[HiTech RedNeck]

shot the dog with what, BBs?

[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.