BL 15-inch Mk I naval gun

BL 15-inch Mark I naval gun
As mounted on monitor HMS Terror, 1915
Type	Naval gun
Place of origin	United Kingdom
Service history
In service	1915–1959
Used by	United Kingdom
Wars	World War I, World War II, Cold War
Production history
Designed	1912
Produced	1912–1918
No. built	186
Specifications
Mass	100 long tons (100 t)[1]
Length	650.4 inches (16.52 m)[1]
Barrel length	630 inches (16 m) L42
Shell	separate charges and shell
Shell weight	1,938 pounds (879 kg)
Calibre	15-inch (381.0 mm)
Recoil	46 inches (1.2 m)[1]
Rate of fire	2 rounds per minute
Muzzle velocity	2,450–2,640 feet per second (750–800 m/s), with supercharge
Maximum firing range	33,550 yards (30,680 m) (Mk XVIIB or Mk XXII streamlined shell @ 30°)[2] HMS Vanguard – 37,870 yards (34,630 m) @ 30°, with supercharges.

The BL 15-inch Mark I succeeded the BL 13.5-inch Mk V naval gun. It was the first British 15-inch (380 mm) gun design and the most widely used and longest lasting of any British designs, and arguably the most successful heavy gun ever developed by the Royal Navy.^[3] It was deployed on capital ships from 1915 until 1959 and was a key Royal Navy gun in both World Wars.