BL 9.2-inch Mk I – VII naval gun

British 9.2 inch guns originated from a request by the Admiralty in 1879 for a gun comparable to Krupp's 24 cm MRK L/25.5, a very powerful 9.45 inch gun tested in August 1879. The Admiralty submitted its request to the Committee on Ordnance, which was considering returning to breech-loading artillery after Britain's brief return to muzzle-loaders in the 1860s and 1870s. A new breech-loading gun with a 9.2-inch (234 mm) bore, firing a 380-pound projectile was calculated to be suitable.Hogg & Thurston 1972, page 164 A total of 19 Mk I and Mk II guns of 26 calibres were made starting in 1881, but after lengthy delays and modifications they proved unsatisfactory and none made it to sea.

The 31.5 calibres versions, Mk III through to Mk VII became the first to be mounted on ships and deployed in general service.

File:BL 9.2 inch gun training circa 1896.jpg

File:HMSAustralia forward 9.2 inch gun.jpg, 1893}}]]

Guns equipped the following ships :

• Imperieuse-class armoured cruisers launched in 1883 : Mk III
• Orlando- class armoured cruisers launched 1886 : Mk V & VI
• Blake-class protected cruisers launched 1889 : Mk VI
• Edgar-class protected cruisers launched 1890 : Mk VI
• HMS Alexandra as re-gunned in 1891
• HMS Rupert as re-gunned in 1892
• M15-class monitors M19 – M28 launched 1915 : Mk VI guns from Edgar-class cruisers.

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Most Mk IV guns and some Mk VI guns were used in coast defences.

In the mid-to-late 1880s successful trials were carried out with RML 9-inch coast-defence guns firing at high angles in order to test the effectiveness of plunging fire on decks of ships. When surplus BL 9.2 inch Mk IV and Mk VI guns became available in the 1890s they were likewise adapted to high-angle carriages, with their obsolete 3-motion breech mechanisms replaced by modern continuous-motion patterns to allow faster loading. Locations included Hawkins Battery near Plymouth and Gibraltar.Hogg & Thurston 1972, page 167

The elevation of up to 45° meant that the shell was at risk of slipping back after being rammed forward as only the copper driving band held the shell in place in a BL gun, and they had not been designed to operate at such high angles. The solution adopted was to develop a special high-angle reduced-charge cartridge with a hollow up the centre, through which the gunner inserted a {{convert|1+1/4|in|mm|adj=mid|-diameter}} stick about 40 inches long made of beech wood, to prevent the projectile from slipping back before firing. A "light" {{convert|290|lb|adj=on}} shell was used for high-angle firing, rather than the standard {{convert|380|lb|adj=on}} shell.Treatise on Ammunition 10th Edition, published 1915. Pages 77, 142. High-angle cartridges were 44lb 12 oz or 16 lb 1 oz cordite MD, firing a 290-pound shell.

In the late 19th century to early 20th century five Mk IV coast-defence guns were installed at Singapore : two at Fort Connaught on Blakang Mati, one at Fort Siloso on Sentosa Island and two at Fort Pasir Panjang on Singapore Island.{{Cite web |url=http://www.fortsiloso.com/museum/9-2/9-2in.htm |title=The Gun Museum. 9.2-inch BL guns |access-date=15 July 2010 |archive-url=https://archive.today/20100111013315/http://www.fortsiloso.com/museum/9-2/9-2in.htm |archive-date=11 January 2010 |url-status=dead |df=dmy-all }} Two of these remain at Fort Siloso.

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{{main article|BL 9.2 inch Railway Gun}}

File:BL 9.2 inch Railway Gun Maricourt September 1916.jpg, Battle of the Somme, September 1916}}]]

From 1915 onwards Elswick adapted a small number of Mk III, Mk IV and Mk VI guns, and mounted them on railway truck mountings for service on the Western Front in France and Belgium.Hogg & Thurston 1972, page 168-170

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In the late 1880s and early 1890s the Australian colonies between them ordered 10 barrels and nine carriages for BL 9.2 inch Mk VI 'counter bombardment' disappearing guns:David Spethman, "The Garrison Guns of Australia 1788–1962", published by Ron H Mortensen, Inala, QLD 2008. {{ISBN|978-0-9775990-8-0}}

