I did re-read what you wrote slowly as suggested. You said that it is expanded diameter that matters rather than the slightly bigger than fingernail unexpanded diameter. But my question was if you used a mono bullet (perhaps a Barnes TSX) of the same weight in both a .338 and .358, that was of similar shape, what would be the factor which would make the expanded diameter of the .358 considerably larger than that of the .338 bullet so as to make the .358 bullet kill better (when the .338 bullet has much better sectional density)? I would have thought that because both bullets were of the same construction (all copper), same shaped nose, that the longer .338 bullet with better sectional density would expand nearly as much (especially being longer),but penetrate deeper because of sectional density being better. Assume same velocity of perhaps 2750 fps.
It doesn't effing matter. What you kill with one you'll kill with the other.
