I've killed quite a few with the .22 LR and .22 magnum. You definitely don't want any hyper velocity hollow points. I've seen them flatten and fail to penetrate the skull. Any of the 40 gr. LR solids will work if they hit right. From the side your aim point should be between the eye and ear hole. A LR solid will often go completely through and out the other side with that placement. It's best to avoid front on shots as the skull is very sloped and will sometimes glance off. The eye is definitely not the place to aim if they're facing directly at you as the bullet will completely miss the brain. It will work fine if the head is at a quartering to you angle though. The back of the head right between the ears also works well. That said, the .22 magnum works much better as it will completely penetrate the skull/head from any angle with no tendency to glance off even from the front from what I've seen.