The BL 6-inch 80-pounder gun Mk I was the first generation of British 6-inch breechloading naval gun after it switched from muzzle-loaders in 1880. They were originally designed to use the old gunpowder propellants.
Mk I of 80 cwt (4 tons) as originally built was an Elswick Ordnance design which was weakly made and fired only an 80-pound (36kg) projectile. It consisted of a steel barrel with wrought-iron coils shrunk over it. A few guns were issued to the Royal Navy but most were replaced by the later versions. Mk I guns remaining in British service were rebuilt with "chase hoops" added around the barrel for strengthening, and the barrel was shortened by 3inches to keep its centre of gravity at the trunnions. This resulted in the 81 cwt Mk I gun.[4]
The breech was rotated to the left to lock it, unlike standard British service BL guns made by the Royal Gun Factory which all rotated to the right to lock.
These guns are commonly referred to as "6-in. 81-cwt B.L.R." in contemporaneous publications such as Brassey's Naval Annual. The official designation in British ordnance manuals was "80-pounder BL" to differentiate it and its ammunition from the later marks of 6-inch BL guns which fired 100-pound projectiles.
80-pounder in Australian colonial service
Quarterdeck of Protector with aft 6-inch gun trained to port, circa. 1903
Australian colonies and New Zealand purchased various 6-inch guns direct from the manufacturers, usually Elswick Ordnance Company, and these versions do not correspond directly with the official "Marks" as adopted by the British government. Specifications of guns purchased by Australian colonies are similar to those of the original British Mk I 80 cwt gun, firing an 80-pound projectile.[5]
The gun equipped some gunboats of the Australian colonial navies:
A restored gun from HMAS Protector is outside the Naval Reserve Cadets building in Jenkins Street, Birkenhead, Adelaide[9]
The aft gun from HMQS Paluma is in the Treloar Centre at the Australian War Memorial, in Canberra
Notes and references
↑ 80 cwt as originally made; 81 cwt includes additional weight of hoops added to strengthen the guns. Treatise on Service Ordnance 1893; Text Book of Gunnery 1902
↑ Treatise on Service Ordnance, 1893, pages 257–265
↑ The Victorian Navy manuals of 1887, 1890 and 1895 quote an 80 cwt gun with a bore 156 inches, firing an 80-pound projectile (Shrapnel), 78lb 7oz (Palliser), 75lb (Common) or 77lb (segment) with muzzle velocity of 1880 ft/sec, using a 42-pound Pebble (gunpowder) "Full" or 30lb Pebble "Reduced" charge, which matches the Mk I gun specifications. Some tables in these manuals refer to the 42-pound charge as a "Battering" charge and the 30-pound charge as "Full" charge. Maximum range of 7,200 yards at 13° 5" elevation firing an 80-pound projectile with a 42-pound gunpowder charge.
This article explains terms used for the British Armed Forces' ordnance and also ammunition. The terms may have slightly different meanings in the military of other countries.
The Armstrong RBL 7-inch gun, also known as the 110-pounder, was an early attempt to use William Armstrong's new and innovative rifled breechloading mechanism for heavy rifled guns.
The QF 12-pounder 12-cwt gun was a common, versatile 3-inch (76.2 mm) calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick and used on Royal Navy warships, exported to allied countries, and used for land service. In British service "12-pounder" was the rounded value of the projectile weight, and "12 cwt (hundredweight)" was the weight of the barrel and breech, to differentiate it from other "12-pounder" guns.
The QF 14-pounder was a 3-inch medium-velocity naval gun used to equip warships for defence against torpedo boats. It was produced for export by Maxim-Nordenfelt in competition with the Elswick QF 12-pounder 12 cwt and QF 12-pounder 18 cwt guns.
The QF 6 pounder Nordenfelt was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries.
The Ordnance BL 12-pounder 7cwt was the British Army's field gun, which succeed the RML 13-pounder 8 cwt in 1885.
The BL 9.2-inch Mk I–VII guns were a family of early British heavy breechloading naval and coast defence guns in service from 1881 to the end of World War I. They were originally designed to use the old gunpowder propellants.
The BL 6-inch gun Marks II, III, IV and VI were the second and subsequent generations of British 6-inch rifled breechloading naval guns, designed by the Royal Gun Factory in the 1880s following the first 6-inch breechloader, the relatively unsuccessful BL 6-inch 80-pounder gun designed by Elswick Ordnance. They were originally designed to use the old gunpowder propellants but from the mid-1890s onwards were adapted to use the new cordite propellant. They were superseded on new warships by the QF 6-inch gun from 1891.
The BL 10 inch guns Mks I, II, III, IV were British rifled breechloading 32-calibre naval and coast defence guns in service from 1885.
The BL 8 inch guns Mark I to Mark VII were the first generations of British rifled breechloaders of medium-heavy calibre. They were initially designed for gunpowder propellants and were of both 25.5 and 30 calibres lengths.
The BL 4-inch gun Mk I – Mk VI were a family of early British breech-loading 4-inch naval guns.
The BL 6 inch gun Mk V was an early Elswick Ordnance Company breech-loading naval gun originally designed to use the old gunpowder propellants. They were used for coast defence around the British Empire.
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.
The Armstrong RBL 40-pounder gun was introduced into use in 1860 for service on both land and sea. It used William Armstrong's new and innovative rifled breechloading mechanism. It remained in use until 1902 when replaced by more modern Breech Loading (BL) guns.
The Armstrong Breech Loading 20-pounder gun, later known as RBL 20-pounder, was an early modern 3.75-inch rifled breech-loading light gun of 1859.
The RML 64-pounder 64 cwt gun was a Rifled, Muzzle Loading (RML) naval, field or fortification artillery gun manufactured in England in the 19th century, which fired a projectile weighing approximately 64 pounds (29 kg). "64 cwt" refers to the gun's weight rounded up to differentiate it from other "64-pounder" guns.
The RML 10-inch guns Mk I – Mk II were large rifled muzzle-loading guns designed for British battleships and monitors in the 1860s to 1880s. They were also fitted to the Bouncer and Ant-class flat-iron gunboats. They were also used for fixed coastal defences around the United Kingdom and around the British Empire until the early years of the 20th century.
The RML 9-inch guns Mark I – Mark VI were large rifled muzzle-loading guns of the 1860s used as primary armament on smaller British ironclad battleships and secondary armament on larger battleships, and also ashore for coast defence. It should not be confused with the RML 9-inch Armstrong Gun, used by the Dutch navy, the Spanish Navy, and other navies.
The RML 12.5-inch guns were large rifled muzzle-loading guns designed for British battleships and were also employed for coast defence.
The RML 7-inch guns were various designs of medium-sized rifled muzzle-loading guns used to arm small to medium-sized British warships in the late 19th century, and some were used ashore for coast defence.
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