I see no reason you can't cut that barrel down and crown it yourself. Brownells and Midway sell a crowning tool that is not expensive and does a fairly good job. Touching up the muzzle is what they invented cold blue for. If necessary, you might try to find a local machineshop that has a lathe with a hollow headstock and they won't even need to remove the barrel, just the stock. If you get the crown right, there should be no impact on accuracy and little on velocity.
(If you decide to go to someone other than a gunsmith, make sure they know about the job and can do it while you wait for legal reasons.)