This thread was started in 2011, but since I just purchased a BB gun. Ill put my 2 cents in. I live in the middle of a city, so shooting a rifle for any reason other than self defense would be a major crime for me, and going after a raccoon with a shovel isn't going to work. So after some thought, I purchased a electric fence and a Daisy BB gun as a added layer of defense for my coop. After firing both BB's and pellets I no longer consider the BB gun to be a toy. The model I purchased can be pumped ten times and maxes out at 880 Feet per second. That's over twice the speed of the cheap BB guns. It will send a pellet completely through a soup can so fast that the can doesn't even move. In fact, during target practice I thought I missed every shot until I went over to check the can. I never missed once, the can simply never moved. Its my opinion that my Daisy 880 can kill a dog, chicken, squirrel, or raccoon. HOWEVER, I seriously doubt that it would be a fast or humane death. The American FBI did a study which determined that death from firearms is the result of blood loss, not trauma. It stated that in the shootings that they reviewed, wide shallow wounds or thin deep wounds would have a high survival rate and a longer term of consciousness. While deep wide wounds tended to be quickly fatal. The BB or pellet is good enough to stop a raccoon attack in a way that would kill the animal. But the wound would not cause a humane or quick death.
The right to die advocacy groups have published a paper showing terminally ill patients how to build a suicide machine that would give them a fast painless death. If I ever had to put down an injured animal, I would employ that method. The method is gassing. Its a Party store tank of helium, a plastic hose, and a plastic bag. Helium is one of only a few gasses that does not cause a choking or feeling of suffocation. If you stepped into a room full of helium, you would never know it. You would simply black out. You would breath normally until you simply drop like a stone. This sounds better than drowning, of cutting the throat or stomping on a broomstick to break the neck.
(Don't confuse helium with the co2 technique snake enthusiasts use to gas mice. carbon dioxide is a far different gas than helium. it does cause the feeling of suffocation and the mice do panic. Unlike helium, carbon dioxide is a death very similar to drowning.)
Riki