My solution was that I picked up a used Ruger M77 Hawkeye African in .375Ruger.
Most of the bush type planes I’ve seen and/or flown would have no problem accommodating a rifle in a case up to a 24” bbl. The super cub I flew had a Kolpin case mounted to the wing struts (bungee cords) so most any scoped rifles (not AR’s) would fit.
Ammo would be my concern. I had my MkX returned to .30/06 from .338-06. Between Finn Aagard anc John Barsness and others, I’d be inclined to go with a .30:06 and either 200gr NP or Swift A-frame.
My observations on Alaska cartridges is that residents carry .30/30’s .30/06, 7.62x54R, .45/70 and .308’s. Guides, outfitters, non residents carry MAGNUMS. Visiting the Walmart’s in Anchorage and Talkeetna was enlightening. Saw lots of .375H&H, .458winmag! 11varieties of .45/70. 1 or 2 varieties of most Weatherby magnums. Crates of .30/30, .30/06, and 12ga.
Unless I had access to an available action at bargain price and likewise barrel, Ect, I’d just buy a used bolt action .30/06 and cut barrel to 20” and replace front sight.
Or do as I did and buy a lightly used heavy hitter.
I have $425 in for the .375Ruger. $200 for a Savage 110 in .300RUM, and $250 for a Weatherby Vanguard.257! Nobody wants to pony up for the Ammo!
If you do decide on a 98 Mauser action (or variant) pm me. I have a A&B 24”.338-06 bbl, Lee dies, brass and bullets I’d consider letting go of.