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Ordnance BL 5-inch gun Mks I – V
Mk I coast defence gun outside entrance to the Hong Kong Museum of Coastal Defence
Type	Naval gun Coast defence gun Field gun
Service history
In service	1880–1947?
Used by	United Kingdom
Wars	Second Boer War
Production history
Variants	Mks I – V
Specifications
Mass	Mk I – II  : 38 long hundredweight (1,930 kg) Mk III – V : 40 long hundredweight (2,030 kg)
Barrel length	125 inches (3,175 mm) bore (25 calibres)
Shell	50 pounds (22.68 kg)
Calibre	5-inch (127.0 mm)
Breech	de Bange
Muzzle velocity	1,750 feet per second (533 m/s)
Maximum firing range	8,700 yards (8,000 m)

The BL 5-inch guns Mk I – Mk V were early British 5-inch rifled breechloading naval guns after it switched from rifled muzzle-loaders in the late 1870s. They were originally designed to use the old gunpowder propellants. The 5-inch calibre was soon discontinued in favour of QF 4.7-inch.

Naval service

Guns equipped the following British warships :

• Mariner-class gunvessels of 1883
• Satellite-class sloops of 1883
• Comus-class corvettes as re-gunned in the 1880s
• Nymphe-class sloops laid down in 1885
• Calypso-class third class cruiser/corvettes of 1883–1884
• Iris-class cruisers as re-gunned in 1888
• Beagle-class sloops of 1889
• Bacchante-class corvettes as re-gunned in the 1880s

These guns also equipped several small gunboats of Colonial navies of Australia in the 1880s in response to the perceived threat of Russian expansionism in the Pacific (The "Russian scares").

Second Boer War (1899–1902) field gun

A number of guns mounted on carriages from obsolete RML 40 pounder guns accompanied the British siege train (heavy artillery) to South Africa. They were not required for the expected siege of Pretoria, which did not eventuate. Its usefulness in the field was limited by lack of a recoil control system, and the QF 4.7-inch gun was the most commonly used British heavy gun in the war.

Coast defence gun

The gun was installed as a conventional coast defence gun in South Africa and Australia, and several in the United Kingdom. Its more common use ashore in the UK was as "moveable armaments" in forts: on 2-wheeled carriages similar to field carriages but intended only for moving short distances to position guns for defence of the fort. These used either obsolete 40-pounder RML carriages or special high-mounting carriages for firing over parapets with recoil controlled by a hydraulic buffer built into the platform to which the carriage was fastened. A number were also set up in practise batteries adjacent to fortifications and batteries.

Ammunition

• Mk III and IV shrapnel shells
• BL 5-inch common lyddite shell Mk VIII diagram
• BL 5-inch gun 4lb 7.5 oz cordite cartridge Mark III diagrams

The gun was designed to fire a number of different types of projectile. Common shell could be used against earthworks, buildings and other vehicles and artillery. Shrapnel shell was designed for use against soft targets, such as troops or cavalry, at longer ranges – for soft targets within 400 yards case shot could be used. Palliser shot was designed for use against hard targets, such as enemy ships, where it could penetrate armour plate.

Initially, the gun used black powder propellant, but this was changed for Cordite propellant in the 1890s. Similarly, the black powder filling for common shells was changed for the much more powerful Lyddite filling, which increased the effect of the shell.

See also

• List of naval guns

Surviving examples

• A gun on the deck of HMS Gannet, Chatham, UK.
• 2 guns on 40-pounder RML field carriages, outside the Union Buildings, Pretoria, South Africa
• Outside the entrance to the Hong Kong Museum of Coastal Defence
• Two guns outside the old school gunnery offices at HMAS Cerberus, Royal Australian Navy training base south of Melbourne, Victoria, Australia
• No. 479 on Vavasseur mount at Queens Park, Maryborough, Queensland, Australia,
• A gun on Vavasseur mount at The Esplanade, Cairns, Queensland, Australia Archived 12 March 2011 at the Wayback Machine
• A gun on Vavasseur mount at the Maritime Museum of Townsville, Queensland, Australia

Notes

1. Mk I – Mk V = Marks 1 through to 5. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II. Hence this article covers the five models of BL 5-inch naval guns.

References

1. ^ Text Book of Gunnery 1902, Table XII page 336
2. Firing a 50-pound projectile with 15½ lb S.P. (gunpowder) or 4 lb 7¼ oz cordite Mk I propellant. Text Book of Gunnery 1902.
3. Winfield (2004). p.293
4. Preston (2007) p.182
5. Hall, June 1972
6. Hogg & Thurston 1972, pages 114-115

Bibliography

• Text Book of Gunnery, 1887. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE Archived 4 December 2012 at archive.today
• Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE Archived 12 July 2012 at archive.today
• Major D Hall, The South African Military History Society. Military History Journal – Vol 2 No 3 June 1972. Guns in South Africa 1899–1902 Part V and VI
• I.V.Hogg & L.F. Thurston, British Artillery Weapons & Ammunition 1914–1918. London: Ian Allan, 1972.
• Winfield, R.; Lyon, D. (2004). The Sail and Steam Navy List: All the Ships of the Royal Navy 1815–1889. London: Chatham Publishing. ISBN 978-1-86176-032-6. OCLC 52620555.
• Preston, Antony; Major, John (2007). Send a Gunboat: The Victorian Navy and Supremacy at Sea, 1854–1904 (2nd ed.). London: Conway. ISBN 978-0-85177-923-2.

External links

• Handbook of the 5-inch B.L. gun marks iv and v land service, 1890, 1895, 1903 at State Library of Victoria
• Handbook of the 5-inch b.l. gun marks IV and V on carriage disappearing 8-feet parapet India 1898 at State Library of Victoria
• Handbook of the 5-inch B.L. gun marks I-V land service 1904 at State Library of Victoria.
• Instructions for 5-inch Rifled Breech Loading Armstrong Gun and Elswick Hydro-Pneumatic Disappearing Carriage at Australian National Archives
• Diagram showing gun on siege carriage at Victorian Forts and Artillery website
• Tony DiGiulian, British 5"/25 (12.7 cm) BL Marks I, II, III, IV and V

• Naval guns of the United Kingdom
• 127 mm artillery
• Coastal artillery
• Victorian-era weapons of the United Kingdom