The discussion contrasts useful intermediate calibres with compromises that merely inherit the disadvantages of both ends. A 16.5-inch weapon looks more promising than the often-suggested seven-inch cruiser gun. In the comparison given, it retains the 16-inch gun's rate of fire. Its projectile is nevertheless appreciably heavier because small increases in calibre produce larger increases in volume and mass.
Notable Point · 49:02-49:54
Why 16.5 inches could be a useful gun compromise
A 16.5-inch gun could retain a 16-inch weapon's rate of fire while delivering a meaningfully heavier shell.