*British, WW1 & WW2, Breech Loading 4-inch Mk IX Naval Cannon*
This is an ex-conflict relic and was heavily burnt. It was bought from Stratford Armouries.
The BL 4-inch Mk IX naval gun was a British medium-velocity naval weapon introduced in 1917. Initially designed as secondary armament for Renown-class battlecruisers and Glorious-class “large light cruisers,” it is best remembered for its role as the primary armament on Flower-class corvettes during World War II.
The BL designation (Breech Loading) indicates that the gun is loaded from the rear of the barrel (the breech), rather than from the muzzle (the front). Breech-loading guns allowed for faster reloading and more efficient operation compared to earlier muzzle-loading designs, making them a significant advancement in artillery and naval weaponry.
History
World War I
The BL 4-inch Mk IX gun combined the barrel of the QF 4-inch Mk V with the breech mechanism of the BL 4-inch Mk VIII. It was first deployed in World War I on capital ships in triple-gun mountings designed for rapid, concentrated fire. However, this configuration proved impractical. Jane’s Fighting Ships of 1919 noted, “4-inch triples are clumsy and not liked. They are not mounted in one sleeve; have separate breech mechanisms, and require a gun crew of 23 for each triple.” Consequently, the guns were later mounted individually, typically on smaller vessels where they served as the main armament.
World War II
During World War II, the BL 4-inch Mk IX was extensively used on smaller warships such as Flower-class corvettes and minesweepers, primarily for engaging surfaced submarines.
At coastal defence installations, such as Fort Crosby near Liverpool, these guns were also employed for shore defence. On wartime transports, they served as auxiliary armament, as exemplified by their use aboard vessels like the St Essylt in Suez.
Legacy
The BL 4-inch Mk IX marked the end of British use of breech-loading (BL) 4-inch guns, as subsequent designs employed quick-firing (QF) systems with metal cartridge charges. It was succeeded by the QF 4-inch Mk XIX gun, which featured a heavier shell, lower velocity, and high-angle mounting for improved anti-aircraft capability.
*Condition*
This is a fascinating survivor from our WW1 and WW2 naval history. It is an ex-conflict relic that was heavily burnt and displays the expected age and service deterioration. Please see photographs as part of the condition report.
For display purposes the cannon has been mounted in the reversed position. Transport is at purchasers cost and would need to be arranged by the purchaser, we will give every assistance. Please contact us to arrange a viewing or visit it outside the Jolly Sailor, Portsmouth.
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