You can convert the existing action and barrel to any chambering that uses the same boltface diameter and uses 7 mm or larger diameter bullets in a cartridge no longer than the 7 mm Mag. There are shops that will rebore and rifle the barrel for larger bullet diameters if you want to wildcat the 7 mm case to one? You can also get an entirely new barrel chambered.
The action's bolt will open will only so wide to allow cartridges in. You will have to limit your choices to that length. If you don't want to change the whole trigger guard and floorplate and magazine assembly, you will also have to limit yourself to what the existing magazine's length will allow? That's why I said the new cartridge couldn't be longer than the 7 mm mag, though your gun might have a little more room? You'll have to look.
All this having been said, the 7 mm case has roughly 10 grains more powder capacity than a .30-06 and about 25 more than the .308, putting it right in between these rounds and the .300 Win Mag for potential energy. So, it is already a pretty hard hitting round. I saw mention (but have not verified) of a statistic claiming large game is taken on the North American continent with fewer hits (2 on average) using .30-06 class cartridges than are needed shooting the big whammers (more than 2 hits on average). The explanation, if it is true, would be speculative. It could be the big guns just make more shooters flinch badly, given that accurate shot placement matters much more than cartridge size to getting a rapid stop?
Also, lower penetration is possible. Garrett's and Linebaugh's web sites, among others, describe instances of higher velocity rounds getting less penetration than slower ones using the same bullets. This is in test media. It is not explained, though I know the force acting on a bullet's overturning moment increases with velocity. Even if not actually tumbling, this means faster bullets would have a harder time staying aligned with their path through a medium, thus exhibiting higher drag. So, there seems to be a maximum penetration velocity for each bullet design.
Bottom line, you may already have something that will do what you want? Maybe not? It depends on what you intend to do with it, but keep that in mind before paying for a change.
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