How To Read Scope Numbers

When it comes to rifle scopes, understanding the scope numbers is crucial for any shooting enthusiast. Scope numbers provide important information about the scope’s capabilities, which can greatly impact your shooting accuracy and overall experience. In this article, we will delve into the details of scope numbers and how to decipher them effectively. Whether you are a seasoned shooter or a beginner, this guide will help you make the most of your rifle scope and improve your shooting performance.

Scope NumberMeaning
1The first level of scope, typically the broadest
1.1A sub-level of scope, indicating a narrower focus
1.1.1A further sub-level of scope, indicating more detail
1.2Another sub-level of scope, distinct from 1.1
2The second level of scope, typically narrower than 1
2.1A sub-level of scope within the second level
2.2Another sub-level of scope within the second level
3The third level of scope, typically the most specific
3.1A sub-level of scope within the third level
3.1.1A further sub-level of scope within the third level
….Additional levels of scope can continue as necessary

Understanding the Basics of Scope Numbers

Magnification (Zoom) Power

One of the most prominent numbers on a scope is the magnification power, often represented as a range such as 3-9x. The first number indicates the lowest magnification level, while the second number indicates the highest. For instance, a 3-9x scope allows you to zoom in from three times the original size up to nine times closer. A higher magnification power is beneficial for long-range shooting, while lower settings are ideal for close-range or fast-moving targets.

Objective Lens Diameter

The objective lens diameter is the number following the ‘x’ in the scope specification. For example, in a 3-9×40 scope, the objective lens diameter is 40mm. A larger objective lens allows more light to enter the scope, resulting in a brighter image, especially in low-light conditions. However, larger objective lenses may increase the overall weight and size of the scope.

Decoding Reticle Patterns

Duplex Reticle

The duplex reticle is one of the most popular and straightforward reticle designs. It features a simple crosshair with thicker outer lines and finer inner lines. This design allows for quick target acquisition while still providing precise aiming points for various distances.

Mil-dot Reticle

The mil-dot reticle is widely used in tactical shooting and long-range precision shooting. It consists of dots and hash marks evenly spaced along the crosshair’s vertical and horizontal lines. These dots help measure the distance to the target and compensate for bullet drop and windage.

Scope Adjustment Values

MOA (Minute of Angle)

MOA is a unit of angular measurement used to adjust the scope’s point of impact. One MOA is approximately 1 inch at 100 yards. Most scopes offer ¼ MOA or ⅛ MOA adjustments, meaning each click will move the point of impact by a quarter or an eighth of an inch at 100 yards, respectively.

MRAD (Milliradian)

MRAD is another unit of angular measurement commonly used for scope adjustments. One MRAD is approximately 3.6 inches at 100 yards. MRAD adjustments are popular among military and tactical shooters due to their simplicity in calculating adjustments for long-range shots.

Parallax Adjustment

Parallax is an optical illusion that causes the reticle to appear to move when you shift your eye’s position behind the scope. High-end scopes come with a parallax adjustment feature that allows you to eliminate parallax error, resulting in a more accurate shot.

Eye Relief and Exit Pupil

Eye Relief

Eye relief refers to the distance between your eye and the scope lens at which you can see the full field of view. It’s crucial for safety and comfort, especially in powerful rifles with significant recoil. Longer eye relief is preferred to avoid the risk of scope eye injuries.

Exit Pupil

The exit pupil is the small, bright circle of light you see when holding the scope at arm’s length. To get the most out of your scope’s light-gathering capabilities, choose an exit pupil size close to the diameter of your pupil in low-light conditions.

Frequently Asked Questions [FAQs]

Can I use a higher magnification scope for close-range shooting?

While it’s possible, it might not be the most practical choice, as higher magnification scopes have a narrower field of view.

What is the benefit of an illuminated reticle?

An illuminated reticle helps improve target visibility in low-light conditions.

Can I use MOA adjustments with an MRAD reticle?

Yes, you can, but it might require conversions when making adjustments.

Is parallax adjustment essential for all shooting scenarios?

For most casual shooting scenarios, parallax adjustment is not critical, but it can be beneficial for precision shooting.

How do I maintain my scope to ensure longevity?

Regularly clean the lenses, protect the scope from extreme weather conditions, and store it properly when not in use.


Mastering the art of reading scope numbers is essential for optimizing your shooting experience. Understanding the magnification power, reticle patterns, scope adjustment values, parallax, eye relief, and exit pupil will equip you with the knowledge needed to select the perfect scope for your shooting needs.

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