Armstrong Gun

The Armstrong gun as a breech-loading field-piece first attracted attention in England about 1850. About 1858 it was adopted by the British government. This gun was made of wrought iron, and consisted of a single coiled tube reinforced at the breech with two thin tubes, the outer one being a coiled tube, the inner being formed by bending a plate and welding the edges. The coiled tubes were formed by bending square bars of iron around a mandrel and welding the coils together. Tubes made in this way offer great resistance to tangential strains. The intermediate tube was designed to take up the longitudinal strain near the breech, and for this reason was made differently. The breech was closed with a vent-piece, slipped by the band into a slot cut in the piece near the breech, and held in its place by a breech-screw, which supported it from behind. This screw was made in the form of a tube, so that its hollow formed a part of the bore prolonged, when the vent-piece was drawn. Through the hollow screw the charge was pa ed into the chamber. The vent was formed in the breech-piece. This gun was a 3-inch 12-pounder, firing a lead-coated projectile. It was followed by the 40-pounder, 110-pounder, and other calibres. Muzzle-loaders were also made. The breech-loading apparatus did not prove entirely succe ful in large guns, and was accordingly discarded except for small calibres. The method of construction was changed for larger guns, and a plan adopted which has been adhered to ever since, and is that now used. The barrel or part surrounding the bore is made of steel tempered in oil; that portion at and in rear of the trunnions is enveloped by several layers of wrought-iron tubes, the number of layers depending upon the size of the gun. These tubes, instead of being joined at their ends by welding, are hooked on to each other by a system of shoulders and rece es. There are also projections fitting into corresponding rece es, which serve to prevent the tubes from slipping within each other. The tube which immediately surrounds the barrel opposite to the seat of the charge is called the breech-piece. It is made with its fibres and welds running longitudinally, so as to resist the recoil of the barrel against the head of the breech-plug, which is screwed into the breech-piece. The shunt system of rifling was first applied to muzzle-loading Armstrong guns, which have fewer grooves than the breech-loaders. The method of manufacturing originally proposed by Sir William Armstrong has been greatly modified by Mr. Fraser, of the Royal Arsenal, Woolwich. (See Ordnance, Armstrong Cannon ). For some years large numbers of Armstrong guns were made at the Royal Arsenal, Woolwich, under the supervision of the inventor. His works are now located at Elswick, Newcastle-upon-Tyne, and are known us the Elswick Ordnance Works. To distinguish the system of gun-construction from the “Woolwich,” which it closely resembles, it is frequently called the “Elswick” system. The largest, as well as the most powerful guns ever made, are the 100-ton guns manufactured at Elswick for the Italian navy. See Cannon and Ordnance, Modern History of .