If you’re new to rifles or optics, the numbers on rifle scopes can look like a secret code. Understanding what do numbers on rifle scopes mean is the first step to choosing the right one and using it effectively.
This guide breaks it down into simple terms. We’ll look at magnification, objective lens size, and all the other markings you’ll see.
What Do Numbers On Rifle Scopes Mean
At its core, the numbers describe two main things: how much it magnifies and how much light it gathers. You’ll usually see them written in a format like “3-9×40” or “4×32.” Let’s start with the most common format.
The Basic Format: Magnification x Objective Lens
The classic numbers, like “3-9×40,” tell you the scope’s key specs. The number before the “x” is about zoom. The number after the “x” is about light.
- Magnification (the first number/s): This tells you how many times closer the target appears. A “4x” scope makes a target look four times closer than it does with your naked eye.
- Objective Lens Diameter (the second number): This is the lens at the front of the scope, measured in millimeters. A larger number (like 50mm) gathers more light than a smaller one (like 28mm), which can mean a brighter image in low light.
Fixed Power vs. Variable Power Scopes
Scopes come in two main magnification styles, and this changes how the numbers look.
- Fixed Power (e.g., 4×32): These have one set magnification. They are simple, reliable, and often more affordable. The “4x” is fixed; you can’t zoom in or out.
- Variable Power (e.g., 3-9×40): These are zoom scopes. The “3-9x” means you can adjust the magnification from 3 times up to 9 times closer. They offer great flexibility for different shooting distances.
Breaking Down a Common Example: 3-9×40
Let’s use a very popular hunting scope as our example.
- 3-9x: This is a variable power scope. At its lowest setting, it magnifies 3x. At its highest setting, it magnifies 9x. You turn a ring (the magnification ring) to change between them.
- 40: This is the diameter of the objective (front) lens in millimeters. A 40mm lens is a good balance, offering decent light gathering without making the scope too heavy or bulky.
So, a 3-9×40 scope gives you a flexible zoom range for mid-distance shooting, like for deer hunting in woods or fields.
Other Important Numbers and Markings
Scopes have other numbers that are just as important for performance.
Field of View (FOV)
Often listed in feet at 100 yards, this tells you how wide an area you can see through the scope at a specific distance. A wider field of view (e.g., 30 ft at 100 yds) makes it easier to track moving targets. Higher magnification usually means a narrower field of view.
Eye Relief
This critical number, measured in inches, is the distance your eye must be from the rear lens to see the full picture. Longer eye relief (3.5 inches or more) is safer for powerful rifles and more comfortable for eyeglass wearers. Shorter eye relief can mean getting hit in the eye by the scope under recoil.
Adjustment Turrets and Click Values
The dials on top and side of the scope for adjusting your point of impact are called turrets. They are marked with numbers and often say “1/4 MOA” or “1/2 MOA.”
- MOA (Minute of Angle): A unit of angular measurement. Roughly, 1 MOA is about 1 inch at 100 yards.
- Click Value: “1/4 MOA” means each audible “click” when you turn the dial will move the point of impact by 1/4 inch at 100 yards (or 1/2 inch at 200 yards, etc.). This is how you zero your rifle.
How to Choose Based on the Numbers
Matching the scope numbers to your intended use is key. Here’s a simple guide.
- Close-Range / Brush Hunting (e.g., wild hog): A low-power, wide-field scope like a 1-4×24 or a fixed 2.5×20 is ideal. You need quick target acquisition, not high zoom.
- General Big Game Hunting (e.g., deer, elk): The classic 3-9×40 or a 4-12×50 are excellent, versatile choices. They handle woods and longer field shots.
- Long-Range Precision / Varmint Hunting: You’ll want higher magnification. Look for variable scopes like 6-24×50 or 4-16×44 to see small targets clearly at long distances.
- .22 LR Plinking & Small Game: A simple fixed 4×32 or a low-power variable like 2-7×32 is perfect and cost-effective.
Remember, a huge objective lens (like 56mm) requires higher scope rings to clear the rifle barrel, which can effect your cheek weld. Always balance size with practicality.
Common Mistakes to Avoid
When you’re looking at scope numbers, keep these pitfalls in mind.
- Over-Magnifying: More zoom isn’t always better. High magnification amplifies shaky hands, has a narrower field of view, and gathers less light at the highest setting. Choose a range that fits your real-world shooting.
- Ignoring Eye Relief: For a high-recoil rifle like a .300 Win Mag, don’t choose a scope with short eye relief. It’s a safety issue.
- Forgetting About Weight and Size: A big 5-25×56 scope is overkill and heavy on a lightweight mountain hunting rifle. Match the scope to the rifle’s purpose.
By paying attention to all the numbers, not just the magnification, you’ll make a much better choice. Its worth taking your time to understand them all.
FAQ Section
What does 4×32 mean on a rifle scope?
It means a fixed 4-power magnification with a 32mm diameter objective lens. It’s a common, simple scope for shorter ranges.
Is a 3-9×40 scope good for 100 yards?
Yes, a 3-9×40 is an excellent all-around scope for 100 yards. At 100 yards, 9x magnification provides plenty of detail for precise shot placement on a target or game animal.
What does MOA mean on a scope?
MOA stands for Minute of Angle. It’s the unit of measurement used for the windage and elevation adjustments on your scope turrets. Most scopes adjust in 1/4 or 1/2 MOA “clicks” per turn.
What is better, a 50mm or 40mm objective lens?
A 50mm lens gathers more light, which can be beneficial in very low dawn or dusk conditions. However, it makes the scope heavier and requires taller mounting rings. A 40mm offers a great balance of performance and size for most hunters.
What do the numbers on scope rings mean?
Scope ring numbers (like “Medium” or “High”) or measurements (like 1.00″) refer to their height from the rifle’s rail to the center of the ring. This height must be chosen to fit the objective lens diameter of your specific scope so it doesn’t touch the rifle barrel.