[zoomie]

You can get adjustments in mils, also. They're used the exact same, just different quantities.

Originally Posted by http://demigodllc.com/articles/practical-long-range-rifle-shooting-optics/?p=2

Instead of measuring hold-over in terms of linear distance (inches or cm), it would be helpful to translate those linear distances into units of angular measure. The concept of angular measure is that an angle of 1 degree demarcates 1.7 yards at 100 yards, or 3.5 yards at 200 yards. Everyone with a basic understanding of geometry should understand how angles work.

There are two units of angular measurement commonly used in rifle scopes. The first is the "minute of angle." Dividing a circle into 360 degrees, then each degree contains 60 minutes. One MOA demarcates 1.0472" per 100 yards of distance.

The second is the "mil". One mil is one part transverse per 1000 parts distance. In units we understand, 1 mil is 3.6" per 100 yards (ie, 100 yards is 3600", one thousandth of which is 3.6"). Consequently it's also 1 yard at 1000 yards. Alternatively, in metric, 1 mil is 10cm per 100 meters, or 1m at 1000 meters.

Originally Posted by http://demigodllc.com/articles/practical-long-range-rifle-shooting-optics/?p=6

In principle, either system can be used. If you're thinking about or communicating elevation values (for example looking at data and then dialing or holding off), a typical elevation value in MOA for 308 looks like "11.25" which is four digits, but the same mil-based would be just "3.2" or two digits. (In fact you can go out to over 1000 yards before needing more than two digits of elevation in mils.) This is less information to process.