I know that "water cannon" overstated the case a little ...
I have some water cannon envy. All I have is a Super-Soaker, and the animals where I live are quite entertained when I try to reason with them.
That is to say, they seem to be laughing as they vanish long before i can get all the way out the door.
I thought the Super-Soaker would solve my reluctance to use a slingshot - even with just a pine cone as ammo - on animals. I'll never know, unless an animal shows up who's as slow as I am!