If you are building the biggest of the big, the Tamiya Yamato or Mushashi, Master Model may have just the upgrade that you need. Master Model SM-350-005 contains nine aluminum barrels for the 18.1-inch (460mm) main guns. As you can tell from the photographs, the barrels have the reinforcing bands near the base and the tube within tube construction of the guns is readily apparent at the muzzle.
Georgetown Hobbies is the distributor of Master Model barrels. The barrels are carried by many retail outlets, including AAA Model Hobbies and Pacific Front.