LOL: I had a flash back to my favorite Family owned/operated BBQ joint & forced to select only two (2) entrees from a great list of tasty offerings! But if choices must be made: #2 & #5, (#6 tight 2nd).
1) Great collection of unique calibers
2) PG: I must use the ole cliche’ & one your PH will respect - select the caliber that will ethically do the job in short order for the largest PG trophy on your hit-list & that means you maybe over-gunned (if that’s possible) on the littler guys.
3) Set-up that caliber for a comfortable 200 - 225M Zero (that’s me) as accuracy for ethical shot placement is greatly more important than lobbing lead long-range.
4) DG: Completely different mindset - I believe, you cannot be over-gunned & long range is species specific but honestly < = 100M.
Buff: big target but not easy to pick the “right spot” on a squirming around black canvas w/ some bush > 100M. Spells d.a.n.g.e.r.
DG: PH best teacher & best to listen to the teacher - example: a caliber & scope set-up for a Leopard could differ greatly compared to Buff or Hippo.
Case capacity only matters if you can use it. A lot of Magnum cartridges are loaded to 95 to 102% of capacity with slow burning powders. So unless you use a faster powder at higher pressure or modify yhe chamber, leade, freebore and other stuff how are you going to get 14 % more powder in if the load is already at 102%?
Yes you need a bigger case to get bigger velocities but only if you have the powder speed to suit it.
In the early days a lot of calibers couldn't get the velocities to match the case size. Take the 25/06 you couldn't get enough of the powder in the day to SAFELY make it much faster than the 257 Roberts.
Only with the advent of slower powders did these cartridges and the magnums come into thier own.
Yes we have even slower powders and even bigger cases that take even more powder but are these 200 fps worth all the extra powder, recoil worth it. For some Yes.
As for the faster speeds out of the Whelen the wheel hasn't been reinvent people were doing the same as me 10 years ago in standard factory Remington rifles
That's close enough to 2,700fps in my book and in 2011 as well.