MOA vs MIL, and How to Zero a Rifle Scope

If you have looked at riflescopes, you will have met two sets of numbers on the turrets and reticles: MOA and MIL. They can seem like rival languages, but they describe the same thing — small changes in angle — and once you understand what a click actually does, zeroing a scope becomes a calm, methodical routine rather than guesswork. This guide explains both systems in plain terms and walks through a basic zeroing procedure.

Why sights measure angles, not inches

A scope does not move your point of impact by a fixed number of inches. When you turn an elevation or windage turret, you tilt the line of aim by a tiny angle relative to the bore. Because the bullet travels farther before it crosses that adjusted line, the same angular change produces a larger shift on the target the farther out you shoot.

This is the single most important idea to hold onto: an angular measurement stays constant, but the distance it covers on paper grows with range. One MOA is a different size at different distances — around 8 inches at 800 yards is still just 1 MOA. Both MOA and MIL are angular, which is why a single turret setting works at every range, and why holdovers in a reticle behave the same way regardless of distance, as long as you think in angle rather than inches.

Minute of angle (MOA)

A minute of angle is a unit of angle. A full circle is 360 degrees, each degree divides into 60 minutes, so 1 MOA is one-sixtieth of a degree. At 100 yards, 1 MOA covers very close to 1 inch. The common shorthand is “1 MOA is about 1 inch at 100 yards,” though the true figure is 1.047 inches — a difference too small to matter in most shooting.

Because MOA is angular, its size on the target scales with range: roughly 1 inch at 100 yards, 2 inches at 200, 3 inches at 300, and 5 inches at 500. At short and mid range the 1-inch approximation is perfectly workable. By 1,000 yards the rounding adds up to about half an inch per MOA, so for long range it is worth working from 1.047 inches, or letting a ballistic app handle the arithmetic.

The milliradian (MIL or MRAD)

A radian is the angle you get when an arc equal to the circle’s radius is laid along its edge. A milliradian is one-thousandth of a radian. Thanks to that one-in-a-thousand relationship, a mil covers 1 unit of length at 1,000 units of distance — for example, 1 metre at 1,000 metres, which simplifies neatly to 10 cm at 100 metres. In customary units, 1 mil works out to 3.6 inches at 100 yards.

The tidy metric maths is the mil’s headline feature. Since one click is usually a tenth of a mil, 0.1 mil equals exactly 1 cm at 100 metres — which makes mental corrections simple when your range is measured in metres. The terms “MIL,” “mil” and “MRAD” all refer to the milliradian here.

Turret clicks, and matching reticle to turret

Turrets do not move continuously; they move in discrete clicks, each a fixed fraction of MOA or mil. The most common values are ¼ MOA and 0.1 mil, though ½ MOA and 1 MOA turrets exist too. A quarter-MOA click is about 0.26 inch at 100 yards; a 0.1-mil click is 0.36 inch at 100 yards, or exactly 1 cm at 100 metres.

The practical point is simple: match your reticle units to your turret units. A mil reticle paired with mil turrets — or MOA with MOA — lets you read a correction straight off the reticle and dial the identical number, with no conversion. A MOA turret behind a MIL reticle just adds an extra sum to every shot. If your reticle is in mils, choose mil turrets; if it is in MOA, choose MOA turrets. The goal is to see a miss in the reticle and dial the same number, with no maths under pressure.

What “zero” means

Zeroing is adjusting your sight so that your point of aim — where the sight says you are pointing — matches your point of impact, where the bullet actually lands, at a chosen distance. A rifle is “zeroed at” the distance where those two points coincide.

Because the bullet leaves the bore below the line of sight, rises across it, then falls back through it, the zero distance shapes your usable trajectory. Common choices include 25, 50, 100 and 200 yards. A 25- or 50-yard zero is handy for getting “on paper” before confirming farther out; a 100-yard zero keeps corrections simple with most common calibres; and a 50/200-yard “combat” zero is popular in law enforcement for minimal vertical deviation from 0 to 300 yards. There is no single correct answer — it depends on cartridge, typical distance and role.

A simple zeroing procedure

The following is a basic process for zeroing at 100 yards. A zero is only as good as the consistency of the shots that produced it, so apply steady position, breathing and trigger control throughout.

1. Set up a stable platform. Use a bench, bipod or sandbags so the rifle, not your hold, defines where the shots land.
2. Confirm your click value. Check the turret cap or manual for whether each click is ¼ MOA, ½ MOA or 0.1 mil.
3. Fire a group. Fire a tight group of three to five rounds at a single aiming point, then use the centre of the group — not any single shot — as your point of impact.
4. Measure the offset. Measure how far the group’s centre sits from your point of aim, both vertically and horizontally.
5. Calculate the clicks. Divide the offset by the value of one click at your zero distance. A group 3 inches left on a ¼-MOA scope needs 12 clicks right (3 ÷ 0.25). If you are 2 mils left on a 0.1-mil scope, that is 20 clicks right (2.0 ÷ 0.1).
6. Adjust. Dial the calculated clicks in the correct direction; turrets are marked UP/DOWN and L/R, and many move the point of impact in the labelled direction — confirm with your manual.
7. Confirm. Fire a fresh group and check the centre now sits on your point of aim. Repeat until the two match, then, if you wish, reset the turret indices to zero so future dialling starts from your zero.

One thing to watch: click values are referenced to 100 yards or metres. If you zero at 50 yards, each ¼-MOA click moves the impact only about half as far on paper, so you will need roughly twice as many clicks for the same measured offset. The closer the target, the more clicks it takes to move the group a given amount.

MOA or MIL — which should you choose?

This is the most argued and least important question in optics. Both systems are angular, both are precise, and neither is inherently more accurate. A ¼-MOA click is slightly finer than a 0.1-mil click, but the difference is negligible for most shooting. The two are directly convertible: 1 mil equals 3.438 MOA — multiply mils by 3.438 to get MOA, or divide to go back.

What actually matters is consistency. Keep the same unit on your reticle and turrets so you never convert mid-string, and stick with one system long enough to think in it fluently. Mil tends to suit those who work in metric or alongside others using mils; MOA feels natural to shooters who think in inches at 100-yard steps. Either is a sound choice — the right answer to “MOA or MIL?” is “the one you will use consistently.”

If you are putting together a new optic setup, you are welcome to browse our riflescopes, along with scope mounts and red dot sight mounts. If you would rather talk it through in person, our team in Varna is glad to help you work out which system and setup suits how you shoot.