The .350 Remington Magnum out of a model 600 will kick the sh..snot out of you. I've GOT a .458, and I shoot it more...(though to be fair its not shot with elephant loads..
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The .350 has the same powder capacity as the .35 Whelen and will deliver identical ballistics. However, when you put that punch in a rifle that goes less than 7lbs well, there's no free lunch.
You can make some great "light" loads using .357 pistol bullets, but about nobody does...
I wanted one ever since I saw a Wally Tabor film where he took it to Africa and saw it literally blow a 600lb "antelope" off its feet at close to 200yds.
The big problem with the .350 Rem mag is Remington. Nobody but Remington ever made ammo or BRASS....and Remington doesn't support the round to any real extent anymore.
You can make brass from the larger magnum cases, but only serious enthusiasts are willing to consider that.
Generally speaking the short carbine barrels limited the performance and people wanting .35 Whelen power found it simply easier to just go with the Whelen and the action length needed for it. And, the bigger heavier rifles helped tame the recoil a bit more, as well.
Something like a new version of the 600 or model 7 with a good muzzle brake would be cool and wouldn't kick bad, but I wouldn't want to be within a dozen yards of anyone (but me) shooting it!