I call serious BS on the '06 only leaving a dent in cardboard after a 9,000' free fall.
In a vacuum, any projectile fired vertically will return to its original location with exactly the same velocity as it was originally launched at.
In the atmosphere, terminal velocity depends solely on the drag coeficient of the falling body. Bullets have a very high sectional density and are quite aerodynamic, so they have the capability to pick up some pretty impressive velocities in a free fall.
If you dropped a bullet from high enough, it WILL go supersonic at some point. Hell, back in the early space program, they would have dudes jump out of high altitude balloons at 80,000 feet in pressure suits, and they would break the sound barrier during part of their fall. As they descended into denser atmosphere, they would slow back down though.
BTW, At sea level, acceleration due to gravity is 9.81 meters per second squared. 32.3 feet per second squared for those of you stuck on christian units.
-Spaceman