I recently discovered and downloaded a free program called Hawke Ballistic Reticle Calculator and started punching in data for my X28 airsoft rifle. Now I realize that a ballistic calculator is not really necessary for airsoft but it might be usefull to know exactly where each mil dot hits for longer range shots (200+ feet) or if nothing else its something fun to mess around with.
Basicly the program predicts the point of impact (and other things like velocity at different points etc) based on a number of given variables. It can also specificly tell you where each mil dot on a scope will hit relative to the range of the zero. The tricky part however is that the program was not designed for airsoft bb's or the effect of hop up. As far as I can tell, the best way to measure the ballistic coefficient is to use "bullet" (bb) drop rather than fps loss because this way the equation includes the effect of the hop up which is basicly changing the ballistic properties of the bb in flight. I also used this meathod because the program has a minimum value that it will take for calculating the ballistic coefficient (using velocity drop puts it below the minimum for me). different hop up "strengths" will change the entire equation therefor and because of this you will need to make multiple graphs for the different "strengths" as each "strength" seems to be slightly different in how it affects the equation. Doing this however will expand your range in between your minimum and maximum distances though also which could be considered a good thing even though it is on multiple graphs now.
Anyway I have only had this program for a few days and barely know how to work it myself. If anyone has any thoughts about it in general or if this is just a bad idea trying to apply to airsoft in general I'd be interested in hearing your oppinion. Or try out the program for yourself.