Do you just want to shoot out past 1,000 yds, or are you wanting something lethal on big game out to 1,000 yds?
No reason to swap any barrels IMO. My 18" Tikka 6.5 Creed is lethal out to 800 yds at my altitude with reloads. Factory ammo is definitely enough to shoot out to 1,000 yds. This is the easy button in my opinion. I have nearly every caliber in Tikkas from 7PRC down to 223 and they all do basically the same thing. I sure enjoy shooting my 6mm's and below though compared to my lightweight 7PRC...