The 4" QF gun served on a wide variety of Royal Navy vessels during World War Two, including many battleships, cruisers and destroyers. This High Angle (HA) Dual purpose (DP) gun and mount was refit to many ships over the course of World War Two to correct the shortcomings of the 4.7" SP gun. The Mk XVI was a popular weapon, and production could not meet demand until late in the war.

This gun, in the twin open HA XIX mount, was retrofit to most of the Tribals by the removal of the "X" CP XIX twin 4.7" mount.