RE: Fur caliber.....
200 yards or less is perfect range for the 221 fireball. it is traveling slower and i have never had any probs. with it. however with the 17 rem. works great to. however with factory ammo i would have to go with the 221 because a lot of the 17 rem. ammo will spash on impact.
i would go with a 20 inch barrel. 24 max. however the 20 will make it easier to swing and there won't be much loss in velocity