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Ordnance BL 10 inch gun Mk I - IV
1880s 10 inch breech loading gun side HKMCD 300px.JPG
Mk I coast defence gun, Hong Kong Museum of Coastal Defence
Type Naval gun
Coast defence gun
Place of origin United Kingdom
Service history
In service 1885 - 19??
Used by Royal Navy
Production history
Variants Mk I, II, III, IV
Weight Mk I : 32 tons barrel & breech
Mks II - IV : 29 tons[1]
Barrel length Mk I : 317.5 inches (8,064 mm) (31.75 calibres)
Mks II - IV : 320 inches (8,128 mm) (32 calibres)[1]

Shell 500 pounds (226.8 kg)[1]
Calibre 10-inch (254.0 mm)
Muzzle velocity 2,040 feet per second (622 m/s)[2]
Maximum range 10,000 yards (9,100 m)[1]

The BL 10 inch guns Mks I, II, III, IV[3] were British 32-calibres naval and coast defence guns in service from 1885.


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 [4] 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

Aft guns of HMS Renown

Mks II, III and IV guns were interchangeable and equipped the following warships :

25-ton gun for Victoria

A 25-ton version with a bore 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.[5] 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.[6]

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.[7]

See also

Surviving examples

Notes and references

  1. 1.0 1.1 1.2 1.3 Text Book of Gunnery 1902, Table XII Page 336
  2. 500 lb projectile, with 252 lb brown prism powder (gunpowder) or 76 lb cordite propellant size 30. Text Book of Gunnery 1902
  3. Mks I, II, III, IV = Marks 1, 2, 3, 4. Britain used Roman numerals to designate marks (models) of ordnance until after World War II. Hence this article covers the four models of British BL 10-inch guns.
  4. Hogg & Thurston 1972, page 176
  5. Manual for Victorian naval forces 1887. HMVS Cerberus website
  6. David Spethman, "The Garrison Guns of Australia 1788-1962" page 89, published by Ron H Mortensen, Inala, Qld, 2008. ISBN 978-0-9775990-8-0
  7. DiGiulian


External links

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