Lining rook rifles to 22 Hornet is pretty common and straightforward.
I have an Alex Henry falling block which has had exactly that done to it.
There are others out on the market, falling blocks and break actions.
An alternative is to find a rook with a poor bore and get it refined yourself, breathing new life into an unloved, unused rifle is quite rewarding.
Yes, I've restored a few shotguns from ugly ducklings to fine guns worthy of praise. Not sure that it was financially justifiable but it was fun to do.
If one looks hard enough you can sometimes find an already restored gun at a reasonable price.
