BL 13.5-inch Mk V naval gun

BL 13.5 inch Mk V gun
Rear turrets of HMS Thunderer
Type	Naval gun
Place of origin	United Kingdom
Service history
In service	1912 - 1940s (as railway gun)
Used by	United Kingdom
Wars	World War I World War II
Production history
Designer	Vickers
Designed	1909
Variants	Mk V(L) Mk V(H)
Specifications
Barrel length	Bore 50 ft 6 in (15.392 m) (45 cal)
Shell	H: 1,400 lb (635.03 kg) L: 1,250 lb (566.99 kg) HE, AP[note 1]
Calibre	13.5-inch (342.9 mm)
Elevation	Naval: 0° - 20° Railway: 0° - 40°
Muzzle velocity	H: 2,491 ft/s (759 m/s) L: 2,582 ft/s (787 m/s)
Maximum firing range	H: 23,740 yards (21,710 m) at 20° L: 23,820 yards (21,780 m) at 20° H: 40,600 yards (37,120 m) at 40° (World War II railway gun, with Super Charge)

The BL 13.5 inch Mk V gun^{[note 2]} was a British heavy naval gun, introduced in 1912 as the main armament for the new super-dreadnought battleships of the Orion class. The calibre was 13.5 inches (343 mm) and the barrels were 45 calibres long i.e. 607.5 inches (15.43 m). The guns were greatly superior to the unrelated earlier 13.5-inch (30-calibre) Mk I to Mk IV guns used on the Admiral, Trafalgar and Royal Sovereign classes completed between 1888 and 1896.
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