I need to find a recent study that was done about different bullets and stopping attacks, basically it said with the advancement in bullets in recent years is not more about the size of the bullet but the ability of multiple hits rapidly. The study showed hat one stop hits were pretty rare in all the cases they looked at. I was the multiple hits on aren't that was stopping attacks. They concluded a smaller cal like the 9mm where you have a good weight and velocity that the recoil is manageable enough for quick well placed shots.