Yeah, I won't lie and say I killed it with the first pellet (.22 cal), even though I did hit it in the head. Their brains are about the size of a pecan, so hitting that through all the fur and face isn't easy, especially since I was way too close for the scope that was mounted on the rifle.
He was definitely in a fighting mood, and my IDIOT dog was certainly willing to give it a go. First time I've been proud of that little son of a bitch. He shook free twice and went right back into the fight. Luckily he didn't get hurt at all. Must be because he needs a damn haircut worse than I do.
Finally, after I'd knocked him down to the floor a couple times, he turned his head away for just long enough that I got a shot at the brain stem. Point blank with that pellet might have killed me too.
In that situation I think that I would have used a spear... mainly because I don't have a pellet gun.