. . . I would ask yourself OP:
Do 'I' like short actions, or no preference?
Do I WANT to shoot the 156-160?
Do I want/need factory ammo? Both made, Lapua via NORMA is loaded to safe max pressures, others not. . .
OR,
Just do like most 6.5 enthusiasts and get a rifle (or two) in each caliber and enjoy!
Steyr-Mannlicher Safe Bolt in .260 Rem
Atkinson Rifle Co. custom Mauser in 6.5x55 Swede