It's pretty hard to keep an outdoor cat controlled. I can vouch, because I've been through three black cats in the past six months. The first, He Who Cannot Be Named, just disappeared one day. He wasn't very prone to wandering off, so I don't know what happened to him. I'm thinking a hawk may have gotten him or something. The second, Shadow, got run over in the highway. I hadn't even known he was wandering that far until I came home from work one day and saw my lil' buddy splattered all over.
So the third, Thirteen, is turning out to be a house cat. I didn't want a house cat, because part of the reason for getting one was rodent control. I live way out in the country, and when I got He Who Cannot Be Named, he was a prodigious rat-killer... it was amazing. But, after losing two in quick succession, I can't really stand to gamble with 'em anymore, so Thirteen stays inside and gets spoiled rotten.
I'd hate for any of my cats to mess with anyone's bird feeder or their garden or anything, but if they shot
them over that, I'm afraid we'd have a little violence between us. Shooting feral cats is one thing, but gunning down people's pets... nope. Turn a hose on them or something if you must, but killing pets isn't admissible.