Ok, to address your questions. Will the .300WSM have a shorter barrel life? Certainly, but what do you intend to use it for? If you intend to hunt with it, you won't need to shoot more then 3,000 rounds in a lifetime anyway. If you intend to punch paper it's still a great caliber. How long it will last is up to how hot you load the rounds. You could load it down to .308 levels and get the same barrel life as a .308. Or you could take advantage of the extra powder capacity and speed those rounds up. I push a 180 grain Nosler Accubond at 3150 fps out of mine. Would I punch paper with that load? Absolutely not! But my gun is intended to hunt with, not punch paper. With that load I get nearly 4000 ft/lbs of energy at the muzzle. The .308 just won't do that. So what's the advantage of the .300WSM? More velocity, more energy, less flight time. What's the disadvantage? More recoil, less barrel life, that's about it. So, as others have stated, your purpose for the weapon is going to weigh heavily on the choice. My suggestion? Get the .300WSM. If you like it, keep it. If you don't you can trade it for another gun. Either way you end up with a new rifle and that can't be wrong!