The QF 4-inch gun Mks I, II, III were early British QF (quick-firing) naval guns originating in 1895. They all had barrels of 40 calibres length.
== Naval service == The gun was intended to be a more powerful alternative to the quick-firing 3-inch QF 12-pounder gun, and a faster-firing replacement for the BL 4-inch gun. It was mounted on the following ships:
Pelorus-class third-class protected cruisers of 1896 Condor-class sloops of 1898 Cadmus-class sloops of 1900 Topaze-class third-class cruisers, launched in 1903 Invincible-class battlecruisers of 1906 Its 25-pound (11 kg) shell proved insufficiently powerful to make it much of an improvement on the 12-pounder. From 1907 onwards, it was succeeded in its class on new warships by the BL 4 inch gun Mk VIII, which fired a 31-pound (14 kg) shell.
== Coast Defence gun == From 1906, a number of Mk III guns were transferred from the Royal Navy for use as coast defence guns around the United Kingdom, and remained until 1939. In 1918, three guns were in service at Dover Garrison and eight at Forth Garrison.
== World War I land service == On 20 September 1914, the British cruiser HMS Pegasus was sunk by SMS Königsberg in Zanzibar harbour. Her eight QF 4-inch Mk III guns were recovered and used ashore in the East African campaign. Some were used as coast defence guns at Zanzibar and Mombasa. Two guns - three from 11 February 1916 - were used by 10th Heavy Battery manned by the Royal Marines, mounted on improvised field carriages and towed by Packard lorries, supported by six REO lorries carrying ammunition.
Surviving guns
A gun from HMS Pegasus used in the WWI land campaign stands outside Fort Jesus on Mombasa Island, Kenya, next to one of the 10.5-cm guns from SMS Königsberg. A gun from HMAS Protector is on display at the National Military Vehicle Museum in Edinburgh, South Australia. A gun was installed in 1918 on the island of Hirta in the St Kilda archipelago, northwest Scotland, after a German submarine attack there, by the German submarine SM U-90.
== See also == List of naval guns
Notes
References
== Bibliography == Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE Deprecated link archived 12 July 2012 at archive.today General Sir Martin Farndale, History of the Royal Regiment of Artillery : Forgotten Fronts and the Home Base 1914-18. London:The Royal Artillery Institution, 1988 Hogg, I.V. and Thurston, L.F. (1972). British Artillery Weapons & Ammunition 1914-1918. Ian Allan, London. ISBN 978-0-7110-0381-1.{{cite book}}: CS1 maint: multiple names: authors list (link)
External links
Drill for 4 -inch Q.F. gun (land service). 1914 at State Library of Victoria Gun drill for 4 inch Q.F. mark III gun (land service) 1924 at State Library of Victoria Tony DiGiulian, British 4"/40 (10.2 cm) QF Marks I, II and III Diagram of gun on garrison carriage Archived 4 March 2016 at the Wayback Machine at Victorian Forts and Artillery page
