BL 5 inch Mk I – V gun

• Name — Ordnance BL 5-inch gun Mks I – V • Type — Naval gun Coast defence gun Field gun • Is Ranged — YES • Is Artillery — YES • Is Uk — YES • Service — 1880–1947? • Used By — United Kingdom • Wars — Second Boer War • Variants — Mks I – V • Weight — Mk I – II: 38 long cwt Mk III – V: 40 long cwt • Part Length — 125 in bore (25 calibres) • Cartridge — 50 lb • Caliber — 5 in • Velocity — 1750 ft/s • Max Range — 8700 yd • Breech — de Bange

• Illustration — Working a starboard broadside gun on Vavasseur recoil mounting on HMS Calliope Guns equipped the following British warships: • s of 1883 • s of 1883 • s as re-gunned in the 1880s • s laid down in 1885 • third class cruiser/corvettes of 1883–1884 • s as re-gunned in 1888 • s of 1889 • s 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").

• Illustration — In South Africa, circa. 1900 • Illustration — 5-inch Armstrong Mark II 40-pounder rifled undercarriage, War Museum, Bloemfontein, South Africa, 2025. 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.

• Illustration — Gun on Fortress mount in UK, c1900 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.

• Illustration — Mk III and IV shrapnel shells • Illustration — BL 5-inch common lyddite shell Mk VIII diagram • Illustration — 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.

• Illustration — One of two guns outside the Union Buildings, Pretoria, South Africa • A gun on the deck of HMS Gannet, Chatham, UK. • 2 guns on 40-pounder RML field carriages, outside the Union Buildings, Pretoria, South Africa • Outside the entrance to the Hong Kong Museum of Coastal Defence • Two guns outside the old school gunnery offices at HMAS Cerberus, Royal Australian Navy training base south of Melbourne, Victoria, Australia • No. 479 on Vavasseur mount at Queens Park, Maryborough, Queensland, Australia, • A gun on Vavasseur mount at The Esplanade, Cairns, Queensland, Australia • A gun on Vavasseur mount at the Maritime Museum of Townsville, Queensland, Australia • A 5-inch Armstrong Mark II 40-pounder rifled undercarriage, standing at the Anglo Boer War Museum, Bloemfontein, South Africa, 2025.