From the M4C link
"Holding at the top of a 3" circle will place the round in the lower 1/3 of the circle at 3 yards, and in the upper 1/3 at 70 yards.
Holding in the upper 1/3 of the 3" circle (1 inch high) will place shots within the 3" circle from 30 yards to around 200 yards (though most shooter/weapon/ammo combinations will not be able to maintain that level of precision past 75 yards or so). "
Doesn't get any simpler.
