Elswick gun orders and hidden calibers

The suspected 18-inch gun development program remains a working hypothesis whose archival trail may use a concealed caliber. A label such as a 15-inch special could hide the actual weapon, making ordinary orders, cover designations, and development work difficult to separate. Another possibility is a difference between 13.5-inch special labels in London records and 14-inch specials at Elswick. A nominal foreign order could explain a caliber that otherwise fits British construction practice poorly. Establishing what was being developed requires identifying those naming conventions, rather than treating a suspected label as proof of an 18-inch weapon.