BL 5-inch gun Mk I – V facts for kids

Quick facts for kids Ordnance BL 5-inch gun Mks I – V
Mk I coast defence gun outside entrance to the Hong Kong Museum of Coastal Defence
Type	Naval gun Coast defence gun Field gun
Service history
In service	1880–1947?
Used by	United Kingdom
Wars	Second Boer War
Production history
Variants	Mks I – V
Specifications
Mass	Mk I – II  : 38 long hundredweight (1,930 kg) Mk III – V : 40 long hundredweight (2,030 kg)
Barrel length	125 inches (3,175 mm) bore (25 calibres)
Shell	50 pounds (22.68 kg)
Calibre	5-inch (127.0 mm)
Breech	de Bange
Muzzle velocity	1,750 feet per second (533 m/s)
Maximum firing range	8,700 yards (8,000 m)

The BL 5-inch guns Mk I – Mk V were a series of early British naval guns. These cannons were developed in the late 1870s. At this time, the British Navy was switching from older "muzzle-loading" guns to newer "breech-loading" ones.

Muzzle-loading guns were loaded from the front of the barrel. Breech-loading guns, like these 5-inch models, were loaded from the back. This made them faster and safer to reload. These guns were first designed to use old-style gunpowder. However, the 5-inch size was soon replaced by a slightly smaller, faster-firing gun, the QF 4.7-inch Gun Mk I–IV.

Naval Service: Guns on Warships

Working a starboard broadside gun on Vavasseur recoil mounting on HMS Calliope

These 5-inch guns were used on many British warships. They were an important part of the navy's firepower. These guns were fitted on various types of ships, including:

• Mariner-class gunvessels (small warships) from 1883.
• Satellite-class sloops (another type of small warship) from 1883.
• Comus-class corvettes (medium-sized warships) after they were updated in the 1880s.
• Nymphe-class sloops, which were built starting in 1885.
• Calypso-class third-class cruisers/corvettes from 1883–1884.
• Iris-class cruisers after they were updated in 1888.
• Beagle-class sloops from 1889.
• Bacchante-class corvettes after they were updated in the 1880s.

The guns were also used by smaller navies in Australia. This happened in the 1880s. It was due to worries about Russia expanding its power in the Pacific Ocean. These concerns were sometimes called "Russian scares."

Second Boer War: Field Guns

In South Africa, circa. 1900

During the Second Boer War (1899–1902), some of these 5-inch guns were used on land. They were put on carriages from older RML 40 pounder guns. These guns traveled with the British "siege train." A siege train was a group of very heavy artillery used to attack fortified places.

The British expected to lay siege to Pretoria, a city in South Africa. However, this siege did not happen. The 5-inch guns were not very useful in the open field. This was because they lacked a good system to control their recoil. Recoil is the backward kick of a gun when it fires. The QF 4.7-inch gun was more commonly used by the British in this war.

Coast Defence Guns

Gun on Fortress mount in UK, c1900

The 5-inch guns were also used to defend coastlines. They were set up in South Africa, Australia, and the United Kingdom. These guns were placed in fixed positions to protect harbors and shorelines from enemy ships.

In the UK, they were often used as "moveable armaments" in forts. This meant they could be moved short distances within a fort. They used special carriages for this. These carriages allowed the guns to fire over protective walls called parapets. A hydraulic buffer helped control the gun's recoil. Some guns were also used for practice at gunnery schools.

Ammunition Used

• 

  Mk III and IV shrapnel shells
• 

  BL 5-inch common lyddite shell Mk VIII diagram
• 

  BL 5-inch gun 4lb 7.5 oz cordite cartridge Mark III diagrams

These 5-inch guns could fire different types of shells. Each shell was designed for a specific purpose:

• Common shell: Used against targets like earthworks, buildings, or other artillery.
• Shrapnel shell: Designed to explode in the air and spray metal balls. This was effective against groups of soldiers or cavalry at longer distances. For closer targets (within 400 yards), "case shot" was used, which was similar but for very short range.
• Palliser shot: A special type of shell designed to break through thick armor. It was used against enemy warships.

At first, the guns used black powder as propellant. This is the explosive that pushes the shell out of the gun. In the 1890s, they switched to a more modern propellant called Cordite. Also, the common shells were initially filled with black powder. Later, they were filled with Lyddite, a much more powerful explosive. This made the shells more destructive.

See also

• List of naval guns

Surviving Examples

One of two guns outside the Union Buildings, Pretoria, South Africa

You can still see some of these old 5-inch guns today:

• One gun is on the deck of HMS Gannet in Chatham, UK.
• Two guns are on display outside the Union Buildings in Pretoria, South Africa. They are mounted on old 40-pounder field carriages.
• One gun is outside the entrance to the Hong Kong Museum of Coastal Defence.
• Two guns are outside the old gunnery offices at HMAS Cerberus. This is a Royal Australian Navy training base near Melbourne, Australia.
• Gun No. 479 is on a Vavasseur mount at Queens Park, Maryborough, Queensland, Australia. You can see a picture of it here.
• Another gun on a Vavasseur mount is at The Esplanade, Cairns, Queensland, Australia. You can see a picture of it here.
• A gun on a Vavasseur mount is also at the Maritime Museum of Townsville, Queensland, Australia. You can find more information here.