If you’re new to long-range shooting, you’ve probably seen the term “MOA” on rifle scope specifications. Understanding what is MOA on a rifle scope is fundamental to making accurate shots at distance. It’s not just a marketing term; it’s the language of precision, dictating how you adjust your crosshairs and compensate for bullet drop and wind. This guide breaks it down in simple terms, so you can use your scope effectively.
Think of MOA as a unit of measurement for angular distance. It stands for “Minute of Angle.” There are 60 minutes in one degree, just like there are 60 minutes in an hour. One MOA is 1/60th of a degree. While that’s a tiny angle, it translates to a specific size at a given range, which is what makes it so useful for shooting.
What Is MOA On A Rifle Scope
On your rifle scope, MOA applies in two critical ways: the adjustment turrets and the reticle. The turrets are the dials on the top and side of the scope for windage and elevation. Most scopes have turrets that click, and each click typically moves the point of impact by a certain fraction of an MOA. Common values are 1/4 MOA, 1/2 MOA, or 1 MOA per click. The reticle might also have markings spaced in MOA, helping you hold for wind or estimate range without touching the dials.
How Big is One MOA at Distance?
The practical magic of MOA is its relationship to distance. While it’s an angle, we often talk about it as a linear measurement. A common approximation is that 1 MOA equals about 1 inch at 100 yards. But that’s just the start. Because it’s an angle, it expands linearly with distance.
* At 100 yards, 1 MOA ≈ 1 inch.
* At 200 yards, 1 MOA ≈ 2 inches.
* At 500 yards, 1 MOA ≈ 5 inches.
This predictable growth is why MOA is so powerful. If you know your bullet drops 25 inches at 500 yards, and your scope adjusts in 1/4 MOA clicks, you can calculate the exact correction needed.
MOA vs. MRAD: What’s the Difference?
You’ll often see scopes and reticles in either MOA or MRAD (Milliradian). Both are angular units, but they use different “math.” MRAD is based on the metric system and is often considered simpler for calculating adjustments, especially with meters. MOA is rooted in inches and yards. Neither is inherently better; it’s about preference and consistency. The critical rule is to match your scope’s turret units to your reticle units (MOA/MOA or MRAD/MRAD) to avoid confusing math on the range.
How to Use Your MOA Scope Turrets
Let’s walk through a real example. Say you’re zeroed at 100 yards, and you shoot at a target 300 yards away. Your bullet hits 18 inches low.
1. Determine the error in inches: Your impact is 18 inches low.
2. Calculate the error in MOA at that distance: Remember, at 300 yards, 1 MOA is about 3 inches. So, 18 inches ÷ 3 inches per MOA = 6 MOA of correction needed.
3. Apply the correction using your turrets: If your scope has 1/4 MOA clicks, you need to figure out how many clicks make 6 MOA. Since 4 clicks = 1 MOA, you need 6 MOA x 4 clicks = 24 clicks.
4. Dial the adjustment: Turn your elevation turret “UP” 24 clicks. Your next shot should now be on target, assuming you calculated correctly and the wind is calm.
Understanding MOA Reticles
Many modern scopes have reticles with hashmarks or dots spaced in MOA. These are not for looks; they’re tools for holds and ranging. If you see the bullet impact a certain number of hashmarks off target, you can use that to adjust without dialing. For instance, if a hashmark represents 2 MOA and your bullet hit 2 hashmarks to the left, you know you need a 4 MOA windage correction (if shooting at 100 yards, that’s ~4 inches).
What Does “MOA Guarantee” Mean for a Rifle?
You might see rifles advertised with a “1 MOA guarantee.” This has nothing to do with your scope. It refers to the rifle’s mechanical accuracy potential. It means the manufacturer guarantees that, with specific high-quality ammunition and shot from a stable rest by a skilled shooter, the rifle can group all its shots within a 1-inch circle at 100 yards. In reality, many rifles can do better, but it’s a common benchmark for a precision rifle.
Practical Tips for Shooting with MOA
* Start with a Solid Zero: Always begin with a perfect 100-yard zero. This is your baseline for all further calculations.
* Use a Ballistic Calculator: Apps or charts can tell you exactly how many MOA to dial for any distance, considering your specific bullet, velocity, and conditions. This saves a lot of guesswork.
* Keep a Dope Book: “Dope” stands for Data On Previous Engagements. Write down the MOA come-ups you need for different ranges. This creates a personalized cheat sheet for your rifle and ammo.
* Practice Estimation: Try estimating wind holds using your reticle’s MOA markings. With practice, you’ll get faster at making off-the-cuff corrections.
Mastering MOA takes your shooting from hoping to knowing. It turns abstract concepts like bullet drop into a simple number of clicks. While the math might seem intimidating at first, a few range sessions with these steps will make it second nature. Remember, consistency is key—in your data, your ammo, and your shooting fundamentals.
Frequently Asked Questions (FAQ)
Is MOA better than MRAD?
No, it’s not better or worse. MOA is very intuitive for shooters who think in inches and yards. MRAD can be simpler for decimal-based math and metric distances. Choose what makes sense to you and stick with it for all your equipment.
How many clicks is 1 MOA on a scope?
It depends on your scope’s click value. On a 1/4 MOA scope, 4 clicks equal 1 MOA. On a 1/2 MOA scope, 2 clicks equal 1 MOA. Always check your scope’s manual to be certain of its specific click value.
Can I use an MOA scope with an MRAD reticle?
You can, but it’s not recommended for beginners. It forces you to constantly convert between two different angular units, which is a recipe for errors in the field. For simplicity and speed, match your turret units to your reticle units.
What does a 1/4 MOA click mean?
It means each audible and tactile “click” when you turn a turret will move your point of impact by 1/4 of a Minute of Angle. At 100 yards, that’s about 1/4 inch. At 200 yards, it’s about 1/2 inch, and so on.
How accurate is the “1 inch at 100 yards” rule?
It’s a very close approximation, but it’s not perfectly exact. The true trigonometric value is about 1.047 inches at 100 yards. For almost all practical shooting purposes, the 1-inch rule is perfectly fine and simplifies calculations tremendously. Only at extreme long range does the tiny difference start to matter.