if you're hunting game (pidgeons/pheasants) or rodent killing (rats,squirrels etc.) you will want a .22, they are more powerful but slightly less accurate, but the larger slugs (pellets) almsot guarantee a kill on small critters. If you're target shooting or back-yard plinking (tin cans and the like) you will want a .177 (less powerful but will still shread a coke can no problem, in one side out the other) but the bullet travels faster making it more accurate. I however (because I'm very accurate) hunt game with a .177, I can almsot guarantee a clean body shot to most birds making it not cruel to do. Most people should avoid hunting with a .177 though as if you clip it or something the force won't be enoguh to kill it and it will be in aganoy, and believe me clubbing itto death or shooitng point-blank isn't fun at all. so basically .177 for targets .22 for game.

Yup .22 for Hunting .177 For Target shooting

get a 22 i have one and i can pick a quater at 75yards