The reason a bullet doesn't plow over a deer is the fact that that energy is transfered over time and in all directions. Not instantly and not in a single foward direction.

It's real easy to see how the two kill. shoot two milk jugs filled with water or shoot two water mellons.

Hydrostatic shock is a real phenomenon that happens any time a fast moving object strikes something made up of mostly water such as an animals body. If it didn't happen the bullet would simply punch a hole the same size of itself and do very little damage to the internal organs of the animal.