0.59 inches.
  • For a 35mm scope, add 0.68 inches.

The Scope Rings Height is Too High

When the scope is mounted too high, you must take an extremely awkward position to obtain a sight image, which results in more felt recoil on your shoulder. Due to the extra recoil, unnecessary high scopes suffer damage or failure.

Despite numerous attempts to zero their scope while practicing long-range shooting, several owners reported difficulty achieving accurate shots if the scope ring height was very high.

The Scope Ring Height is Insufficient

It is usually best to mount your scope as low as possible. However, you must be careful not to set it too low, as this will result in the following:

  • Difficulty in properly tightening your front scope rings. – When a scope is mounted too low, the objective lens often hits the gun barrel. The front scope rings can only be properly tightened by crimping the scope tube.
  • It makes it difficult for bolt-action rifles: Keep the handle clearance in mind when shooting a bolt-action rifle. If the bolt hits your scope, you must replace it or adjust the action.

Tools for Mounting Your Scope

A Gun Vise

A Gun Vise. How To Measure Sight Height

A gun vise is required for all types of weapon repair. They are used along with a gunsmithing screwdriver set. Gun vises are used to modify and maintain your handgun in the proper position.

Vises may hold a variety of firearms for maintenance, gunsmithing, and even cleaning. It quickly and simply facilitates mounting scopes on bolt-action, lever-action, or semi-automatic rifles.

A Torque Wrenches

A Torque Wrenches. How To Measure Sight Height

Torque wrenches apply a specific torque to fasteners such as nuts, bolts, and lag screws. 

A torque wrench is used in situations where the tightness of screws and bolts is crucial. It enables the operator to set the torque applied to the fastener to match the application’s specifications.

A Crosshair Level

A Crosshair Level

Together with your gun vise, this ensures that your horizontal crosshairs are level.

A Dab of Loctite

A Dab of Loctite

Loctite® thread lockers secure nuts, bolts, or threaded fasteners. They can be applied to any assembly. They are single-component liquids that form a strong bond between the surfaces. They are designed to hold things tight without damaging them.

A Boresight

A Boresight

A boresight allows you to visually align the bore axis of a firearm with the target, making it easier to zero the gunsight (optical or iron sights).



This will help you to zero accurately.


Why is scope height Important?

Scope height is critical to ensure that your scope is as accurate, comfortable, and long-lasting as possible.
This also allows you to have a more enjoyable shooting experience.

Which scope height do I need?

Scope heights ranging from 1.5 to 1.8 inches are ideal for your rifle. However, it is important to ensure that the scope is not in contact with any other weapon part.
The scope is also mounted low to ensure comfort when using the cheek rest.

How does scope height affect trajectory?

The height of the scope has no bearing on the trajectory. The trajectory remains the same regardless of whether the scope is mounted 1″, 6″, or none.
The bullet’s path after leaving the bore is the trajectory path. The sight height only determines the trajectory path’s position relative to the line of sight. Changing the sight height has a minimal effect on the intersections between the line of sight and the trajectory paths.

How is sight height calculated?

It’ simple:
Take the diameter of the bolt and divide it in half.
Measure the scope tube diameter and divide it in half.
Measure the distance from the top of the rifle’s bolt to the bottom of the rifle’s scope.
Add up the numbers from above.

What is sight height?

The sight height is the elevation of your sight above the bore’s centerline. It is essential for accurately calculating a firearm’s ballistics or Maximum Point-Blank Range.

How high should your scope be off the barrel?

If you are zeroed in at 100 yards, and the average deer shoulder height is 3.5 feet, your line of sight should be approximately 3.5 inches above the scope’s centerline.
However, most scopes are mounted approximately 2 to 3 inches above the barrel’s centerline. Therefore, if you are sighting in at 50 yards, you are closer to 47 yards.

How is a scope measured?

The diameter of your scope is measured at its widest part, then divided by two using a caliper.

Can we mount a scope as low as possible?

Yes, mounting the scope as low as possible will help reduce the amount of parallax error. 
Besides that, it ensures that the scope is mounted securely, which helps prevent the optics from shifting during firing, potentially leading to inaccuracy. 

Can you mount a scope too high?

Yes, however, it has a few drawbacks. You may need to raise your rifle scope to acquire your target. Mounting the scope too high may also necessitate a higher head position. This entity will cause you to lose your balance and lose track of your intended target.

What is A2 sight height?

From the center of the bore to the top of the front sight post, the A2 sight height is 2.6″. It varies slightly depending on your zero and ammo, but 2.6″ is the most commonly used value. For red dots set up for a lower 1/3 co-witness, 2.8″ is used. However, if you use a ballistic calculator, even 2.6″ or 2.5″ will give you results that are well within the margin of error for the average shooter.

How do lasers measure height?

After being emitted from the laser device, the monochromatic laser radiates through space, strikes the target, and reflects. The reflections are dispersed in all directions. However, some of them return to the device (sensor). Using this reflection, the apparatus then calculates the height.

How do you calculate sight distance?

Different methods help you calculate the sight distance; they include the Mil-Dot technique, which is based on milliradian markings. The Minute of angle technique and the short-range technique if the target is close.


You now understand how to measure scope height using the 3 different methods, the tools used when mounting your scope, and how to choose the best scope rings for your weapon.

Which method did you find easy to use? leave your comment in the comment section below and don’t forget to share the post with your friends.


My first deer at the age of 45 I joined the deer hunting fraternity a little late, but the desire to hunt has always been there. I love hunting, so I often have to deal with hunting equipment.