Quote:
I fully realize that drag increases with the square of the velocity, but 100 fps just cannot be so.

As I recall this applies only below the speed of sound. When you break that sonic barrier drag increases dramatically. As the shot exits the muzzle it does so as a mass acting much like a single projectile, but very quickly begins to separate into individual pellets, all occurring at a much less distance than that 9'.The Ballistic Coefficient of an individual pellet is far less than that of the compact mass at exit. These two factors of the drag swapping from a single mass to individual pellets, plus the vastly greater drag above the speed of sound" Very Easily" account for far more loss of velocity over those 9' than 14FPS.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra