The Minute of Angle unit is useful to shooters not only to hit that far away target, applying Long Range Shooting Technique but also when you are zeroing in a new scope, or you need to range a target at an unknown distance.
My old man always told me:
“If you can hit a salad plate (6 inches to 8.5 inches) at 100 yards you can hunt whatever you want with your rifle.”
Because the kill zone on most game animals is larger than a 6” plates, that rule usually proved to be right for years on my hunting grounds.
However, in my hunting areas deer and hogs often appeared at distances shorter than 100 yards, and practically it was a hunt in terrains that didn’t allow for more than 50-yard shots
Unlike these shots with the average targets distanced at 75 yards, many hunters live in regions that necessitate long shots and basic ballistics knowledge.
One of the most often heard terms in the long-range community is “One arc minute”, also referred to as Minute of Angle or for short MOA.
The MOA is the standard unit of angular measurement used to determine a rifle’s accuracy, scope adjustments and types of scope reticle. The MOA is used for group size measurement and it is basically an ever-widening angle, where the size of an MOA widens proportionally to the rate of distance increment.
How to Understand Minute of Angle (MOA) – Long Range Shooting Technique
|At 200 yards||1 Minute of Angle =||2 inches|
|At 300 yards||1 Minute of Angle =||3 inches|
|At 400 yards||1 Minute of Angle =||4 inches|
The MOA is equal to 1/60 of 1 degree that amounts 1.0471996” at 100 yards, but it is more convenient to round the figures off, so in daily life, we usually express 1 MOA as 1 inch per 100 yards.
Obviously, for extremely long shots you shouldn’t ignore the .0471996 decimals, as these almost 0.5 inches at 1,000 yards has a significant impact for precision shooters.
Long range shooters use MOA value to present their need for accuracy, and if you start shooting longer ranges, you might want to use the 1.047-inch because at longer ranges that small rounding to 1 inch might make a difference.
However, for obvious practical reasons close range hunters will stick with a simple, useful, rounded-down inch because at 200 yards with a rifle/ammo combo of 5 MOA, the difference is probably lost in the noise.
As earlier mentioned an MOA spreads out about 1″ per 100 yards, so our nominal inch at 100 yards is a half-inch at 50 yards, 1 MOA at 200 yards is 2″ and 1 MOA at 300 yards is 3″
Because 1 MOA is equal 1” PER 100 Yards:
|100 yds.||200 yds.||300 yds.||400 yds.||500 yds.||600 yds.||700 yds.||800 yds.|
How to Set the Minute of Angle?
When your rifle consistently shoots within 1-inch circle at 100 yards distance, measured from center to center of the points of impact, we are saying you are shooting 1 MOA groups.
For situations when we need to gauge a rifle’s accuracy or sight in a rifle speaking in MOA is a precise statement.
For example, if you claim your rifle shot a 6-inch group; in case your target was at 400 yards, that’s impressive, but if your target was at 40 meters, you perform poorly. On the other hand, if you state your rifle makes 1MOA groups, in that case, we would know there is a superior accuracy.
The trajectory of a bullet is never a straight line due to the forces such as air resistance, gravity and wind that influenced its travel. Considering that, we usually had a difference between our Point of Aim (POA) and our Point of Impact (POI) measured as an angle and expressed using MOA term.
The process of sighting in a rifle refers to matching the POI exactly at the same place as your POA, and for this purpose, we need some MOA understanding.
Because 1 MOA = 1” PER 100 Yards:
|At 100 yards||3 MOA =||3”|
|At 200 yards||3 MOA =||6”|
|At 300 yards||3 MOA =||9”|
|At 400 yards||3 MOA =||12”|
|At 1200 yards||3 MOA =||36”|
The concept of a minute of angle is simple but to apply it in practice we need adjusting the rifle scope changing the angle of your barrel to the target with the help of knobs for windage and elevation.
A typical hunting scope features adjustment in ¼ MOA per click, meaning that each click or turn or the Turret represents .25 Minutes of Angle or 1/4 of 1 Minute of Angle. In the other word, if you need to adjust 1 MOA, you will need to turn the dial four times that means that 4 clicks would adjust 1 MOA.
If you are purchasing a high-power scope for benchrest, target or varmint applications, it is likely to have fine adjustment dials marked at minor intervals of 1/8 MOA.
Whereas some scopes knobs are featuring coarser adjustment intervals set at ½ MOA or 1 MOA, European rifle scopes usually feature MOA increments attuned to the metric system.
One more note you should know is based on the quality of your scope. A $2,000 Zeiss will give you a very accurate one fourth of MOA adjustment per click, whereas a $50 Chinese glass probably won’t.
Anyway, we will be keep on ¼ MOA adjustment as the major calibration for the most of retail scopes. So, for example, let’s say that you have a rifle scope that moves reticle .25 MOA per click and you are zeroing in on a target 100 yards away.
So if your shot is grouping 2 inches low, that would require you to adjust 2 MOA up and you will do this by moving up the elevation knob 8 clicks in order to move up those 2 inches.
In case you have the same situation, but at 200 yards, that would require you to adjust just 1 Minute of Angle, that is you would have to make 4 clicks in order to move 1 Minute of Angle at 200 yards, which would be 2 inches.
Here’s one bit more detailed description: say we are zeroing in at a target 800 yards away and your shots are 16″ to the left and 8 inches low.
How many MOA do you need to make corrections and in which direction?
You have to move 2 MOA to the right making 2 clicks and 1 click upward, because 1 MOA at 800 yards is 8″.
Understanding MOA comes extremely useful when you want to sight in your rifle because mastering this skill would prevent you from wasting of a lot of ammo and wasting of an accurate firearm, not to speak about lost time and hard-earned money.
Now that you understand Minutes of Angle and how it is converted to inches will help you adjust your scope to hit your target at any distance.
With more than 50 years experience in the field and the testing lab, author L.P. Brezny is one of today’s most recognized shotgun experts and authors. He is a contributor to dozens of firearms publications, such as Wildfowl, Shotgun Sports, and Varmint Hunters, and he is a regular columnist in the Gun Digest annual as well as AmmoLand News.