Gee, sorry--but this statement in your post prompted my comment:

"It seems to me that at one time; as the diameter of the bullet increased so did the thickness of the jacket and perhaps the change in the core. That is a 338 bullet would be built “tougher” than a 308 bullet. I don’t think that’s necessarily true now."

Is that not what you meant to type? Or did you mean something completely different?

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck