BL 6 inch guns Mk II-VI

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BL 6 inch guns Mk II-VI


6 inch BL Mk IV

General Information
Military designation: Ordnance BL 6 inch gun Mks II, III, IV, VI
Manufacturer designation: Ordnance BL 6 inch gun Mks II, III, IV, VI
Manufacturer country: United KingdomUnited Kingdom United Kingdom
Developer / Manufacturer: Royal Gun Factory
Elswick Ordnance Company
Development year: 1880
Production time: 1880 to 19?
Model variants: Mk II, III, IV, VI
Weapon Category: cannon
Technical specifications
Pipe length: Mk III: 25.53 caliber 3.891
Mk IV, VI: 26 caliber 3,963
Caliber :

6 inch (152.4 mm)

Furnishing
Charging principle: Breech loader

The BL 6 inch guns Mk II – VI were the second generation of British 6-inch breech loading guns . Developed by the Royal Gun Factory , they followed the first 6-inch breech loader, the relatively unsuccessful BL 6-inch 80 pounder gun developed by the Elswick Ordnance Company . Originally, they were intended to use the existing black powder propellant charges. On new ships from 1891 they were replaced by the rapid fire cannon QF 6 inch .

history

The muzzle loaders with rifled barrel ( RML - Rifle Muzzle Loading) introduced from the mid-1860s had basically proven themselves in the Royal Navy and coastal artillery. Suitable caliber sizes had been determined in lengthy series of tests. However, progress in shipbuilding, particularly with regard to the speed and armor of steam-powered warships, required greater range and cadence as well as greater penetration. When gas-tight closures became available, the breech loader was used again. For economic reasons, however, the large numbers of black powder propellant charges should continue to be used.

construction

The Mk II, III, IV and VI version series was developed by the Royal Gun Factory , but also built by the Elswick Ordnance Company . The bullet weight was originally 80 lb.

Mark II

A bullet weight of 100 lb was introduced with the Mk II version. This was the standard size of British 6-inch breech loaders until 1930.

The soul tube was made of steel and was thicker. The jacket pipe consisted of shrunk rings made of iron. The weight was 9072 lb. However, the cannon was designed too weakly. Therefore, five more rings, this time made of steel, were added to reinforce it. The cannon had to be shortened by 12 inches to maintain balance. The weight was now 9,968 pounds. After a gunfire on the HMS Cordelia in June 1891, these cannons were only used for gun drill.

Mark III, IV, VI

An all-steel construction was introduced with the Mk III version. Both the core tube and the closure part and the elements of the jacket tube were made of steel. The weight of the guns remained at 9,968 lb. When the Mk III was introduced, however, it was limited to weak propellant charges, so the projectiles only achieved a low muzzle velocity. Therefore, the casing tubes were reinforced again in most of the guns. This allowed the propellant charge to be increased to 48 lb, and the muzzle velocity increased to 597 m / s. The weight increased to 5 tons.

The Mk IV took over the subsequent improvements of the Mk III in series production. In the Mk VI version, some construction details have been simplified.

The Mk III, IV and VI versions were the most common. Their wide use shows their general usefulness. Cannons of this series were interchangeable and had the same shooting performance. In summary, they have been referred to as the "6-in-5-ton BLR" in contemporary publications such as Brassey's Naval Annual.

Mark V

→ Main article: BL 6 inch gun Mk V

The Mk V version was an export variant developed by Elswick Ordnance.

QFC conversion

From 1885 many ship guns were converted to the use of cartridged ammunition, as used in the modern rapid fire guns QF 6 inch . These guns were given the designation QFC (QF Converted). The versions have been renumbered and placed in front of the old version number. For example, I / IV indicates the first converted version of an original Mk IV, II / VI indicates the second conversion version for an original version VI.

  • Mk II

  • Mk III with additional reinforcement of the jacket tube

  • Mk IV

  • Mk VI

  • Mks III, IV and VI closure

Ship gun

6-inch gun on the HMS Cossack

The type was used on the following British warships:

Coastal defense

Mk IV or VI on Elswick mounting in production at the Royal Carriage Factory, Woolwich, 1890s
Mk IV or VI gun on Vavasseur mount Mk I, Rabaul, circa 1918

The Mk IV and VI versions were widely used in the coastal defense of the British Empire . They were either mounted on hydropneumatic articulated mounts or had a Vavasseur slide . The upper mount, which is firmly connected to the cannon, slid on an inclined slideway of the lower mount in order to absorb the recoil of the cannon.

In a small part of the guns in the Mk IV and Mk VI versions, the original bolt was replaced by a modern single-motion bolt from 1902. The chamber has been lengthened to accommodate a larger propellant charge. These cannons were called BLC (breech loading converted). With a retrofitted propellant charge of 9.1 kg, they reached a range of 11,000 m. They were replaced by modern 6-inch Mk VIIs as they became available and retired in 1922.

BLC siege cannon

The Mk IV and VI were also used as semi-mobile siege cannons from 1902. The gun and siege mount were transported separately. The gun carriage was assembled in the firing position and the cannon was then mounted. At the outbreak of the First World War, two batteries of these siege cannons were fitted with simple self-propelled wheelers and moved to France as heavy field cannons. It was driven by steam engines. The guns had a simple barrel brake, consisting of two hydraulic cylinders, to absorb the recoil. However, the wheels had to be additionally set when firing. The firing range was around 13,000 m. From 1915 they were quickly replaced by the more modern 6 inch Mk VII .

Conversion to an 8 inch howitzer

→ Main article: BL 8 inch Howitzer Mk I – V

8 inch field howitzer

At the beginning of the First World War there was a lack of heavy field artillery in Great Britain. Therefore, in 1915, the barrel of old 6-inch cannons was drilled open and shortened. These guns were referred to as BL 8 inch howitzers .:

  • 12 BLC Mk I / IV were added to 8-inch howitzer Mk I converted
  • 6 BL Mk IV and VI were added to 8-inch howitzer Mk II converted
  • 6 BL MK IV and VI, respectively , with different Lafettierungen were to 8-inch howitzer Mk III converted
  • 8 BLC Mk I / VI converted for the Mk IV MOUNTINGS were 8-inch howitzer Mk IV converted

literature

Web links

Commons : BL 6 inch Mk II, III, IV, VI naval guns  - Collection of images, videos and audio files

Individual evidence

  1. ^ Text Book of Gunnery, 1902, Table XII p. 336
  2. ↑ Since a conversion into the metric system results in "crooked" values, some of which no longer harmonize with the names of the guns and ammunition, the original units of measurement are used in the text for masses and weights.
  3. ^ Hogg & Thurston, 1972, p. 139
  4. ^ Hogg & Thurston, 1972, p. 142
  5. ^ Hogg & Thurston, 1972, p. 152