Reconditioning a worn barrel required heating it, contracting and removing the old liner, and fitting a replacement before the assembly cooled. Any warping could misalign the liner and compromise the entire gun, so the work depended on specialized industrial skill as well as heavy plant. The Royal Navy also maintained pools of barrels, mountings, spares, and experience around the 15-inch system. That installed base made a shift to a new calibre more costly than a simple comparison of gun performance suggests. On this reading, the choice of 14-inch weapons for the 1939 King George V class was political, while an improved 15-inch design could have used the existing support system more easily.
Notable Point · 27:17-29:45
Why the Royal Navy kept supporting the 15-inch gun
The re-lining of worn barrels leads into a broader point: a mature 15-inch support system shaped the Royal Navy's calibre choices.