If you are in an area where you can legally shoot, then I would go to a gunshop and ask for some 38special birdshot. It won't be as noisy as 357 ammo and will take down a cat at 15-20 ft without going completely thru a household wall....It will still break windows (if you hit them), make some noise and you will have to watch your backstop but any stray pellets will only travel a few hundred feet, versus almost a mile for your 357 slugs...