We're talking handguns, right? When you find a bullet caliber, weight, velocity combination that will consistantly penetrate an animal broadside and not quite exit the animal's hide on the opposite side, you've found the optimum round for that particular animal. You've expended 100% of the energy on the animal during the expansion phase of the bullet and nothing on the trees and rocks. For me, that has been a jacketed softpoint for deer size game. Heavy bullet and long barrel.