i'm no expert on ballistics but for your second question, it is possible to range a target with your scope. I learned on an 4x ACOG with a long vertical crosshair and a number of smaller horizontal crosshairs. the horizontal crosshairs represent 19 inches at a given range, the width of an average man's shoulders. with something of a known or approximated width in your scope, you simply put whatever crosshair matches up with the width of 19 inches worth of target, and that's your elevation adjustment.
your optic may have a similar set-up, measurements are likely different but the concept is the same. it may help to write things down, such as what mrkers within your scope to use at what ranges.
now I have a question. are "mil dots" what i described above? personally I've never heard anyone refer to "mil dots" outside of forums.