If need is the sole basis of choosing a cartridge then we don't even need a 30-06 as the 308win provided ballistics that are only slightly behind.Then again do we really need the 308win,since the 300 savage is only slightly behind.Then do we really need a 300 savage because the 30-30 is only slightly behind ballistics wise.Lets just stick to choosing a cartridge that we would like to shoot instead trying to justify what we need.