What is referred to as hydrostatic shock is basically the transference of energy, outward from the bullet, through the cells. When you skin a deer, you will see the effects. You may have a 1.2 inch wound channel. but you have a couple inches of bloodshot meat all around this wound channel. Basically, that outward force has destroyed the surrounding cells. This doesn't knock and animal down, unless the CNS is effected. But all trauma is good when you are trying to kill an animal quickly.

A surgeon will tell you, if they get a GSW victim in, the first thing they want to know is whether it was a HP rifle or a slower velocity handgun. The difference in viable tissue will be huge.