Hi!
Yes, the barrel can be re-lined and I have one that was done many years ago before I purchased it but have no idea where to direct you. It would be less costly to find a used barrel, I have seen decent ones at gun shows for less than $50 but if you go that route make sure it has good dovetails for the sights & magazine ring.
It is probably worth mentioning that if "you" are going to take the rifle apart remember that the magazine ring rotates out of the dovetail. I have seen too many nice Model 14, Model 25, & Model 12 barrels where the ring has been driven out, once done it's quite difficult to fix.
Good luck with your project!
Jim
relining 12A
Re: relining 12A
Jim Peterson