The way I was told (not to say that this is 100% true, but sounds right) is that the smaller the bullet, the more damage it does, causeing the animal to die quicker. It explodes inside the animal causeing internal bleeding. (now a 17 caliber would probably explode before it entered the animal, so I would most definetly never use a .17 Rim or centerfire at large game.) It could go both ways though, if the bullet causes internal bleeding, how could you follow a blood trail to the animal if its bleeding internally? ( this is if you shoot behind the shoulder). I know an experienced hunter that uses nothing but a 17 centerfire. He knows where to hit that deer to put it down in its tracks. He hits it in the neck or through the ear. I never known him to lose a deer . I would never use that small of a bullet to hunt deer. I disagree with him totally but he always tells me " this is to prove that I am a good shot, and experienced hunter" , he may be right, but what if he hits it and never finds it? In MD, the smallest caliber that is legal is a .223. I hear that virginia allows .22 hornets , but not exactly sure.