
It's a program that allow you to use your computer as a chrono. You place your computer excactly between your target and your muzzle, start the program, and fire. The program calculates your projectile speed at the muzzle from the sound. i havent personally tried this yet, but i have of several peple that have had good experience with this.
Enjoy

http://talonairgun.com/softchrono/SoftChrono_beta1.ZIP