Don't know if yall have tried this yet. I don't know if I would pay the money for it, but somebody gave it to me for free and it is a great tool when you are bored between trips to the range. Has helped me out immensely with my range estimation.
They have a demo you can try...make sure to look it over
I'm a newby to the whole long range shooting though, so a vet might not get the same use out of it as I do.