One thing, you may put the 243, 260, 7mm-08, 270, 280, 308 all in a hat and pick one and not notice much difference, but the 6.5x284 will dominate all of them, it is held back by the 24" barrel of the savage lrh, but with a 26" or longer barrel that round will shoot .612 bc 140 bergers at 3100fps, none of the rest compare.
Technically, a 26" will produce a higher velocity than the 24". I have two 6.5x284's. My Cooper has a 26". My LRH Savage generates velocities within 20FPS of my Cooper and is equal to my buddy's 26" custom. With both my rifles, and others I have known, best accuracy is typically achieved at lower velocity than max anyway so it' might be academic anyway. What makes my LRH is that it will place it's shots in a baseball sized target at 1000 yards and delivers 1000 FP energy. This rifle will out shoot a lot of custom jobs. IMHO you might be shortchanging the LRH because of 2" of barrel.