BL 6 inch Mk VII naval gun

Infobox Weapon
is_artillery=yes
is_explosive= yes
is_UK=yes
is_ranged=yes


caption=On Mk II carriage, Reninghelst, Flanders, 15 June 1916
name= BL 6 inch gun Mk VII
origin= UK
used_by=
wars=World War I World War II
prod_date=
type=Naval gun
Coast defence gun
Heavy field gun
date=
designer=Vickers
design_date=1899
manufacturer=
service=1901 - 1950s
1915 - 1918 (field use)
caliber= convert|6|in|mm|sigfig=4
part_length=convert|269.5|in|m|sigfig=4 (45 cal)
carriage=
breech=
rate=
velocity=convert|2525|ft/s|m/s|sigfig=3 [2525 ft/sec with 100 lb projectile, 23 lb cordite MD size 16 propellant was the standard loading in WWI. The original loading was 20 lb of the more powerful cordite Mk I size 20, but Mk I caused greater wear] .
cartridge=HE convert|100|lb|sigfig=4 [Shell weights given are filled and fuze i.e. as fired. convert|100|lb|kg|sigfig=4 was standard shell weight in WWI. Some earlier shells had slightly higher weights e.g. Mk IV common lyddite shell weighed convert|101|lb|2|dram|kg|sigfig=4]
ammo_wt=
max_range=On Field carriage Mk. II : convert|13700|yd|m|sigfig=4 [Clarke page 23 quotes 13,700 yds on the Mk II carriage; General Farndale page 130 quotes convert|12000|yd|m|sigfig=4 - this is possibly on the Mk I carriage.] Naval : convert|14600|yd|m|sigfig=4 (light charge); convert|15800|yd|m|sigfig=4 (heavy charge) [Tony DiGiulian, [http://www.navweaps.com/Weapons/WNBR_6-45_mk7.htm British 6"/45 (15.2 cm) BL Mark VII] ] [All figures for convert|100|lb|sigfig=4 shell, which was standard in WWI.]
recoil=
weight=convert|16875|lb|kg|sigfig=4 (gun & breech)
25 tons (gun on field carriage)
length=
crew=
number=898
filling_weight=Lyddite : convert|13|lb|5|oz|kg|sigfig=4
Amatol : convert|8|lb|14|oz|kg|sigfig=4
Shrapnel : 874 balls @ 27/lb [Figures for WWI field gun. Hogg & Thurston 1972, Page 243] The BL 6 inch Gun Mk VII was a British naval gun dating from 1899, which was mounted on a heavy traveling carriage in 1915 for British Army service, and became one of the main heavy field guns in the First World War.

Naval gun

The gun was introduced on the "Formidable" class battleships of 1898 (commissioned September 1901) and went on to equip many capital ships, cruisers, monitors, and smaller ships such as the Insect class gunboat which served throughout World War II. [Tony DiGiulian, [http://www.navweaps.com/Weapons/WNBR_6-45_mk7.htm British 6"/45 (15.2 cm) BL Mark VII] ]

Mk VIII in Naval service was identical to Mk VII, except that the breech opened to the left instead of to the right, for use as the left gun in twin turrets.

Guns were mounted in the following ships :
*Formidable class battleships laid down 1898
*Cressy class armoured cruisers laid down 1898
*Duncan class battleships laid down 1899
*Drake class armoured cruisers laid down 1899
*Monmouth class armoured cruisers laid down 1899
*Challenger second class protected cruisers including "HMAS Encounter" of 1901
*King Edward VII class battleships "Commonwealth", "Dominion", "Hindustan", "King Edward VII", "New Zealand" laid down 1902
*Devonshire class armoured cruisers laid down 1902
*HMS Tiger, battle cruiser laid down 1912
*Centurion class battleships as re-gunned in 1902
*Iron Duke class battleships laid down 1912
*Humber class monitors as re-gunned in 1913 with guns from HMS Montagu
*M15 class monitor M27 of 1915
*Insect class gunboats of 1915

World War I field gun

They were first sent to France in 1915 mounted on improvised rectangular-frame field carriages designed by Admiral Percy Scott, based on the design he had improvised for 4.7 inch guns in the Second Boer War, and were successful. [Hogg & Thurston 1972, Page 144]

However, elevation and hence range was limited with the Scott carriages so a proper carriage, MK II, was introduced early in 1916, allowing elevation to 22°. Carriages Mks III, V and VI also appeared.

thumb|left|
Firing near Beaumetz-lès-Loges, cutting wire for the Australian advance Second Battle of Bullecourt 21 April 1917
It was operated by the Royal Garrison Artillery, as were all the larger guns, in World War I, in batteries of 4 guns.

