Someone please enlighten me as to the meaning of ballistic coefficient.  I think it has something to do with a bullets ability to retain velocity and keep its ballitic course.  I heard the term used in reference to bullets decelerating from supersonic to subsonic velocities at specific ranges, which causes the bullet to destabilize.  A more scientific explaination would be greatly appreciated.  Here's a good opportunity to show off your wits gentlemen, let my enlightenment begin.

The ballistic coefficient is a measurement of how well a projectile flys in the air. It relates the drag deceleration of a projectile to the drag deceleration of a standard bullet.

The higher the ballistic coefficient, the better the bullet performs in air.
(1) C = SD/i = w/id2


C = ballistic coefficient
w = weight of bullet, lbs.
i = form factor            
SD = secetional density
d = diameter of the bullet, in.