Let's not forget that the .350 Rigby Magnum (rimless) was once a popular medium bore in Africa back in the day (prior to World War II).

[Linked Image]
http://www.kynochammunition.co.uk/

Ballistics:
225 gr bullet (.358") at 2625 fps (24 inch barrel)

That sure is very similar to the current Federal factory loading of a 225 gr bullet at 2600 fps for the .35 Whelen. Also, the 9x57 Mauser (.356" nominal groove diameter) with a 247 gr bullet at around 2300 fps was not that much different from the .35 Whelen with a 250 gr bullet at 2400 fps (factory ammo specs).

From my reading, it seems that the .350 Rigby was never really meant to be regarded as a dangerous game cartridge though there were 225 gr solids available. (Note: a 225 gr .358" bullet is lacking in sectional density compared to the more traditional African dangerous game cartridges and bullet weights.) It seems that the .350 Rigby was regarded as a fine plains game cartridge and so was the 9x57 Mauser. The .35 Whelen fits into the same ballistic niche.

Now, that said, I'm a big fan of the 9.3x62 but I also own a .338 Win Mag, a .35 Whelen, and a .375 H&H. (I must be a medium bore loony! grin) I once owned a .338-06 (I never hunted with it) but I sold it when I acquired my 9.3x62. And, I also like my .30-06 especially when loaded when 220 gr bullets. grin

Just my ramblings....
Cheers!
-Bob F.