Does greater centripetal force reduce over penetration?
I think just the opposite. Bullets are designed to be used at certain 'twists' to be adequately stable in flight and have a minimum of precession. This is all based on certain altitude conditions or in reality, the density altitude. The higher the density altitude, the less spin it takes to stabilize because the air is thinner and has less effect on the bullet.
The same thing has got to be true when a bullet enters a much denser medium (tissue). It has got to be spinning to remain stable and maintain a straight path. The more it is spinning, the better chance it has of maintaining straight path.
As far as mono bullets expanding, I wouldn't bet my life on the small ones expanding every time.
