Armstrong gun
The Armstrong Gun is a type of large rifled gun first manufactured in England in 1855. It was designed by Sir William Armstrong and manufactured by the Elswick Ordnance Company and the Royal Arsenal at Woolwich.
History
In 1854 Armstrong approached the Secretary of State for War, proposing that he construct a rifled breech-loading 3-pounder gun for trial. Later increased in bore to 5-pounder, the design performed successfully with respect to both range and accuracy. Over the next three years he developed his system of construction and adapted it to guns of heavier calibre.
Armstrong's system was adopted in 1858, initially for "special service in the field" and initially he only produced smaller artillery pieces, 6-pounder (2.5 inches (64 mm)) mountain or light field guns, 9-pounder (3 inches (76 mm)) guns for horse artillery, and 12-pounder (3 inches (76 mm)) field guns.
Armstrong did not consider his system suited to heavier guns but higher authorties had him develop a 20-pounder (3.75 inches (95 mm)) field gun, a 40-pounder (3.75 inches (95 mm)) siege gun, and a 110-pounder ((7 inches (180 mm))) heavy gun. The Royal Navy used all these guns and all except the 20-pounder saw service in New Zealand.
Armstrong system
Armstrong's guns were constructed of wrought iron and used a "built-up" construction, comprising a tube holding the bore on to which were shrunk smaller tubes, a breech, trunnion ring. The guns' rifling was on the "polygroove" system; the bore of the gun had 38 grooves along its length with a twist of one turn per 38 calibres. The cast iron shells, were similar in shape to a Minié ball, were coated in lead. This permitted the grooves to bite into the projectiles and impart the required spin.
An innovative feature which is more usually associated with 20th-century guns was what Armstrong called its "grip", which was essentially a squeeze bore; the last 6 inches of the bore at the muzzle end was of slightly smaller diameter, which centered the shell before it left the barrel and at the same time slightly swaged down its lead coating, reducing its diameter and slightly improving its ballistic qualities.
The breech loaders used a vertical sliding block, which had a conical copper-ringed plug which sealed the firing chamber, to close the breech. To hold both block and plug tightly in place the guns used a breech screw.
Armstrong guns in action
The British used Armstrong guns extensively to great effect in the Second Opium War. As reported by the translator Robert Swinhoe, after the British attack on the Chinese fort at Pehtang:
Numbers of dead Chinese lay about the guns, some most fearfully lacerated. The wall afforded very little protection to the Tartar gunners, and it was astonishing how they managed to stand so long against the destructive fire that our Armstrongs poured on them; but I observed, in more instances than one, that the unfortunate creatures had been tied to the guns by the legs."[1]
Return to muzzle-loading guns
In 1863 an Ordnance Select Committee met to consider the merits of muzzle-loading and breech-loading guns. In 1864, even before they had concluded their investigations, the Government stopped the manufacture of Armstrong breech-loaders. When the Committee finally reported, in August 1865, they announced that:
The many-grooved system of rifling with its lead-coated projectiles and complicated breech-loading arrangements is far inferior for the general purpose of war to the muzzle-loading system and has the disadvantage of being more expensive in both original cost and ammunition. Muzzle-loading guns are far superior to breech-loaders in simplicity of construction and efficiency in this respect for active service; they can be loaded and worked with perfect ease and abundant rapidity.
However, their report did admit that Armstrongs' guns, while more expensive, were undoubtedly safer in that while it was not uncommon for cast iron muzzle-loaders to burst (see below), not one Armstong gun had ever done so. (Furthermore, gunners could clear a hangfire from the breech; when the 100-tun gun (see below) at Napier of Magdala Battery hung fire, a gunner had to be lowered head-first down the bore to attach an extractor to the shell.)
