It seems to me that the rate of how fast the bullet expands would have the most effect on killing power. I have no way of knowing if Remington loads the same 150 grain pointed Core-Lokt into say a .300 Savage that they load into a .300 WM. A .338 bullet probably has a thicker jacket than a .308 bullet because it is intended for larger game animals. A deer is only 12 inches wide through the brisket and without hitting bone, that isn't a lot of resistance to fully expand a bullet. Then too it isn't the thickness of the jacket, but more the hardness of the jacket and the lead. I sure wish that I had made use of the company's Brinell metal harness tester for measuring bullets back when I had access to it. Thinner jackets on .257 caliber bullets are likely why they have the reputation of being faster deer killing bullets than the larger caliber bullets. I seem to remember that was the conclusion of that Carolina deer shooting study measuring the run distance after the shot on over 400 hunting preserve deer.
