I can't help but wonder if it's because the Barnes maintains its weight and velocity better as it travels through the medium,maintains a consistent expanded frontal area,while conventional bullets lose weight and momentum as they are torn apart.
This would theoretically have the opposite effect to what is observed- the mono would travel farther forward while maintaining rotational speed, while the C&C would keep spinning but slow its forward motion, showing an increase in twist as it progresses through the media.
Something else must be at play here. Perhaps the propeller effect John mentioned.
