QF 4-inch naval gun Mk I – III

Ordnance QF 4-inch gun Mk I, II, III
Australian troops with gun on a transport ship, circa. November 1914
Type	Naval gun Coast defence gun
Place of origin	United Kingdom
Service history
In service	1896 - 1920
Used by	British Empire
Wars	Boxer Rebellion, World War I
Production history
Designed	1895
Specifications
Mass	2,912 pounds (1,321 kg) barrel & breech
Barrel length	160 inches (4.064 m) bore (40 cal); 165.35 inches (4.200 m) total
Shell	Separate-loading QF 25 pounds (11.34 kg) Common pointed or Lyddite
Calibre	4-inch (101.6 mm)
Breech	Single-motion screw
Muzzle velocity	2,300 feet per second (700 m/s)
Maximum firing range	9,000 yards (8,200 m)

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 8 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, and from 11 February 1916, three guns, 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

The 4-inch QF gun on Hirta looking towards Dùn

• 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 outside the Elizabeth and Salisbury Navy Club in Elizabeth, 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

Bibliography

• Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE
• 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. 

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 at Victorian Forts and Artillery page