Here's a thought.

Since the bullet is the thing, a guy can get a simple set of drawing dies from Lee Precision and shoot 9.3 bullets in a .35 Whelen, reducing them from .366 to .358, and also of course still shoot .358's.

Moving up a caliber, I do this with my 9.3x57's, shooting .375 bullets that are resized to fit my 9.3's as well as 9.3's of course.

Case capacity is so similar that what the 9.3x62 can do the Whelen should be able to do, or nearly so, with small enough differences to be hardly noticed by game.