BL 5-inch gun Mk I – V
# BL 5-inch gun Mk I – V

The BL 5-inch guns Mk I – Mk V were early British 5-inch rifled breechloading naval guns after it switched from rifled muzzle-loaders in the late 1870s. They were originally designed to use the old gunpowder propellants. The 5-inch calibre was soon discontinued in favour of QF 4.7-inch.

## Naval service

Guns equipped the following British warships :

* Mariner-class gunvessels of 1883
* Satellite-class sloops of 1883
* Comus-class corvettes as re-gunned in the 1880s
* Nymphe-class sloops laid down in 1885
* Calypso-class third class cruiser/corvettes of 1883–1884
* Iris-class cruisers as re-gunned in 1888
* Beagle-class sloops of 1889
* Bacchante-class corvettes as re-gunned in the 1880s

These guns also equipped several small gunboats of Colonial navies of Australia in the 1880s in response to the perceived threat of Russian expansionism in the Pacific (The "Russian scares").

## Second Boer War (1899–1902) field gun

A number of guns mounted on carriages from obsolete RML 40 pounder guns accompanied the British siege train (heavy artillery) to South Africa. They were not required for the expected siege of Pretoria, which did not eventuate. Its usefulness in the field was limited by lack of a recoil control system, and the QF 4.7-inch gun was the most commonly used British heavy gun in the war.

## Coast defence gun

The gun was installed as a conventional coast defence gun in South Africa and Australia, and several in the United Kingdom. Its more common use ashore in the UK was as "moveable armaments" in forts: on 2-wheeled carriages similar to field carriages but intended only for moving short distances to position guns for defence of the fort. These used either obsolete 40-pounder RML carriages or special high-mounting carriages for firing over parapets with recoil controlled by a hydraulic buffer built into the platform to which the carriage was fastened. A number were also set up in practise batteries adjacent to fortifications and batteries.

## Ammunition

* 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

The gun was designed to fire a number of different types of projectile. Common shell could be used against earthworks, buildings and other vehicles and artillery. Shrapnel shell was designed for use against soft targets, such as troops or cavalry, at longer ranges – for soft targets within 400 yards case shot could be used. Palliser shot was designed for use against hard targets, such as enemy ships, where it could penetrate armour plate.

Initially, the gun used black powder propellant, but this was changed for Cordite propellant in the 1890s. Similarly, the black powder filling for common shells was changed for the much more powerful Lyddite filling, which increased the effect of the shell.

