I have an arisaka mod.38 rebarreled to .257 roberts, a long barreled target rifle. It's been entirely satisfactory for the thirty years I've used it, and I'd have to be a lot better shot to need a better rifle.
I also have a mod. 96 Mauser 6.5 x55 that I use for hunting. It has been everything one could wish for as a deer rifle, and Scandinavia has found it adequate for moose for over 100 years.
If it were me, and I didn't already have a barrel that I wanted to use, I'd be happier with either of those two than a 6mm.
I'd be reluctant about the 260 Rem. because it just equals the 6.5x55 and needs A LOT more breech pressure to do it. That doesn't do anything for barrel life, although I'm sure the action will take it as well as most.