For the discussion about velocity/mass/etc, the new polymer bullets that, according to the manufacturer, create huge wound tunnels due to the velocity of the bullet, may change the way we all think about caliber.
https://www.inceptorammo.com/inceptor-p ... d-defense/
Upon entering soft tissue, the specially designed grooves in the nose harness the soft tissue and constrict, pressurize and eject it at 1.5 to 2 times the directional speed of the bullet. This is the well-known Venturi Effect. As the bullet penetrates, it tumbles in a controlled, predictable fashion that delivers consistent terminal performance that equals or exceeds conventional hollow-point designs without over penetrating.