BL 6-inch gun Mk XIX

The majority of military planners before the First World War were wedded to the concept of fighting an offensive war of rapid maneuver which in a time before mechanization meant a focus on cavalry and light horse artillery firing shrapnel shells. Although the majority of combatants had heavy field artillery prior to the outbreak of the First World War, none had adequate numbers of heavy guns in service, nor had they foreseen the growing importance of heavy artillery once the Western Front stagnated and trench warfare set in. The theorists hadn't foreseen that trenches, barbed wire, and machine guns had robbed them of the mobility they had been counting on and like in the Franco-Prussian War and Russo-Turkish War the need for heavy artillery reasserted itself. Since aircraft of the period were not yet capable of carrying large diameter bombs the burden of delivering heavy firepower fell on the artillery. The combatants scrambled to find anything that could fire a heavy shell and that meant emptying the fortresses and scouring the depots for guns held in reserve. It also meant converting coastal artillery and surplus naval guns to field guns by either giving them simple field carriages or mounting the larger pieces on rail carriages.[2]

The Mk XIX was designed and built by Vickers specifically as a field gun, unlike its predecessors which originated as naval guns. Its length was reduced from the 45 calibres of its naval gun predecessors to 35 calibres, to reduce weight and improve mobility. The Mk XIX was a typical British built-up gun of the period constructed of steel with a central rifled tube reinforced with braided wire wound around the liner, a protective outer jacket, breech bush and breech ring.[3]

The Mk XIX was a breech-loaded design with a Welin interrupted screw breech and used separate-loading, bagged charges and projectiles. "The breech mechanism is operated by means of a lever on the right side of the breech. On pulling the lever to the rear the breech screw is automatically unlocked and swung into the loading position. After loading, one thrust of the lever inserts the breech screw and turns it into the locked position. The breech mechanism is similar to that used on the 8-inch howitzers both in design and operation".[3]

The Mk XIX utilized the same carriage and recoil mechanism as the BL 8-inch howitzer Mk VI. The carriage was a box trail with two large spoked steel wheels, a hydro-pneumatic recoil mechanism, and no gun shield. The carriages had an opening behind the breech to allow high angles of elevation. Due to the weight of the gun, it could not be towed by a horse team and had to be towed by a traction engine or artillery tractor instead.[3] The Mk XIX was most often used for long-range counter battery fire.

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  Rear left view
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  Rear right view
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  Breech
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  Example at the South African National Museum of Military History.
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  Diagram showing left elevation.
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  Diagram showing plan.
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  British Mk XVI HE shell, WWI.
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  Example at the Brazilian Army museum, Copacabana.

• List of field guns

• I.V. Hogg & L.F. Thurston, British Artillery Weapons & Ammunition 1914–1918. London: Ian Allan, 1972. ISBN 978-0-7110-0381-1
• Dale Clarke, British Artillery 1914–1919. Heavy Artillery. Osprey Publishing, Oxford UK, 2005 ISBN 978-1-84176-788-8
• Handbook of artillery: including mobile, anti-aircraft and trench matériel (1920), United States Army Ordnance Dept, May 1920
• Lewis, E. R. & Robbins, C. B. (2004). "Brazi's Coast Defense Rearmament, 1939–1945". Warship International. XLI (1): 52–53. ISSN 0043-0374.

Wikimedia Commons has media related to BL 6 inch Mk XIX gun.

• Handbook of the B.L. 6-inch mark XIX gun, on traveling carriage, land service, 1920 at State Library of Victoria
• Gun drill for 6-inch B.L. gun mark XIX carriages marks VIII and VIIIa 1920,1924 at State Library of Victoria