Of the choices you listed, reasonable barrel life would eliminate the 6.5x284. If I were going with a 6.5 CM, I would go with a short action.I put a heavy CM barrel on my Savage long action and it would cycle but not nearly as well as on a short action. I just used a single shot follower. The 6.5-06 will feed reliably on a long action but I don't know about barrel life. All-in all, if you hand load I would go with the Swede. Lapua brass and high BC bullets make it a good choice. I recently went with a Criterion 270 barrel on my long action. The new Hornady 145gr ELD-X bullet gives the old 270 some added potential that did not previously exist. IMO.