If we assume that rotational velocity (spin) decreases at the same rate as flight velocity the bullet won't be spinning much when it contacts game , depending on range of course. And I'll bet it slows to nothing when it expands...a bullet is not a good flywheel. It's mass is not far from the center.
See if you can find any ballistic gel tests showing spiral lines in the cavity.
Checkout the multiple rotations the bullet makes as it passes through a 16" length of ballistic gelletin.
