Huh??? Say what?

Zrex, I think you're fixated/obsessed with velocity, and looking at the temporary wound cavities which can be quite large - and yes, generally get larger with higher velocities (but, not always). That's okay. There's those that adhere to the high velocity school, and others that like larger calibers/projectile mass. There's so many theories on killing power out there that you could argue this stuff for years - and never come to a conclusion that all can agree on.
I sometimes like to think of it this way; would you rather get hit with a baseball going
90mph, or a bowling ball going 50mph. For sure, if that dang bowling ball goes thru ya'
it's going to leave a bigger hole in ya'.
Generally, greater mass/bullet weight equates to better penetration (momentum involved here). Push it faster, and all the better, but velocity and energy ain't everything. If it were, heck, we might could use a 220Swift for pachyderms.
There was one theory I came across that held bigger bullets at low/moderate velocity killed better due to the time the projectile spent in the quarry/target. Sort of the opposite of all that hydrostatic shock stuff.
In the end, probably just best to go with what has been proven to work best by those
who do the most shooting/hunting. The 30/30 has been knocking off deer and black bears (and bigger stuff, too) for a lot longer than I've been around, and I suspect it will keep doing so long after you and I are gone.
I'm not knocking the 243Win., but within 150yds., I'll put my trust in a bigger, heavier bullet, thank you very much.
BTW, folks that get gut shot with a 45ACP - they very often die! Check out any study of
law enforcement weapons, stopping powers, etc.