View source for RBL 40 pounder Armstrong gun

{{Infobox Weapon
|name= Ordnance RBL 40 pounder gun
|image=[[File:RBL 40 pounder Tasmania 1902 AWM A04785 clipped 300px.jpeg]]
|caption=Launceston Volunteer Artillery, Tasmania, 1902
|origin= [[United Kingdom]]
|type= [[Naval gun]]<br>Fortification gun
<!-- Type selection -->
|is_ranged=yes
|is_explosive=
|is_artillery=yes
|is_UK=yes
<!-- Service history -->
|service=1860s - 190?
|used_by={{UK}}<br>Australian colonies
|wars= [[New Zealand Land Wars]]<br> [[Bombardment of Kagoshima]]
<!-- Production history -->
|designer=[[Armstrong Whitworth|W.G. Armstrong Co.]] 
|design_date=
|manufacturer=[[Armstrong Whitworth|W.G. Armstrong Co.]]<br>[[Royal Gun Factory]]
|production_date=1859 - 1863
|number=1013<ref>1013 were in service in 1877 : 819 35cwt & 194 32cwt. Quoted in Treatise on Manufacture of Ordnance 1877, page 150. Holley 1865, page 13 quotes 641 as at 1863 : 535 manufactured by Elswick Ordnance and 106 by the Royal Gun Factory. From the Report of the Select Committee on Ordnance, 1863.</ref>
|unit_cost=
|variants=32cwt, 35cwt
<!-- General specifications -->
|weight=32 cwt ({{convert|3584|lb|kg}}), later 35 cwt ({{convert|3920|lb|kg}}) gun & breech<ref name=Gunnery1887/>
|length=
|part_length={{convert|106.3|in|m|sigfig=4}} bore & chamber<ref name=Gunnery1887/>
|width=
|height=
|crew=
<!-- Ranged weapon specifications --> 
|cartridge={{convert|40|lb|2|oz|kg|sigfig=4}}<ref name=Gunnery1887>Text Book of Gunnery, 1887</ref>
|caliber={{convert|4.75|in|mm|sing=on|sigfig=4}}<ref name=Gunnery1887/>
|action= 
|rate=
|velocity={{convert|1180|ft/s|m/s}}<ref name=Gunnery1887>1180 ft/sec firing 40 lb 2 oz projectile with 5 lb RLG2 (gunpowder). Text Book of Gunnery 1887, Table XVI page 313</ref>
|range= 
|max_range=
|sights= 
<!-- Artillery specifications -->
|breech=Armstrong screw with vertical sliding vent-piece (block)
|recoil=
|carriage=
|elevation=
|traverse=
}}
The Armstrong '''[[British ordnance terms#RBL|RBL]] 40 pounder gun''' was an early attempt to use [[William George Armstrong, 1st Baron Armstrong|William Armstrong]]'s new and innovative [[Breech-loading weapon|breechloading]] mechanism for medium artillery.

==Design history==
[[File:RBL 40 pounder 35 cwt gun diagram.jpg|thumb|left|300px|<center>35 cwt barrel dimensions</center>]]
The Armstrong "screw" breech had already proved successful in the [[RBL 12 pounder 8 cwt Armstrong gun|RBL 12 pounder 8 cwt field gun]], and the British Government requested it be implemented for heavier guns despite Armstrong's protests that the mechanism was unsuited to heavy guns.<ref>Ruffell, The Armstrong Gun Part 5: British revert to Muzzle Loading</ref>

The first version weighed 32 cwt, followed by the 35 cwt version which introduced a longer and stronger breech-piece.<ref name=Treatise1877>Treatise on Manufacture of Service Ordnance, 1877</ref>

A 32 cwt variant having a horizontal sliding wedge breech instead of the Armstrong screw with vertical vent-piece was introduced in 1864 as an attempt to address the perceived weaknesses of the screw-breech design. It was withdrawn from service by 1877.<ref>Treatise on Manufacture of Service Ordnance, 1877. pages 89, 153</ref>

==Naval service==
[[File:RBL 40 pounder Armstrong gun HMS Warrior breech end.jpg|thumb|left|<center>Upper deck 35 cwt [[broadside]] gun on [[HMS Warrior (1860)|HMS Warrior]]</center>]]
The gun was recommended in 1859 for the Navy as a [[broadside]] or [[pivot gun]].<ref name=Treatise1877/>

