Okay, deep breath. This is the chapter that scares people most, and it absolutely shouldn't. We're going to make this genuinely simple.
The problem these solve
When you shoot at something far away, the bullet drops due to gravity on its way there, and wind pushes it sideways. To hit the target, you have to aim a little high (to compensate for drop) and sometimes a little to the side (for wind).
Your scope lets you adjust for this — either by dialing the turrets or by holding using the reticle marks. But to do that, you need a unit to measure these adjustments. That's what mils and MOA are: units for measuring angles, which is how we measure aiming adjustments.
That's all they are. Units. Like inches or centimeters, but for angles.
Why angles?
Here's the elegant part. Because the target is far away, the adjustment you need is an angle, not a fixed distance. A small angle covers more actual distance the farther out you go. This is handy because the same angular adjustment works at any distance — you just need to know how much angle equals how much drop at each range, which your ballistic calculator tells you.
Don't worry if that doesn't fully click yet. It will once you're actually using it.
MOA (Minute of Angle)
MOA stands for "Minute of Angle." One MOA is a tiny angle that happens to equal almost exactly 1 inch at 100 yards. This makes it intuitive for people who think in inches and yards:
- 1 MOA ≈ 1 inch at 100 yards
- 1 MOA ≈ 2 inches at 200 yards
- 1 MOA ≈ 5 inches at 500 yards
- ...and so on (it grows proportionally with distance)
So if your bullet is hitting 5 inches low at 500 yards, that's about 1 MOA low, and you'd adjust 1 MOA up.
MOA scopes typically adjust in 1/4 MOA clicks (each click moves the point of aim 1/4 inch at 100 yards).
Mils (Milliradians)
A "mil" (milliradian) is another angular unit. It's a bit bigger than MOA: 1 mil equals about 3.6 inches at 100 yards. Mils are based on a different math system (it's a metric-flavored angular measure), and here's why a lot of people like them:
- 1 mil = 3.6 inches at 100 yards
- 1 mil = 7.2 inches at 200 yards
- 1 mil = 36 inches (about 1 yard) at 1,000 yards
Mil scopes typically adjust in 0.1 mil clicks. The mil system is clean and easy to do quick math with once you're used to it, and crucially, it has become the dominant standard in this sport. Most competitors use mils, most reticles and instructional content are in mils, and you'll fit in more easily with mils.
Which should you choose?
Choose mils. As mentioned in the scope chapter, mils have become the standard in precision rifle. The advantages:
- Most of the community uses mils, so communication is easier ("come up 0.3 mils" is common range language)
- Most modern precision reticles and scopes are designed around mils
- Instructional content, DOPE charts, and apps default to mils
- The math is clean once you learn it
MOA isn't wrong — it's perfectly functional and some great shooters use it. But for a beginner joining this sport today, mils is the path of least resistance and best community fit.
The one rule you must follow
Whatever you choose, make sure your reticle and your turrets use the SAME unit. A mil reticle with mil turrets ("mil/mil") or an MOA reticle with MOA turrets. Never mix them — a mil reticle with MOA turrets is a recipe for constant confusion and errors. When buying your scope, confirm it's matched. For beginners: get mil/mil and you're set.
Do I have to do math in my head?
Not really, especially at first. Here's the reassuring reality: your ballistic app or Kestrel does the calculating. You tell it the distance, and it tells you "dial 2.3 mils up." You dial 2.3 mils. Done. The deep understanding of why comes with time, but you can start shooting accurately by simply trusting your ballistic calculator and dialing what it says.
The reticle math (holding off using the marks instead of dialing) takes more practice, but you'll get there gradually. For your first matches, you can dial most shots and keep it simple.
See? Not so scary. Mils and MOA are just units, your calculator does the heavy lifting, and you pick mils to fit in with the sport. Moving on.