Barrel Life

I recently purchased a Weatherby Mark V 30-378. For Magnum calibers like this with high velocities I know they have a reduced barrel life. What will provide a longer barrel life: light bullets (150gr @ about 3500 fps) or heavy bullets (240gr @ about 2900 fps)? Maybe there isn't much difference but any input is appreciated.

You'll wear it out faster with lighter bullets than with heavy ones. Though I doubt you'll shoot something that kicks that hard enough to wear it out.

It's heat and hot loads that kill it. Find a nice medium velocity load that is accurate and let her cool down between shots and she will last a lot longer that you may think.