Given the 'tactical' rifle platform, that translates to rounds feeding from a detachable magazine.
With that in mind, the .260Rem can become limited in c.o.a.l. with long VLD bullets seated optimally in that case.
That's a reason why the 6.5Creed is so popular. Along with having good, affordable factory match ammo, the reloader can seat 140s out long in the Creed and not be constrained by limited magazine length. In short, when both cases are seated to mag. length, the 6.5Creed gives up very little (if anything) to the .260Rem. There are ways around getting the .260Rem to reach potential, but the short story is, the 6.5Creed is plain more easy to run...
That all said, if specifically wanting a 6.5, I'd do a 6.5x47L. Super dooper brass that lasts forever, efficient case design that will shine in a handy 22-24" barrel length, and the higher pressure case allows for about the same velocity of the 6.5Creed. In short (again), the 6.5x47L is more efficient 6.5Creed, with waaay better brass to feed it...
Now that those three are clear as mud, you could dust everyone with a 6.5SAUM, running a 140 @ 3150fps speed limit!!! 8)
That wicked performance comes at the cost of more powder burn and quite a bit more muzzle blast. Not really practical, from a tac shooter perspective, but it'd work in a pinch... ;D
Taking all of that into consideration, I'm building a 6x47L with a 23" Bartlein for a new Tac match rifle!
Have fun deciding! There really isn't a bad choice in the bunch...