Re: for a noob best to start with MOA or MIL
With regards to the metric system comment, perhaps it was in error. The basic premise for understanding a radian is the relationship that a radian is the angle subtended by an arc length that is equal to the radius. A millradian extends it to the angle subtended by an arc length that is 1/1000 of the radius.
This concept allows one to determine range in units of what is being ranged.
Borrowing the image of the MLR2 below from cstactical.
The target is 8 feet tall and is rougly 1.75 mils.
So the distance would be (8 / 1.75)*1000 = 4571 ft.
Then convert it into any unit your data card is in, for yards: 1523.
The calculation above is pretty close to the actual range:
http://www.cstactical.com/Magazine/SHOT-SHOW/SHOT-SHOW-BLOG-2011/Nightforce-New-MLR2-Reticle.html
Hypothetically, if we made an error in dope and wind call that was exactly a mil off we would have to dial in 1 mil of adjustment in elevation and windage. In a mil/mil scope, that's just 10 clicks the right direction. If it's a mil/moa scope, then it's remembering a mil is 3.375 moa and then dialing in 13.5 clicks, on a 1/4 MOA turret, of elevation and windage.
For me, being simple minded, I just prefer consistent units and counting using the decimal system.
Sorry if that was just rehashing rudimentary information for anybody.