I just had to quote this on zrex!! You are saying the same thing everyone else is, you just don't want to admit it, lol. There is only one way for anything to pass through another object. In order for one object to pass through another object, it needs ENERGY to do so. If there is no energy in object A, there will be no damage to object B. Its that simple. Now, the energy may be different for different bullets, arrows, rocks, whatever, fact is you need energy to kill something. There is energy in the bow string. There is energy in the fire of the primer that sets off the powder charge. There is energy in the spring that releases the firing pin! Everything has energy. We all live because of energy. If it weren't for the energy of the sunlight heating the planet and making plants grow, nothing on earth would survive. Also the energy of the sun can kill a person, provided they don't act accordingly. It takes energy for your car to start, and energy for a bullet to go through a deer's chest!! Now how much energy is really needed I guess depends on the specific animal, and exactly where the bullet hits an animal, and how well that bullet transfers its energy to that animal!! Now, here is the point I think people are trying to make concerning where the .223 is not a good choice for deer!! If you hit a deer with a 55 grain Soft Point from a .223 in the Shoulder Blade, chances are, the deer will make it quitea ways. I wouldn't expect a 55 grain bullet at 2900 FPS would be able to penetrate completely through both lungs of a deer after striking the shoulder blade. Now take a .30-06 with a 165 grain bullet and put it through the shoulder blade. Big difference, it will go clean through and then some. I shot a cow a while back with my .223 (we were butchering one). I hit it with a 45 grain Speer soft point, in the head, just left of the eye, and slightly above. We never found the bullet. The bullet only contacted maybe 1/8" of bone total, and completely fragmented. Turned the brain to, well, lets just say "mush." Of course why wouldn't it with who knows how many tiny pieces of whatever going through in such a confined space. I don't know about you, but I sure wouldn't want to rely on a hole bunch of tiny bullet fragments going through a deer's chest for who knows how far, but rather a larger bullet that I know will make it all the way through without a problem!

Sorry for the long winded post, just couldn't help myself.