This upgrade set from Master Model is intended primarily for the Tamiya 1/350 King George V class battleships. These 10 barrels are machined from aluminum, and are a great improvement over the kit styrene ones.
These barrels are nice and light, and appear dimensionally accurate. They are a recommended upgrade for you KGV class battleship.
This set of barrels from Master Model #SM-350-012, are available via Georgetown Hobbies for $26.95, part #MAS350012.
Master Products are distributed in the US by Georgetown Hobbies and are available at the following stores.