An officer from [[HMS Euryalus (1853)|HMS Euryalus]] described the gun's performance at the [[Bombardment of Kagoshima]] of August 1863:
{{cquote|The 40-pounder we found answer exceedingly well, for coming out of the place [Kagoshima] we planted common shell, with pillar fuze, wherever we wished, at a range of 3,800 yards. Three steel vent-pieces broke, but another placed them immediately and no harm was done. These guns work very easily, are very true, and the drill is very simple.|20px|20px|Reported in ''[[The Times]]'', 25 April 1864.<ref>''The Times'', 25th April 1864 : 25 April 1864 THE ARMSTRONG GUNS IN JAPAN http://www.pdavis.nl/Japan.php</ref>}}

==Land service==
[[File:RBL 40 pounder sideclosing gun and carriage diagram.jpg|thumb|left|<center>Diagram depicting side-closing version on siege travelling carriage in position to fire over parapet</center>]]
The guns were typically employed mounted on high "siege travelling carriages" for use as semi-mobile guns in forts, firing over parapets.

====Colony of Victoria service====
The Australian colony of [[Victoria (Australia)|Victoria]] received six 35 cwt guns in August 1865. They were used as mobile coast fortification guns and later as field guns. Three of these guns are known to survive.<ref>Friends of the Cerberus Website : slideshow http://www.cerberus.com.au/reenactors/40_pounder_slideshow.html</ref>

====Colony of Tasmania service====
As a result of the [[Jervois-Scratchley reports]] of 1877 into the defence of Australian colonies following the withdrawal of British troops, the Launceston Volunteer Artillery Corps in Tasmania acquired 2 guns on late-model iron carriages with iron wheels<ref>David Spethman, "The Garrison Guns of Australia" page 49. 2008, published by Ron H Mortensen, Inala, Qld. ISBN 978 0 9775990 8 0</ref>, which they continued to operate until at least 1902.

==Surviving examples==
* [http://www.flickr.com/photos/9977224@N06/1373750199 A gun made by Royal Gun Factory in 1865] at [[Elizabeth Castle]], [[Jersey]]
* Restored gun No. 272 at Hastings-Western Port Historical Society Museum, Victoria, Australia
* Restored Gun No. 271 at [[Fort Queenscliff]], Victoria, Australia
* Unrestored Gun No. 268 in Como Park, [[South Yarra, Victoria]]
* A 40-pounder horizontal-wedge gun at [[Royal Armouries]], [[Fort Nelson, Portsmouth]]
* On board [[HMS Warrior (1860)|HMS Warrior]], Portsmouth, UK

==See also==
{{Commonscat-inline|RBL 40 pounder Armstrong gun}}
*[[List of naval guns]]
*[[Armstrong gun]]

==Notes==
{{Reflist|2}}

==References==
* [http://www.archive.org/details/treatiseonconst00offigoog Treatise on the construction and manufacture of ordnance in the British service. War Office, UK, 1877]
* [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]
* [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]
* Alexander Lyman Holley, [http://www.archive.org/details/treatiseonordnan00hollrich "A treatise on Ordnance and Armor" published by D Van Nostrand, New York, 1865]

==External links==
* [http://www.palmerstonforts.org.uk/art/40prRBLsiege.htm Diagram of RBL 40-pdr on siege travelling carriage] at Palmerston Forts Society website
* [http://www.palmerstonforts.org.uk/art/40pd.htm RBL 40-pdr on Platform, Medium No. 4] at Palmerston Forts Society website
* [http://www.nzetc.org/tm/scholarly/search/search.html?page-length=10&text=40-pounder 40-pounder use in New Zealand Land Wars] at New Zealand Electronic Text Centre
* W.L. Ruffell,  [http://riv.co.nz/rnza/hist/local/rbl40.htm Armstrong RBL 40-pr]
* W.L. Ruffell, [http://riv.co.nz/rnza/hist/arm/arm4.htm "The Armstrong Gun Part 4: Other Armstrong Equipments in New Zealand" - use ashore in New Zealand Land Wars]
*[http://www.riv.co.nz/rnza/hist/local/rbl40fig8.htm Diagram showing gun on block trail carriage]

{{VictorianEraBritishNavalWeapons}}

[[Category:Naval guns of the United Kingdom]]
[[Category:Artillery of the United Kingdom]]
[[Category:Elswick Ordnance Company]]
[[Category:120 mm artillery]]