Horizontal distance in scope of Battlefield 3?

Solution 1:

I don't think that there are a reliable ratio.. cause there are a LOT factors you have to consider..

for example:

1. the distance between you and the enemy
2. the difference in height. is your position "over" the enemy? is he on a highground?
3. the enemy movement. as you mentioned: running with(out) sprint, etc
4. your stand: stay, crouch, prone
5. enemy stand
6. the bullet drop of the weapon
7. the scope you attached to the weapon (ACOG, 8x, 12x, ...)

i think the only reliable is training. the more you play the more you get used to all of the aspects you have to consider.

EDIT: This video shows a few tips, tricks and hints. I think this is a good video for the basics:

(sorry for my english.. i'm not a native speaker)