I noticed SPR- bug holes.com has 6.5mm Bartlein Savage small shanked barrels. I realize the barrels need to be chambered, do they need threaded also for a barrel nut? On the other hand if not pre-threaded can they be shouldered into a Savage action, and if so what would be different from this barrel and Bartlein barrels regular blanks? Thanks just trying to learn something before talking to my gunsmith.