30-378 is cool, so is a 300RUM, But if your going custom Go 300 Tomahawk, 300 RUM Improved, take some taper out of the case put a 35 degree shoulder on it and then stuff it with a whole bunch of powder topped of with a 240 grain SMK goin 2900fps and hold on!! Why because it's really cool and kills anything you want really far away. Stickin with a factory gun I guess it really doesn't matter one way or the other if money isn't a concern. Both are accurate and ballistically close. Whichever you prefer or think you'll be the most happy with is what you should get. Non-Weatherby fans bash Weatherbys and Weatherby fans bash everything but Weatherbys. I like them all!!