Send the rifle to Shilen, McGowan, or Douglas for a new barrel.
Many gunsmiths won't take the Howa actions in for rebarreling for two reasons:
1. There is a 1200 pound Japanese Sumo Wrestler who apparently installs barrels for them at the factory.
2. Threads are metric and are unavailable on many lathes.
NRA Endowment Member, NRA Certified Instructor
US Army veteran