It's never a totally "logical" decision. For ONE GUN, and because you can always shoot 280 Rem ammo in the 280AI, I'd build a dream 280 rifle with the AI chamber, whether you shoot the AI ammo or not. But, except for the heaviest bullets that gives you 7mm Mag performance ina lighter, more pleasant to shoot and carry rifle than the .300 Mag., and the 6.5 just can't duplicate its potential in any sphere.