350 MAG is one of the original short magnums. As I recall, Remington introduced this cartridge during middle years of LBJ in the Oval Office.
Gun writers criticized this cartridge and the model 600 carbine. Yet hunters across North America bought it and liked the way it downed large animals. In 2003, Remington responded to numerous letters asking for the 600 again. This time, Remington built it a little differently and called it the model 673. 350 MAG was one of many cartridges available in this handsome rifle.
This rifle never really sold well. 350 MAG did not get any fresh press from the shooting industry and the cartridge has faded again. In my opinion, it should be more popular than it is. The only factor which would keep me from buying a 350 MAG would be ammo supply. I'm not sure how to predict production volumes and availability. In contrast, 35 Whelen is still chambered in new rifles. Ammo production is still current. In a pinch, a knowledgeable handloader could enlarge case mouth of 30-06 to form 35 Whelen cartridges.
Good hunting to you.
Jack