Re: Metric mil. application question
First of all (before anyone else jumps in and tears you a new one), mils are not metric. The only thing they share in common is that they are both decimal-based systems. Now that that's out of the way...
It's the last part of the calculation that's a pain. It's easy to take the size of the target, e.g. 18" = .5 yards, and multiple that times 1000 ( = 500 ). But if you ranged that object at 1.7 mils you have to divide 500 by 1.7. You can shuffle those things around (divide 1000/1.7, etc.) but there's no getting around having to do that. Maybe some guys are so good at math that it comes naturally.
Me, I try little tricks like figuring out how many times 17 goes into 100. My feeble mind can remember that 17 * 5 = 85 so that means that it's almost 6 times. Work those decimals back in there and you've got .6 * 500 = 300. Or how many times does 17 go into 50? Almost 3 because 17 * 3 = 51. So again I can get to 300. The actual distance is 294.12 yards...good enough.
You really only need to be precise once the drops start getting meaningful. For that, get a mil-dot master or (if you're brave enough) rely on some sort of electronic device.