If you are thinking about building a 1:350 scale Bismarck or Tirpitz, either the venerable Tamiya version or the the Revell of Germany version, you'll be interested in these metal barrels from Master Model. Not only do they have the 15-inch main gun barrels, but also the 5.9-inch secondary and 4.1-inch heavy AA gun barrels. Shown here are the main gun and heavy AA barrels. The main guns are in a white metal, possibly aluminum, with the now traditional open muzzle. The instructions show how it is mounted within the plastic turrets.
The second set shown is that for the tertiary or heavy anti-aircraft gun barrels. These sixteen small barrels are of brass and are finely turned. In spite of their small size, they to have open muzzles, providing the best quality appearance. However, these barrels are for the early C/31 open mount found only on the forward half of the 4.1-inch/105mm mounts of Bismarck. The C/31 was a converted 88mm mount and could be easily distinguished from the mount designed specifically for the 105mm gun, the C/37. The most obvious difference is the raised covering over the breach blocks of the gun barrels on the C/37 mount, as the C/31 version had the blocks open. Although Tirpitz initially carried two C/31 mounts and six C/37 mounts, when she left Germany for Norway, both of the C/31mounts had been replaced with the newer mount. These barrels are therefore applicable for Bismarck but not Tirpitz.
Georgetown Hobbies is the distributor of Master Model barrels. The barrels are carried by many retail outlets, including AAA Model Hobbies and Pacific Front.