Affect of rotational velocity on bullet performance

[Jordan Smith]

I also agree that higher rotation rates/inertia will cause more dramatic bullet expansion. Great that you have some evidence to back that up. I'll always remember my dynamics professor in college and his story about how to convince people that rotational inertia is real... Whenever he had a student that didn't understand, he told them to go jack up the rear wheels of their car, get them spinning to about 50mph, and then grab onto one of the wheels with both arms as hard as they could. Don't think anybody was dumb enough to try but it got the point across.

That sounds like an amusing experiment to watch!

Another way that I like to explain it to people, is that when we were kids we had tire swings mounted in the playground. A tire was suspended on the flat, with 3 chains around the circumference of the tire all converging to one mounting point up on the cross bar. One of us would sit in the tire, a lot like sitting on a tire tube on the water or sledding hill, and somebody would wind him up tight and let go. We'd play a game seeing who could hang on the longest before being thrown out of the tire and onto the gravel. The faster the tire spun, the harder it was to hang on. Similarly, the faster the bullet spins, the harder it is for it to hold together.