One of the most common questions new shooters ask is Mils or MOA when setting up their new long-range rifle. Today I want to take a more in-depth review of both Mils and MOA to help you make that decision for yourself. There is a lot of bad information and misconceptions around Mils and MOA as they relate to shooting. I will cover those below as well.
MILS ARE METRIC AND MOA IS IMPERIAL
Possibly one of the biggest misconceptions in the long-range shooting community is that Mils or MOA only correspond to a set measurement system. This actually has zero truth behind it. Both Mils and MOA are angular measurements. Angular measurements work with any system of measurement in existence.
One mil is 1/1000 of the unit of measurement (feet, inches, centimeters, meters, miles, ect) you choose to use. Therefore .1 mil is 1/10,000 of the unit of measurement (feet, inches, centimeters, meters, miles, ect) you choose to use. So 1 mil at 1,000 meters is 1 meter and 1 mil at 1,000 yards is 1 yard. .1 mil is 1 centimeter at 100 meters and .36 inches at 100 yards.
MOA (Minute of angle)
One MOA is 1/60th of a degree. At 100 Yards 1 MOA equals 1.047 inches and at 1000 yards one MOA equals 10.47 inches. At 100 meters 1 MOA equals 2.908 centimeters and therefore at 1000 meters 1 MOA equals 29.08 centimeters.
MOA IS A MORE ACCURATE ADJUSTMENT SYSTEM
The answer to this is not a simple yes or no. On paper MOA adjusts in smaller values and because of that it is seen as more precise by some but is the difference an advantage or is it a negligible difference? You can decide below.
Size of adjustments
Mil scopes are most commonly found with 1/10 mil turrets. This means that every “click” the turret is moves corresponds to a 1/10 mil adjustment to your point of aim. MOA scopes are most commonly found with 1/4 MOA turrets. Just like the Mil turrets 1/4 MOA turrets adjust your point of aim by 1/4 and MOA with every “click”. Some MOA turrets are set to 1/8 MOA values and are not as common.
1/10 Mil Vs. 1/4 MOA
Starting at 100 yards 1 Mil equals 3.6 inches and 1 MOA equals 1.047 inches. Therefore 1/10 of a mil equals .36 inches and 1/4 of an MOA equals .26175 inches at 100 yards. The difference of the adjustments is .09825 inches.
At 1000 yards 1/10 of a Mil equals 3.6 inches and 1/4 MOA equals 2.6175 inches. The difference between the two systems is .9825 inches. It is possible that the top 1% of shooters would actually be able to tell such a small difference in adjustments, however when we take into account environmental factors like wind as well as bc errors, shooter error, and rifle capability is the average shooter able to discern the minute difference or “edge” that MOA presents with a smaller adjustment value?
Number of clicks
Using data from my .308 and Applied Ballistics mobile app I have 2 photos below. Both account for the same distance of 1000 yards with a 10 MPH constant wind at 90°. One accounts for adjustments in 1/10 Mil and the other 1/4 MOA.
The results above show an additional 40 clicks are needed to get the same firing solution while using MOA over Mils. Is the extra time spent dialing in your adjustments worth the smaller value? It depends on the style of shooting and personal preference and is for you to decide.
1 MOA IS CLOSE ENOUGH TO 1 INCH AT 100 YARDS
As we discussed above 1 MOA at 100 yards is 1.047 inches. A common trend is to round 1.047 down to 1 inch to make math easier. While this might have a minimal effect at closer ranges it will cause misses at longer ranges.
Using the example above at 1000 yards the .308 bullet drops 36.3 mils or 380.061 inches. When 1 MOA is rounded down to 1 inch instead of 1.047 inches the drop changes to 363.0 inches. This small and seemingly harmless error in math actually equates to 17.061 inches or 1.630 MOA that your adjustments are off.
WHICH IS THE BETTER SYSTEM?
Neither. It is a personal choice. If you shoot bench rest and the targets are in MOA then MOA makes more sense. If all your friends shoot Mils getting data for corrections will be easier if you to shoot Mils. I use Mils because it is what I was taught in the Military but instead of meters I range my targets in yards. No matter which system you choose make sure that you are educated and comfortable with making adjustments.