FWIW, a .358 on that action would certainly allow you to use the 225gr ABs, and have no COL issues. IF you can push it to 2600fps, this is what I get for #s:
yd. in. fps. ft-lbs.
50 0.448 2493 3105
100 0.983 2391 2856
150 0.006 2289 2617
200 -2.651 2190 2396
250 -7.146 2092 2186
300 -13.489 1999 1996
I use one of my .358s, similarly, though I don't push it that hard, and only count on about 2450 fr a 20" tube, but it still should get me to 300, with less energy, but less fuss. I don't feel a need for 2000 FPS or 2000 ftlbs for a deer or hog, with a 200+gr .358 pill.
If I was sitting on your action for a build, it'd be hard for me not to build another 22-23" 7x57 or maybe a 280/AI, for shooting from stands in TX. A new 'dream' 358 build would have a 20-21" tube and a mannlicher stock. I really think you can get all you want or need from a .358 in a 20-21" bbl, whereas a Whelen will make it's hay somewhere at <22". JMO
