You can go to a Walmart and buy 325WSM ammo. If you lost your 350 Rem Mag ammo on a hunting trip you could be in trouble.
You can get a Kimber Montana in 325WSM but not in a 350 Rem Mag.
It shootes flatter.
The 325WSM is a more versatile hunting round in North America than the 350 Rem Mag. It shoots flat enough for antlope and is big enough for elk and moose at extended ranges.