Relining a barrel is done all the time. I have a 30/30 94 out to be lined to 25/35, should be getting it back in about 2 weeks. The only problem you might run into is the thickness of the barrel at the muzzle. If there is not a lot of wall thickness, like on a lightweight rifle with a " pencil " barrel, it can't be done. Redman sells liners in 25 cal and might do the work for you, you can find his number in Shotgun news or Gun Digest. The fellow that did mine has retired form the business.
Mike