7 ton: 1,561 feet per second (476m/s) 6½ ton: 1,525 feet per second (465m/s) 90 cwt: 1,325 feet per second (404m/s)
Maximumfiringrange
5,500 yards (5,000m)
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.
These guns were the first to incorporate the new "Woolwich" rifling system, a modification of the French system, of from 3 – 9 broad shallow grooves after Britain abandoned the Armstrong "shunt" rifling system in May 1865: "...M.L. 7in (18cm) guns in course of manufacture were rifled on this principle, upon which all of our heavy pieces since have been rifled. The 7in (18cm) referred to, and introduced into the service in 1865, were the first of the so-called Woolwich guns, which then meant "wrought iron M.L. guns built up on Sir W. Armstrong's principle, improved upon by hooking the coils over one another, and having solid ended steel barrels, rifled on the system shown above, for studded projectiles".[4]
All versions were constructed of a steel A tube surrounded by various numbers and thicknesses of wrought-iron coils. Rifling was 3 grooves with a uniform 1 turn in 35 calibres i.e. in 245in (620cm).[2]
The diagrams below show the progression from the original expensive Armstrong construction in Mk I of multiple relatively thin coils, through to the simplified and cheaper Woolwich design of Mk III.
The 4 Marks of 7 ton gun
The 3 Marks of 6½ ton gun
90 cwt gun
RML 7-inch 7 ton gun
Remains of a 7-ton Mk III gun on Flat Holm island, UK
This was a coast defence gun introduced in 1865 to replace the failed RBL 7-inch Armstrong gun.Three marks were produced.
RML 7-inch 6½ ton gun
This was a naval gun introduced in 1865 "...as a broadside or pivot gun for frigates, to replace the 7-inch B.L. and 68-pr S.B. guns, and is now very extensively used, 331 having been made... These guns are in total length 18in (46cm) shorter than the land service [i.e. 7-ton] 7in (18cm) gun, being a length more suited to the requirements of the Navy".[5] Some sources credit these weapons with the ability to pierce up to 7.7 inches (196mm) of armour.[6]
This was a lighter (90 cwt = 4½ tons) low-powered naval gun introduced in 1874 as a broadside gun on unarmoured vessels, and not intended for attacking armour plate. Early models were made by simply turning off some of the jacket around 7in (18cm) 6½ ton guns, as firing with reduced charges placed less strain on the coils. Some new guns were made to similar design.
The primary projectile for 7 ton and 6½ ton guns was Palliser shot or shell for attacking armoured warships, fired with a large "battering" charge for maximum velocity. All guns were also equipped with shrapnel shells for anti-personnel use and explosive common shells for attacking unarmoured targets. The "double" common shell was much longer than the standard common shell, and hence contained approximately twice as much gunpowder. It was unstable in flight and hence inaccurate beyond 2,000yd (1.8km) but was considered useful for attacking wooden warships at ranges below 2,000yd (1.8km).[7]
↑ Unit cost of £424 11 shillings 10 pence is quoted for the 7-inch 6½ ton gun in "The British Navy" Volume II, 1882, by Sir Thomas Brassey. Page 38
1 2 Treatise on construction of ordnance in the British service, 1877, Table XXIX
↑ Treatise on Ammunition 1877 and Treatise on construction of ordnance in the British service, 1877 describe a 115-pound projectile; Text Book of Gunnery 1887 and Brassey's Naval Annual 1888 describe a 112-pound 1 oz projectile. 112 lb 1 oz appears to be the weight of the empty Palliser shell i.e. without gunpowder filling which was typically 2 lb 10 oz. By 1887 palliser shell had been discontinued and existing shell converted to shot by removing the gunpowder – hence old Palliser ammunition would then be 112 lb 1 oz.
↑ Treatise on construction of ordnance in the British service, 1877, Page 91
↑ Treatise on construction of ordnance in the British service, 1877, Page 269
↑ Conway's All the World's Fighting Ships 1860-1905, 1979, Page 9
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.
