Often at the range I have had to explain to people what Minute of Angle (MOA), and Milradians mean. Today I was reading about the Nemo .300 Win Mag ARs and I found they had a nice explaination of the two in their rifle’s manual.
Quoting from the Nemo manual:
Mils and MOA differ from an inch because they are angular, not linear, measurements. An inch equals an inch no matter how far away it is.
What is MOA? MOA stands for minute of angle. There are 360 degrees in a circle and each degree is divided into 60 minutes. If we round to the nearest 1⁄100 of an inch, at 100 yards 1 degree measures 62.83 inches. One MOA, 1⁄60 of that, measures 1.047 inches. While 1 MOA at 100 yards equals 1.047 inches, at 200 yards it equals 2.094 inches (2 x 1.047). To calculate MOA at any distance, multiply 1.047 by the distance in yards and divide by 100.
What is a MIL? MILS (milliradians) is another angular measurement. There are 6.2832 (π x 2) radians per circle. There are 1,000 mils per radian so, there are 6,283.2 mils in a circle. There are 21,600 MOA in a circle, so a little quick division determines there are 3.4377 MOA per mil. At 100 yards, 3.4377 MOA equals 3.599 inches (3.4377 x 1.047). Rounded up, one mil equals 3.6 inches at 100 yards. A mil is so large, it’s broken into tenths in order to make precise adjustments. If you have a riflescope with mil adjustments, each click equals 1⁄10 mil. A tenth of a mil equals .36 inch or .9144 centimeter at 100 yards. Since 1⁄10 of a mil is an angular measurement, it will be slightly larger at 100 meters than at 100 yards because 100 meters equals 109.361 yards. At 100 meters, 1⁄10 of a mil equals .9999 centimeter. Practically speaking, 1⁄10 of a mil equals 1 centimeter at 100 meters. Because mil, like MOA, is an angular measure, the length it represents increases with distance. For example, 1 mil at 100 yards equals 3.6 inches and 7.2 inches at 200 yards. To calculate how many inches are in a mil at any distance, multiply 3.6 times the distance in yards and divide by 100.
Their manual does an excellent job of summing up what the two are. Sometimes I have a hard time explaining this to new shooters.
Then question then arises, “Which is better?” Neither, they are two options with various pros and cons. If you shoot paper targets at known distances, MOA is usually preferred. You can measure or see how many inches of adjustment you need on paper, convert number of inches to minutes, then convert adjustment that to clicks. Mil adjustments are usually 1/10 mil per click, making the math similar to when you use SI units(metric system).
Both systems work well, the only main suggestion I have is don’t use a scope that mixes the two. It used to be common to have scopes with a Mildot reticle, and MOA turrets. This can make the math a pain.
If I am shooting at 565 yards, and I am using a MOA scope and I see I am impacting a foot low I know that.
1 foot = 12 inches.
1 MOA at 565 yards is about 5.6 inchs.
So 2 minutes of adjustment would be about 11.2 inchs, so I would want to come up about 2 and 1/4 MOA.
If I am using a Mildot reticle and a 1/10 mil turret, I can use my Mildot to measure the angular distance from my point of aim to my impact. So if I see its 1.2 mils low, I dial up 12 clicks.
But when I used a mixture of the two, I usually have to break out my calculator.
So once again I am shooting 565 yards, and I see I am impacting 1.5 mils low. I have to convert that mil measurement into MOA. So if I am in a hurry I would times 1.5 by 3.5(rounding) which is a little over 5 minutes. 5 and 1/4 MOA to be exact. Then I would dial that 5 1/4 MOA into the turrets of my scope. The math conversions can quickly get annoying. This is why I got rid of the Super Sniper 10x scope I had, and something I find irritating when I use my Leupold TS30-A2.
It doesn’t really matter if you use MOA or mils, but which ever you use, train to be competent and confident with them.