Following its successful employment in the Battle of the Somme its role was defined as counter-battery fire and also they "were most effective for neutralising defenses and for wire cutting with fuze 106 [a new fuze which reliably burst instantly above ground on even slight contact, instead of forming craters] ", also for long-range fire against "targets in depth" [Farndale 1986 page 158, quoting War Office Artillery Notes No. 4 - Artillery in Offensive Operations, January 1917.] .

It was superseded by the lighter and longer-range BL 6 inch Gun Mk XIX which was introduced from October 1916 but the Mk VII remained in service to the end of World War I.

Coast defence gun

103 [Farndale 1988, Page 404] of these guns were in service in World War I in coastal defences around the UK. Some of these, together with others at ports around the wider British Empire, remained in service until the 1950s. In the German raid on Scarborough, Hartlepool and Whitby on 16 December 1914, a notable action was fought by Durham Company RGA of the Territorial Force at Heugh (2 guns) and Lighthouse (1 gun) batteries defending Hartlepool. They duelled with the German battlecruisers "Seydlitz" and "Moltke" (11 inch guns) and "Blücher" (8.2 inch), firing 112 rounds and scoring 7 hits. The battlecruisers fired a total of 1,150 rounds at the town and the batteries causing 112 civilians and 7 military killed. [Farndale 1988, Pages 368-369, 401.]

Ammunition

See also

*List of artillery#Towed howitzers and field guns
*List of artillery#Naval guns

urviving examples

* [http://www.firepower.org.uk Rotunda, Royal Artillery Museum, London]
* at [http://www.frontmuseum.fi/en.html The Front Museum, Lappohja, Finland]
* at Fort Dunree, Lough Swilly, Ireland
*Fort Siloso at Sentosa Island, Singapore
* at [http://www.newhavenfort.org.uk Newhaven Fort, Sussex, UK]
*Fort Ogilvie, Point Pleasant Park, Halifax, Nova Scotia

Notes

References

*Dale Clarke, [http://www.ospreypublishing.com/title_detail.php/title=S7883 British Artillery 1914-1919. Heavy Artillery. Osprey Publishing, Oxford UK, 2005]
*General Sir Martin Farndale, [http://www.naval-military-press.com/FMPro?-db=nmp%5fproducts.fp5&-format=nmpweb%2fdetail.htm&-lay=cgi&-sortfield=date&Co=NMP&search=History%20of%20the%20Royal%20Regiment%20of%20Artillery.%20Western%20Front%201914-18&-max=20&-recid=35933&-token.0=3668698&-find= History of the Royal Regiment of Artillery. Western Front 1914-18. London: Royal Artillery Institution, 1986]
*General Sir Martin Farndale, History of the Royal Regiment of Artillery. The Forgotten Fronts and the Home Base, 1914-18. London: Royal Artillery Institution, 1988.
*I.V.Hogg & L.F. Thurston, British Artillery Weapons & Ammunition 1914-1918. London: Ian Allan, 1972.
*Admiral Percy Scott, [http://www.archive.org/details/fiftyyearsinroya00scotuoft "Fifty Years in the Royal Navy"] published 1919

External links

* [http://www.navweaps.com/Weapons/WNBR_6-45_mk7.htm British 6"/45 (15.2 cm) BL Mark VII 6"/45 (15.2 cm) BL Mark VIII 6"/45 (15.2 cm) BL Mark XXIV]
*Ken Musgrave, [http://www.landships.freeservers.com/new_pages/musgraves_plans.htm Diagram of BL 6inch Mk VII Gun on Mk. 2 Carriage at Landships (scroll to bottom of page)]
*Per Finsted, [http://www.chakoten.dk/cgi-bin/fm.cgi?n=726 Om den engelske 6-tommers feltkanon 1914-1940 (in Danish)]