while it is possible to adjust a paintball gun where it shoots much faster than 300 fps, i doubt very much that there is any spot you could hit a healthy cat that would kill it.
if you get a solid shot, the ball breaks like a water balloon so it doesn't hurt much at all. if you get a glancing blow so the ball doesn't break, it will leave a nice welt, but it's certainly not life threatening, even to a cat.
if you get a solid shot, the ball breaks like a water balloon so it doesn't hurt much at all. if you get a glancing blow so the ball doesn't break, it will leave a nice welt, but it's certainly not life threatening, even to a cat.