I'm not asking about just threading a new barrel, there's smiths that face off the tapered part of the action and use a recoil lug for a shouldered 1.20 barrel
You either have to face off the action or turn the barrel to 1 ⅛". My customer wanted the barrel turned down to match the factory barrel. Tikka has plenty of tenon to do the shortening technique
I was told this was for a rebarrel. But he may have meant shouldered barrel with recoil lug but I know we didnt discuss anything other than the rebarrel