Quote Originally Posted by hafejd30
Yup you got'er now.

on to my next question, what do you do if its gusting? its not 20mph all the time. sometimes 10 then hitting 20... sounds like half luck to me/guessing...

Pray ;D

The variables change all the time. Some shoot between gusts. Depending on the terrain of the area you could experience winds in both direction. Only thing that corrects past the data on a piece of paper is experience.
This is where experience and luck come into play. Get out on the range and practice practice practice.

As for having a ballistics program, you should know how to do tings without them. The day you are going to need to dope in the field, you batteries are going to die, or your smart phone is going to take a crap.