I've got an old Magnum Sendero in 7MM RUM. The barrel never was a very good one and has gotten worse. I am entertaining the thought of going with a .338 cartridge in the new barrel. Can anyone tell me why I should go with a 338 Edge as opposed to a 338 RUM? I'm never going to be shooting at game in excess of 1,000 yards. Please be as detailed as you have time to be. Thanks for any and all responses.