I will leave comments on calibers for combat to people who know. But for whitetail deer, I can't justify using a .22 centerfire of any caliber. It has been considered taboo all my life (40 plus years) and I don't understand why people suddenly think it is okay. A .243 should be the minimum for small to average deer and more gun for a long shot, or 200+ pound bucks. Respect the prey - use enough gun to reduce the risk of a lost deer.