Despite a further report which remarked on the advantages of breech-loaders, cost dominated the proceedings and the Committee finally announced that "The balance of advantages is in favour of muzzle-loading field guns" and in 1870 Britain reverted from breech-loading ordnance to muzzle-loading.[2]
To allow rifling to be used with muzzle-loaders, Armstrong proposed in 1866 a new system whereby the shells had studs on the outside, which aligned with grooves in the barrel of the cannon.
100-ton guns
In 1876 Armstrongs offered the British Admiralty a 100.2-ton gun with a bore of 450mm or 17.76in. The Admiralty rejected the design so instead Armstrongs offered manufacturing rights to Italy. The Italians constructed several of the guns and fitted four of them in each of the new battleships Duilio and Dandalo.
The British government, realizing that these Italian warships with their 22 inches (560 mm) of armor would be impervious to Malta's defensive weapons, hastily commissioned guns of even greater caliber of 160-tons and then 220-tons. When it became apparent that these specifications were beyond the capabilities of contemporary manufacturing technology, the British instead ordered four of the 100-ton guns for service at Gibraltar and Malta.
In Gibraltar, they installed one at Victoria Battery and one at Napier of Magdala Battery. At Valetta in Malta, they installed one at Sliema (Fort Cambridge) to the north of the harbor and one at Kalkara (Fort Rinella) to the east of the harbor. To house the Maltese guns the British used purpose-built forts that each cost £18,890 to construct.
While they had ordered their guns first, the Italians did not receive their guns until after the British Navy had installed theirs. One of the guns on the "Duilio' burst at Spezia in 1880, as did the gun at Victoria Battery. Two of the British guns survive to the present, the one at Napier of Magdala Battery and the one at Fort Rinella.
Description
Each gun weighed 100.2 long tons (101.8 t), had a barrel 30 feet 3 inches (9.22 m) long and a bore of 17.72 inches (450 mm). The bulk of the bore, 30 feet 3 inches (9.22 m), was rifled, greatly increasing the accuracy of the gun relative to smoothbores. A powder charge of 450 pounds (204.117 kg)* of prism black powder could propel a 450 pounds (204.117 kg)* shell up to 8 miles (13 km). The muzzle velocity was 1,540 feet (469.392 m)* per second (approx. 1,200 miles per hour (1,900 km/h)), and the shell could penetrate 24.9 inches (630 mm) of iron. Even so, the Italian government conducted tests in 1876 using its own 100-ton guns that proved that the 22 inch armor of its battleships would be able to withstand the guns.
At Fort Rinella the battery was crewed by a battery commander and a master gunner, with nine gunners. Twelve men dealt with the ammunition, three the rangefinder, while there were also a trumpeter, a storeman, a lampman and a fatigue[disambiguation needed] man. A telephonist maintained communications with the other battery at Fort Cambridge and a control station at Fort St. Elmo. If the telephone line was damaged, there was a backup semaphore and heliograph. It was intended that one gun should fire while the other was reloading, with a rate of fire of one round every four minutes; an attempt was made at Gibraltar to increase the rate of fire which ended up with one of the guns splitting its barrel.[3]
To enable the crew to load and traverse the massive gun, each had a steam engine which fed high-pressure steam to a hydraulic accumulator. It took 3 hours to generate the required head of steam from cold. The 100-ton guns were the largest muzzle loading guns ever built. Not long after their manufacture and installation engineers designed new breech loading systems that made the muzzle loaders obsolete.
See also
Notes
- ^ Robert Swinhoe, Narrative of the North China Campaign of 1860 (London: Smith, Elder & Co, 1861) p. 105.
- ^ Ruffell, WL. "The Gun - Rifled Ordnance: Whitworth". The Gun. Retrieved 2008-02-06.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help) - ^ Farrugia, Mario (2006). Fort Rinella and Its Armstrong 100-Ton Gun. Midsea Books. ISBN 9993239909.
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Further reading
- Jack Beeching, The Chinese Opium Wars (1975), ISBN 0-15-617094-9
- Erik Ringmar, Fury of the Europeans: Liberal Barbarism and the Destruction of the Emperor's Summer Palace
External links