• New South Wales : Three went to protect Sydney Harbour, plus an extra barrel. Of these, one went to Ben Buckler Gun Battery, one to Signal Hill Battery, and one to Steel Point Battery. The barrel of the gun that had been installed at Signal Hill Battery survives on public display at the Royal Australian Artillery Museum at North Fort, North Head. The gun and carriage of the Ben Buckler gun were unearthed in 1984 and await restoration.
• Victoria : Four guns went to Victoria to protect Port Phillip, with two going to Fort Nepean and two going to Fort Queenscliff.
• South Australia : In 1888, South Australia purchased two guns for what was to be Fort Glenelg to protect Adelaide, South Australia. However, the residents of Glenelg, concerned that they might become a military target, were able to block construction of the Fort and so the guns were never installed. The British government bought them back in 1915.P.A. Richardson, 1987, Fort Glenelg: The Fort that Never was, University of Adelaide.{{Cite web |url=http://www.heritage.nsw.gov.au/07_subnav_01_2.cfm?itemid=5056455 |title=Heritage Branch Website - Online Database |access-date=18 January 2009 |archive-date=24 October 2008 |archive-url=https://web.archive.org/web/20081024035030/http://www.heritage.nsw.gov.au/07_subnav_01_2.cfm?itemid=5056455 |url-status=dead }}

File:BL 9.2 inch gun ammunition diagrams.jpg|{{center|Ammunition for early Armstrong 25 calibres gun}}

File:BL 9.2 inch Palliser shell diagram.jpg|{{center|Palliser shell}}

File:BL 9.2 inch Boxer shrapnel shell diagram.jpg|{{center|Boxer shrapnel shell}}

• 2 Mk IV guns at Fort Siloso, Sentosa Island, Singapore
• [https://www.flickr.com/photos/9977224@N06/1570862240 EOC Mk VII gun No. 7318 dated 1881, originally mounted at Signal Hill, Vaucluse] at [https://web.archive.org/web/20080611050407/http://www.northfort.org.au/ Royal Australian Artillery National Museum], North Head, Sydney, Australia
• [http://www.heritage.nsw.gov.au/07_subnav_02_2.cfm?itemid=5056455 A previously buried disappearing gun at Ben Buckler, Sydney, awaiting restoration] {{Webarchive|url=https://web.archive.org/web/20071231062234/http://www.heritage.nsw.gov.au/07_subnav_02_2.cfm?itemid=5056455 |date=31 December 2007 }}

1. One Mark I located in Port Royal, Jamaica, on the shores at Fort Charles. Stamped with Mark I 9.2 inch 22 ton gun lying next to its battery and Powder House. Taken out of service after the 1907 earthquake.

• List of naval guns

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• [http://cgsc.cdmhost.com/u?/p4013coll11,222 Text Book of Gunnery, 1887. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE] {{Webarchive|url=https://archive.today/20121204140418/http://cgsc.cdmhost.com/u?/p4013coll11,222 |date=4 December 2012 }}
• [http://cgsc.cdmhost.com/u?/p4013coll11,230 Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE] {{Webarchive|url=https://archive.today/20120712182551/http://cgsc.cdmhost.com/u?/p4013coll11,230 |date=12 July 2012 }}
• Treatise on Ammunition, 10th Edition 1915. War Office, UK. Facsimile reprint published by Imperial War Museum and Naval & Military Press, 2003. {{ISBN|1-8434-2560-2}}
• Hogg, I.V. and Thurston, L.F. (1972). British Artillery Weapons & Ammunition 1914–1918. Ian Allan, London. {{ISBN|0-7110-0381-5}}
• Tony DiGiulian, [http://www.navweaps.com/Weapons/WNBR_92-31_mk3.htm British 9.2"/31.5 (23.4 cm) Marks III to VII]

{{Commons category|BL 9.2 inch gun Mk I - VII}}

• [https://www.youtube.com/watch?v=UN1tOVzFrWY Video : Demonstration of breech operation]
• [http://recordsearch.naa.gov.au/scripts/Imagine.asp?B=4039831 "Instructions for 9.2-inch Breech Loading Armstrong Gun, and Automatic Barbette Centre Pivot Mounting"] instructions for 25.5 calibre Armstrong gun, apparently as supplied to Australian colonies. From National Archives of Australia
• Tony DiGiulian, [http://www.navweaps.com/Weapons/WNBR_92-26_mk1.htm Britain 9.2"/26 (23.4 cm) Mark I 9.2"/26 (23.4 cm) Mark II]

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Category:Naval guns of the United Kingdom

Category:234 mm artillery

Category:Victorian-era weapons of the United Kingdom

Category:World War I naval weapons of the United Kingdom

Category:Coastal artillery

Category:Disappearing guns