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These guns were designed by Vickers in 1914 with the prototype being proved at Eskmeals on 22 August 1917. They were intended for use on a class of Black Sea Fleet battleships with the first ship intended to be laid down in 1915-16. Only the prototype gun was completed, as the start of World War I halted progress on the battleships themselves. This prototype was designated by Vickers as No. 1712A and was known during the war as the "15 inch A" gun in order to hide its true size. "Pattern 1914" is my estimate.

As were other guns designed by Vickers for the Russian fleet, these were not wire wound guns. Construction consisted of tapered inner A tube, tapered A tube with Vickers cannelured rings between the locating shoulders. Over the A tube were B1, B2 and B3 tubes reaching to the muzzle. Over these were C1 and C2 tubes for about two thirds of the length of the gun. Over these were a jacket, a screwed collar and breech ring. The breech screw, held by the carrier, worked in a breech bush which was screwed into the C1 tube.

After being proved, the question arose as to what to do with this gun, as it was considered to be too heavy for use on land. Nothing was decided then, but on 23 March 1918 the Germans began shelling Paris with their 21 cm (8.27") Kaiser Wilhelm Geschütz guns (Paris guns) from a range of about 70 miles (113 km), creating a perceived need for a counter weapon. The British decided to convert the Vickers gun into a very long range 8.07" (20.5 cm) "super velocity" weapon to be known as the 8" sub-caliber Mark I. As modified, the A tube was cut back 42 inches (106.7 cm) from the muzzle and then it and the inner A tube were extended for 267.45 inches (679 cm) past the original muzzle by a new 2A tube. The B3 tube was cut back by 182.05 inches (462 cm) and was continued to the new muzzle by a B4 tube, with a screwed external guide ring joining the B3 and B4 tubes. A new full-length rifled liner was inserted into the 2A and inner A tubes. The rifling was based upon that discerned by examining fragments of the German 21 cm (8.27") projectiles.

Completed too late for the war in February 1919, it was fired six times in this configuration after which it was discovered that a crack had formed, ending its useful life. No more was done and the gun was scrapped in 1928.

Actual bore diameter of the British design was 16.0" (40.6 cm) as originally completed and 8.07" (20.5 cm) as reworked.

Gun Characteristics

Designation 16"/45 (40.6 cm) Vickers Pattern A
16"/45 (40.6 cm) Pattern 1914
406 mm/45 (16") Pattern 1914
8" (20.5 cm) sub-caliber Mark I
Ship Class Used On Black Sea Fleet Battleships
Date Of Design 1914
Date In Service Not in service

16"/45 (40.6 cm) Pattern 1914

Gun Weight (including breech mechanism) 107.7 tons (109.4 mt)
Gun Length oa 720 in (18.288 m)
Bore Length 698.45 in (17.741 m)
Rifling Length 565.5 in (14.364 m) 1
Grooves 0.12 in (3.05 mm) deep
Lands N/A
Twist N/A
Chamber Volume 33,000 in3 (540.8 dm3)
Rate Of Fire about 1.5 to 2 rounds per minute
  • ^It is believed that the start of the rifling for the 16" (40.6 cm) gun was slightly coned so that the full depth was not attained for about 8 inches (20 cm), similar to the Vickers 10" (25.4 cm) and 14" (35.6 cm) guns built for Russia.

8"/120 (20.5 cm) sub-caliber Mark I

Gun Weight (not including breech mechanism) 136.96 tons (139.1 mt)
Gun Length oa 987.35 in (25.079 m)
Bore Length 968 in (24.587 m)
Rifling Length N/A
Grooves (64) 0.1005 x 0.198 in (0.255 x 0.503 mm) 1a
Lands 0.198 in (0.503 mm)
Twist Uniform RH 1 in 45
Chamber Volume 11,500 in3 (188.5 dm3)
Rate Of Fire probably much less than 1 per minute 2a
  • ^Design of the rifling for the 8" (20.5 cm) gun was based upon recovered fragments of the German 21 cm (8.27") projectiles.
  • ^The German Kaiser Wilhelm Geschütz could fire about once every 20 minutes.


16"/45 (40.6 cm)

Type Bag
Projectile Types and Weights AP: 2,461 lbs. (1,116.3 kg)
HE: 2,461 lbs. (1,116.3 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 732 lbs. (332 kg) NCT
Muzzle Velocity 2,485 fps (757 mps) 1b
Working Pressure 16.3 tons/in2 (2,570 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
  • ^When proved in 1917 a muzzle velocity of 2,513 fps (766 mps) was recorded at a propellant temperature of 69 degrees F (20.6 degrees C) and a pressure of 16.6 tons/in2 (2,617 kg/cm2). This was for a propellant charge of 734 lbs. (332.9 kg) NCT with a grain size of 15.2 inches (38.6 cm) long, 0.79 inches (2.0 cm) outside diameter and 0.283 inches (0.719 cm) inside diameter. It was estimated that a charge of 765 lbs. (347 kg) NCT would result in a muzzle velocity of 2,600 fps and a pressure of 18.7 tons/in2 (2,950 kg/cm2). As NCT was not a normal British propellant, it would not have been used if this gun had seen British service in this caliber. The use of Cordite MD45, the most likely substitute, would have resulted in substantially lower muzzle velocities.

8"/120 (20.5 cm)

Type Bag
Projectile Types and Weights HE: 249 lbs. (113 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 313 lbs. (142 kg) MD oval, 0.60 x 1.20 inches (1.52 x 3.05 cm)
Muzzle Velocity 4,901 fps (1,494 mps) 1c
Working Pressure 29.47 tons/in2 (4,650 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun N/A

Shell design was based upon recovered fragments of the German 21 cm (8.27") projectiles. The shell body and driving bands for the British projectiles were pre-rifled.

All rounds were fired from the proof mounting with muzzle support. The planned service mounting, which allowed elevations between 40 and 58 degrees, was never completed.

  • ^The muzzle velocity given above was the highest achieved with the six rounds actually fired.


No range information for either configuration is available.

Mount/Turret Data

Designation N/A
Weight N/A
Elevation N/A
Rate of Elevation N/A
Train N/A
Rate of Train N/A
Gun Recoil N/A
Loading Angle N/A

The design of the Russian battleship mountings was never finalized. Alternative plans for the battleships include one designed for three quadruple turrets and one for three triple turrets.

The center of gravity of this gun was far forward, which would have meant that the battleship turrets would have been larger than standard British practice.


Data from:

  • "British Super-Heavy Guns Part 2" article by John Campbell in "Warship Volume III"

Page History

17 July 2007
11 February 2012
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