Re: MIL or MOA
The good thing about moa is that for group size at 100 yards 1moa is 1", at 200 yards, 1moa is 2" on out to 1000 yards 1moa is 10". Also, with a 308, round ball,
at 10mph crosswind and 100 yards crosswind correction is 1moa, at 10mph crosswind and 200 yards crosswind correction is 2moa
...
at 10mph crosswind and 1000 yards crosswind correction is 10moa etc
Unfortunately, 1moa at 100 yards isn't EXACTLY 1", it is like 1.05" a 5% error. USO has IPHY which IS exactly 1" per hundred yards. Except for DOPE and BOX test this 5% error isn't enough to worry about because 1moa group size at 1000 yards the difference is between 10 1/2"(true moa) and 10"(rounded moa).
The good thing about mils is most of the tactical shooters went this way and if you go to the tactical matches most, not all though, will have mil based scopes. 1/10th mil at 100 meters is 1cm, 1/10th mil at 200 meters is 2cm... 1/10th mil at 1000 meters is 10cm. Unfortunately most shooting courses (not all) are in yards, not meters.
Bottom line, get what your buddies have or your instructor wants you to get or what you are familiar with. If you don't know any of that, get mils because it is the up and coming thing. It's what the military uses and more tactical guys use it, it seems.