A muzzle-loading rifle is a muzzle-loaded small arm or artillery piece that has a rifled barrel rather than a smoothbore. The term "rifled muzzle loader" typically is used to describe a type of artillery piece, although it is technically accurate for small arms as well. A shoulder arm is typically just called a "rifle", as almost all small arms were rifled by the time breechloading became prevalent. Muzzle and breechloading artillery served together for several decades, making a clear distinction more important. In the case of artillery, the abbreviation "RML" is often prefixed to the guns designation; a Rifled breech loader would be "RBL", or often just "BL", since smoothbore breechloading artillery is almost nonexistent. A muzzle loading weapon is loaded through the muzzle, or front of the barrel. This is the opposite of a breech-loading weapon or rifled breechloader (RBL), which is loaded from the breech-end of the barrel. The rifling grooves cut on the inside of the barrel cause the projectile to spin rapidly in flight, giving it greater stability and hence range and accuracy than smoothbore guns. Hand held rifles were well-developed by the 1740s. A popularly recognizable form of the "muzzleloader" is the Kentucky Rifle, which was actually developed in Pennsylvania. The American Longrifle evolved from the German "Jäger" rifle.
The 100-ton gun was a 17.72 inches (450 mm) rifled muzzle-loading (RML) gun made by Elswick Ordnance Company, the armaments division of the British manufacturing company Armstrong Whitworth, owned by William Armstrong. The 15 guns Armstrong made were used to arm two Italian battleships and, to counter these, British fortifications at Malta and Gibraltar.
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 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 RML 64-pounder 64 cwt gun is 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 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.
RML 16-inch 80-ton guns were large rifled muzzle-loading guns intended to give the largest British battleships parity with the large guns being mounted by Italian and French ships in the Mediterranean Sea in the 1870s.
The RML 12-inch 25-ton guns were large rifled muzzle-loading guns of mid-late 1800s used as primary armament on British ironclad turret battleships and coastal monitors, and also ashore for coast defence. They were the shorter and less powerful of the two 12-inch (305-mm) British RML guns, the other being the 35-ton gun.
RML 12-inch 35-ton guns were large rifled muzzle-loading guns used as primary armament on British battleships of the 1870s. They were the longer and more powerful of the two 12-inch British RML guns, the other being the 25-ton gun.
RML 11-inch 25-ton guns were large rifled muzzle-loading guns used as primary armament on British battleships and for coastal defence. They were effectively the same gun as the RML 12-inch 25-ton gun, bored to 11 inches instead of 12.
The 68-pounder cannon was an artillery piece designed and used by the British Armed Forces in the mid-19th century. The cannon was a smoothbore muzzle-loading gun manufactured in several weights, the most common being 95 long cwt (4,800 kg), and fired projectiles of 68 lb (31 kg). Colonel William Dundas designed the 112 cwt version in 1841 and it was cast the following year. The most common variant, weighing 95 cwt, dates from 1846. It entered service with the Royal Artillery and the Royal Navy and saw active service with both arms during the Crimean War. Over 2,000 were made and it gained a reputation as the finest smoothbore cannon ever made.
The British RML 8-inch 9-ton guns Mark I – Mark III were medium rifled muzzle-loading guns used to arm smaller ironclad warships and coast defence batteries in the later 19th century.
The RML 40-pounder gun was a British rifled muzzle-loading siege and fortification gun designed in 1871. It was intended to supersede the RBL 40-pounder Armstrong gun after the British military reverted to rifled muzzle-loading artillery until a more satisfactory breech-loading system than that of the Armstrong guns was developed.
Gas-checks were attachments to ammunition that revolutionised the performance of RML heavy guns. The first generation of RML heavy guns began entering service in about 1865. They all had Woolwich rifling and relied on studs on the projectiles for rotation. Gas-checks were first introduced in 1878 or soon after. They significantly reduced wear on the guns while also increasing their range and accuracy. Before long, studless ammunition was being manufactured for these guns, using gas-checks for projectile rotation. Gas-checks also facilitated a switch to the second generation of RML guns which used polygroove rifling and only supported studless ammunition.
The RML 9-inch Armstrong Gun was a rifled muzzle loading gun, used in substantial numbers by the Dutch navy, the Spanish Navy, and other navies. It should not be confused with the RML 9-inch 12-ton gun, used in the British Royal Navy.
The RML 7-inch Armstrong Gun was a rifled muzzle loading gun. It was an export version of the British Royal Navy's RML 7-inch gun. The RML 7-inch Armstrong Gun was produced by William Armstrong's Elswick Ordnance Company.
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