Angles and adjustments

What is the difference between minute of angle (MOA) and milliradian (Mil) in relationship to scope adjustment?

The old ‘one click equals a ¼in movement at 100 yards’ is so imprinted in my mind that it’s hard to grasp another system.

Basically, these are angular units of measurement that refer to changing angles or degrees of adjustment, as in a compass. One minute of angle (or MOA) is actually 1/60th of 1 degree. In linear terms, this means 1 MOA equates to 1in at 100 yards. The true value is really 1.047in at 100 yards, but the reality is we all use an inch. It’s easier. So, at 200 yards, it would be 2in, at 300 yards it is 3in and so on for each click of the scope.

A milliradian (or Mil) is defined as one-thousandth of a radian. In linear terms, 1 Mil is 3.6in at 100 yards (though the true value is 3.438in). So, if your scope has ¼ MOA adjustments, then it means a 0.25in movement of the reticule at 100 yards, or 1/10th Mil moves it 0.36 of an inch. BP