I think I pretty much understand the twist/bullet lenght/stabilization thing. But I'm still interested in resolving the different view points expressed by UncleNorby and Articap.

If a bullet is shot from a barrel that has a 1:48 twist, is it possible for it to increase its rate of rotation after it leaves the barrel? That just doesn't seem possible. It seems it would rotate once for every 48 inches of travel. The issue is number of rotations per unit of distance vs. number of rotation per unit of time. Actually, rotation must slow down over both time and distance due to air friction.

Clearly, a faster bullet will have a higher RPM (time). But how can shooting a bullet faster cause the rotation to exceed the twist of the rifling (i.e. one rotation in 48 inches)?

(EDIT: Bronko got his answer in before this hit the screen. I agree.)