The whole hydrostatic shock thing is extremely misleading. The vast majority of this shock is created very shortly after the bullet enters the animal. The reality is that every animal experiences that shock. Watch the video of the barnes bullets ripping into the gelatin...
http://www.barnesbullets.com/videos/...V9_640x480.wmv
Is there any doubt that there is shock present? Hell no. Does it kill the animal? Hell no. It "temporarily" displaces tissue. What kills the animal is the massive trauma that the bullet causes. Without the trauma there is just a bunch of bruising that will hurt like the dickens. Maybe in a few hours or days that bruising would result in death but it would again be because the animal bleeds out.
I will take 2 exit holes every time. I have had 3 BT's fail to provide penetration for me. All were on deer. 2 out of a .257 Roberts and 1 from a .243 Win. Never again will I trust them. I may try the Bergers as they tend to open after being inside the animal a few inches.