Again, that depends. What is a fact, is you dont have a clue.
I'm not 100% sure I'm understanding what you're saying so I apologize if I'm reading it wrong, but penetration is absolutely determined by impact velocity, all else being equal. That doesn't mean higher impact velocity means more penetration. It just means that if you fire the same bullet put of a .308 Win and a .300 Win Mag and the impact velocity is the same, then penetration will be as well. At least in a perfect world. But unfortunately animals are not all the same and very minor changes in POI can significantly change terminal performance. A small sample size could change the results due to minor variations in manufacture, variations in the target, etc, but with a large sample size this will hold true.
