If you’re new to rifles, the numbers on a scope can look like a secret code. Understanding what rifle scope numbers mean is the first step to choosing the right optic and using it effectively.
These numbers tell you about the scope’s magnification, lens size, and other key features. They are the basic specs that determine how your scope will perform in the field or on the range. Let’s break them down so you can shop and shoot with confidence.
What Do Rifle Scope Numbers Mean
At its core, the numbers describe two primary things: magnification and objective lens diameter. You’ll see them written in a format like “3-9×40” or “4×32.” This is the scope’s model designation, and it holds the key to it’s performance.
The First Number: Magnification Power
The number or numbers before the “x” refer to magnification. This tells you how much closer the target will appear compared to your naked eye.
- A “4×32” scope has a fixed power of 4x. The target looks four times closer.
- A “3-9×40” scope is a variable-power scope. You can adjust it from 3x magnification up to 9x magnification. This gives you flexibility for different situations.
The Second Number: Objective Lens Diameter
The number after the “x” is the diameter of the front (objective) lens in millimeters. In a “3-9×40” scope, the objective lens is 40mm wide.
- A larger lens generally gathers more light. This can mean a brighter image, especially in low-light conditions like dawn or dusk.
- However, a larger lens also means a heavier scope and it may need higher mounting rings to clear the rifle barrel.
Putting It All Together
So, a “3-9×40” scope means: variable magnification from 3x to 9x, with a 40mm objective lens. A “6-24×50” scope offers higher magnification for long-range shooting and a very large 50mm light-gathering lens.
Other Important Numbers on a Scope
The main numbers aren’t the whole story. You’ll often see other specifications listed.
Field of View (FOV)
This is the width of the area you can see through the scope at a specific distance, usually given in feet at 100 yards. A wider field of view makes it easier to track moving targets or scan an area. Higher magnification narrows the field of view.
Eye Relief
This is the critical distance your eye must be from the rear lens to see the full picture. It’s measured in inches. Longer eye relief (3-4 inches) is essential for high-recoil rifles to prevent the scope from hitting your eyebrow (“scope bite”).
Adjustment Click Value
Scopes have turrets to adjust for windage (left/right) and elevation (up/down). The click value tells you how much each “click” of the knob moves the point of impact. Common values are 1/4 MOA (Minute of Angle) or 0.1 MRAD (Milliradian).
- 1/4 MOA ≈ 1/4 inch at 100 yards.
- 0.1 MRAD ≈ 0.36 inches at 100 yards.
How to Choose the Right Scope Numbers for Your Needs
Picking a scope isn’t about getting the biggest numbers. It’s about matching the specs to your intended use.
- Close-Range Hunting (Woods): Choose a low-power, wide-field scope. A 1-4×24 or 2-7×32 is excellent for fast target acquisition at short distances.
- Medium to Long-Range Hunting: A versatile variable scope like a 3-9×40 or 4-12×50 is the most popular choice. It handles most common shooting distances.
- Long-Range Precision/Target Shooting: You’ll want higher magnification. Look for scopes like 5-25×56 or 6-24×50. These allow for precise aiming at small, distant targets.
- .22 LR or Plinking: A simple fixed 4x scope or a low-power variable like a 2-7×32 is often perfect and affordable.
Common Mistakes to Avoid
When learning what rifle scope numbers mean, it’s easy to get carried away.
- Over-Magnifying: Too much power can make the image shaky, narrow your field of view drastically, and make finding a target at practical hunting ranges difficult. For most big-game hunting under 300 yards, you’ll rarely need more than 8x or 9x.
- Ignoring Eye Relief: Always check the eye relief, especially for magnum calibers. Insufficient eye relief is a safety hazard.
- Forgetting About Weight and Size: A huge 50mm or 56mm scope is heavy and can make a rifle cumbersome to carry all day. Balance performance with practicality.
Mounting and Using Your Scope
Once you’ve chosen your scope, proper mounting is crucial. Use a quality set of rings and a base. If your not confident, have a gunsmith mount it for you. After mounting, you’ll need to zero the scope.
- Bore Sighting: Roughly align the scope with the rifle’s barrel to get on paper. You can use a laser bore sighter or do it visually.
- Fire a Group: Shoot a 3- or 5-shot group at your desired zero distance (e.g., 100 yards).
- Adjust the Turrets: Use the knobs to move the crosshairs to the center of your shot group. Remember your click values (e.g., 16 clicks of 1/4 MOA to move 4 inches at 100 yards).
- Repeat: Fire another group to confirm your zero. Make fine adjustments as needed.
FAQ Section
What does 3-9×40 mean on a rifle scope?
It means the scope has variable magnification from 3 power to 9 power, and it has a 40-millimeter diameter objective lens.
Is a higher magnification scope always better?
No, not always. Higher magnification reduces field of view, amplifies shake, and can be slower to use. Choose magnification based on your typical shooting distance.
What does a 4×32 scope mean?
It is a fixed-power scope with 4x magnification and a 32mm objective lens. It’s a simple, durable option for shorter ranges.
How important is objective lens size?
It affects light gathering and, to some extent, image brightness. But lens quality (glass and coatings) is just as important. A high-quality 40mm lens can outperform a cheap 50mm lens.
What is the best all-around rifle scope magnification?
For a huge variety of hunting, the 3-9×40 scope is considered the most versatile and popular all-around choice.
What do the MOA numbers on a scope mean?
MOA refers to the adjustment value of the turrets. 1/4 MOA means each click moves the point of impact by 1/4 inch at 100 yards (approx. 1/2 inch at 200 yards, etc.).
Now you know what rifle scope numbers mean. You can look at any scope’s specifications and understand it’s basic capabilities. Remember to balance the numbers with your actual needs, budget, and the quality of the scope’s construction. The right scope, properly mounted and zeroed, will make you a more effective and confident shooter.