The BL 10 inch guns Mks I, II, III, IV were British rifled breechloading 32-calibre naval and coast defence guns in service from 1885.
== History == The British 10-inch calibre originated with the Committee on Ordnance in 1879 when it ordered a new 10.4-inch gun together with the new 9.2-inch as part of its transition from muzzle-loading to breech-loading guns. The proposed 10.4-inch gun eventually went into service in 1885 as a 10-inch gun firing a 500-pound projectile. After Mk IV of 1889 the Royal Navy discontinued the 10-inch calibre in favour of 9.2-inch and 12-inch.
Naval service
Mks II, III and IV guns were interchangeable and equipped the following warships :
Victoria-class battleships laid down in 1885 Centurion-class battleships laid down in 1890 Renown laid down in 1893 Devastation-class battleships as re-gunned in 1890
=== 25-ton gun for Victoria === A 25-ton version with a barrel of 300 inches (30 calibres) and firing a 450-pound projectile was supplied in 1884 to the Australian colony of Victoria, mounted on the gunboat HMVS Victoria. This gun was subsequently replaced on Victoria by an 8-inch gun, and in 1887 was mounted at Fort Franklin as a coast defence gun.
== Coast defence gun == Mk I was an Elswick Ordnance design used only for coastal defence. Mks II, III and IV were interchangeable Woolwich Arsenal designs used on warships but also for coastal defense around the British Empire, some on disappearing carriages.
== See also == List of naval guns
== Surviving examples == Hong Kong Museum of Coastal Defence Portsea, Victoria, Australia Fort McNab, Halifax, Nova Scotia, Canada
Notes and references
== Bibliography == Text Book of Gunnery Deprecated link archived 12 July 2012 at archive.today, 1902. London: Printed for His Majesty's Stationery Office, by Harrison and Sons, St. Martin's Lane I. V.Hogg & L. F. Thurston, British Artillery Weapons & Ammunition 1914-1918. London: Ian Allan, 1972. Tony DiGiulian, British 10"/32 (25.4 cm) Marks I, II, III and IV
External links
Handbook for the 10 inch B. L. gun, 1892, 1895, 1900, 1904 at State Library of Victoria Instructions for 10 inch rifled breech loading Armstrong gun and automatic naval carriage and slide Describes 25-ton gun supplied to Victoria. From Australian National Archives Mk III disappearing mounting diagram Archived 3 March 2016 at the Wayback Machine at Victorian Forts and Artillery website Elswick Mk I coastal defence barbette mounting diagram at Victorian Forts and Artillery website