On a serious note, .22 cal centerfires are capable of killing deer efficiently. The heavier bullets need a faster rate of twist so you need to make sure that your gun can handle the bullets. Even with the right bullets you have to be carefull at the shot. It's very important to not take shots that angle towards you, the front shoulder can mess up your chances if it's hit on the way in. If you have the proper setup and your patient enough to wait for a clear broadside shot, go for it. Hunters love a challenge.