Miscellaneous 2-pdr [4 cm (1.575")] Guns" Tony DiGiulian, 2-pdr [4 cm/39 (1.575")] QF Mark II, Mark II* and Mark II*C Tony DiGiulian, 2-pdr [4 cm/39 (1.575")]
ISBN 978-0-87021-459-2. Wikimedia Commons has media related to QF 4 inch Mk V navalgun. Gun drill for 4-inch Q.F. gun mark V (land Service) 1924 at State Library
The gun was originally designed to replace the older BL 5-inch (127 mm) navalguns. It was optimised for the modern smokeless propellants, such as cordite