Agreed between the two, I would go with the 338 Win Mag. I am not sure of all these new WSM cartridges. I was trying to decide between the 300 WSM and the 300 WM and went with the 300 Win Mag. These are tried and true, have been around along time and will be. Everything on the WSM is just speculation at this point. Will they be around in 50 years, or is it just a fad?