If you’re new to riflescopes, the array of numbers and markings can seem like a secret code. Understanding what the numbers on a rifle scope mean is the first step to using it effectively. This guide will break down the common specifications like magnification, objective lens size, and reticle adjustments in simple terms. You’ll learn how to read them and, more importantly, how they affect your shooting.
What Do The Numbers On A Rifle Scope Mean
The primary numbers on a rifle scope describe its magnification and objective lens size. You’ll usually see them formatted as two numbers separated by an “x,” like 3-9×40 or 4×32. The first number(s) refer to magnification, and the second number is the diameter of the objective lens in millimeters. Let’s look at each part.
Magnification: The First Number(s)
Magnification tells you how much closer the target appears compared to the naked eye. A scope marked “4x” makes the target look four times closer. If the first number is a range, like “3-9x,” it means the scope is variable. You can adjust the magnification from 3 times to 9 times closer.
- Fixed Power (e.g., 4x): Simple, reliable, and often lighter. Great for consistent shooting at known distances.
- Variable Power (e.g., 3-9x): Offers flexibility. Use lower power for closer shots or wider fields of view and higher power for precision at longer ranges.
Objective Lens Diameter: The Second Number
The number after the “x” (like the “40” in 3-9×40) is the objective lens diameter in millimeters. This lens is at the front of the scope. A larger lens generally gathers more light, which can mean a brighter image in low-light conditions. However, a bigger lens also means a heavier scope and may require higher mounting rings.
Other Common Markings and Thier Meaning
Scopes often have other important numbers etched on them. These are just as crucial for proper use.
Field of View (FOV)
Often listed in the manual or on the box, FOV is the width of the area you can see through the scope at a specific distance, usually 100 yards. A wider FOV makes it easier to track moving targets. Higher magnification typically results in a narrower field of view.
Eye Relief
This is the distance your eye must be from the rear lens to see the full picture. It’s critical for safety, especially on high-recoil rifles. A scope might say “3.5-4 inch eye relief.” Always ensure your scope is mounted so you have a full view without risk of the scope hitting your eyebrow during recoil.
Adjustment Turrets: MOA or MRAD
The turrets on top and side of the scope for adjusting point of impact are marked with clicks. The numbers indicate the system: MOA (Minute of Angle) or MRAD (Milliradian). Each click moves the bullet’s impact a specific amount at 100 yards (e.g., 1/4 MOA or 0.1 MRAD). The numbers help you keep track of how much you’ve adjusted.
Putting It All Together: Reading a Scope Model
Let’s decode a common scope specification: 3-9x40mm.
- 3-9x: This is a variable power scope. You can twist the magnification ring to make your target appear 3 times to 9 times closer.
- 40mm: The objective lens at the front is 40 millimeters in diameter. It should provide a good balance of light gathering without being overly bulky.
- You might also see 3-9×40 SF where “SF” could stand for Side Focus, a parallax adjustment feature.
Another example is a 6-24×50 FFP MRAD scope. This is a high-magnification optic (6x to 24x) with a large 50mm objective lens. “FFP” means the reticle is in the First Focal Plane, so it grows and shrinks with magnification, and “MRAD” denotes the turret adjustment system.
How to Choose Based on the Numbers
Your intended use should guide your choice. The numbers arn’t just specs; they dictate performance.
- Big Game Hunting in Woods: A 1-4x or 2-7x scope with a wider field of view is ideal for quick shots at shorter ranges.
- Long-Range Target Shooting: Look for higher variable magnifications like 5-25x, a large objective lens (50mm+), and a precise turret system (MOA or MRAD).
- Varmint Hunting: A scope in the 4-12x or 6-18x range allows for precise shot placement at medium distances.
- All-Around Rifle: The classic 3-9×40 remains a incredibly popular and versatile choice for many hunters.
Common Mistakes to Avoid
When interpreting scope numbers, a few pitfalls can lead to a poor setup.
- Over-Magnifying: More power isn’t always better. High magnification amplifies shake, narrows your field of view, and can make finding a target difficult. Choose a scope with a magnification range suitable for your typical shooting distances.
- Ignoring Eye Relief: Mounting the scope too far forward or back leads to a poor sight picture and can be dangerous. Always check the manufacturer’s specified eye relief during mounting.
- Misunderstanding Adjustments: Confusing MOA and MRAD clicks can cause significant misses at long range. Decide on one system and stick with it for consistency across your gear.
FAQ: Your Questions Answered
What does 4×32 mean on a rifle scope?
It means a fixed 4x magnification with a 32mm diameter objective lens. It’s a simple, common setup for .22 rifles or shotguns.
What is the difference between 3-9×40 and 4-12×50?
The 3-9×40 offers a wider field of view at low power (3x) for closer shots. The 4-12×50 starts at a higher minimum magnification (4x) but offers more top-end power (12x) and a larger objective lens (50mm) for potentially better performance in low light.
What do the numbers on scope turrets mean?
They indicate the adjustment system (MOA/MRAD) and track the number of clicks or rotations you’ve made. For example, a turret marked “1/4 MOA” moves the point of impact 1/4 inch at 100 yards per click.
Is a bigger objective lens always better?
Not always. While it gathers more light, it adds weight, size, and may require higher mounts. For most daytime hunting, a 40mm or 44mm lens is sufficient. Larger lenses (50mm+) are beneficial in very low light.
What does “FFP” or “SFP” mean on a scope?
These refer to the Focal Plane of the reticle. In a First Focal Plane (FFP) scope, the reticle size changes with magnification. In a Second Focal Plane (SFP) scope, the reticle stays the same size, so holdover marks are only accurate at one specific magnification (usually the highest).
Now you can look at a rifle scope and understand it’s basic capabilities. Remember, the best scope is the one with numbers that match the type of shooting you do most often. Take your time to consider where and how you’ll use it, and you’ll be able to choose a optic that truly enhances your accuracy and enjoyment.