[Vinnie]

I've been to other web site where there have been long discussions concerning viscous dog attacks.

From first hand accounts by LEOs and others it seems a determined dog, esp. a pit bull is very hard to put down.
Pit bulls in particular seem to be impervious to pain. They must be physically incapacitated.
Even shot through both shoulders doesn't stop them from trying to get you.
A pit bull's flat head may cause a bullet to merely ricochet off in a head on shot.

[csvset]

A neighbor and I had to shoot a Pit Bull that was attacking another neighbor's dog. I shot the PB three times with a .357 , ( 158 gr ), in the upper back.

I was limited to that area due to the way the dog was positioned and safety factors. That caused the dog to drop the other dog , however, he was mobile. The other neighbor put either 6 or 7 9mm rounds into him, through his ribcage. That finally dropped him. I suspect his rounds probably hit his lungs. Your mileage may vary.