I was going to email this question to Michael Eichele since I'm using the ballistics program he gave me, but I thought I'd throw this out to anyone. How do you come up with the ballistic decay of a particular bullet? Why is it included in some programs? I'm assuming BC is measured right out if the barrel and two different bullets having the same BC might have a different BC decay rates which would result in different trajectories downrange. Am I on the right path here? Are decay rates of different bullets published anywhere?