The Development of Navies During the Last Half-Century/Chapter 9
Old Smooth Bore Guns and their Manipulation—Mr Lancaster's System—Introduction of Rifled Guns—Early Inventors—Breech-Loaders introduced and discarded—Woolwich Muzzle-Loaders—Growth of Ordnance to 8o-ton Guns—Breech-Loaders again introduced—Increase of Length and Power — Advance to no-ton Guns—Ammunition—Quick-Firing Guns.
These guns were naturally very inaccurate, and could not be otherwise, independently of the rude methods for directing their fire. In the first place, the bore was considerably larger than the shot, to facilitate loading and the use of red-hot shot. This difference of diameter was called 'windage,' and varied from one-fifth to one-third of an inch. It allowed, therefore, a considerable portion of the gunpowder gas to escape past the projectile, and wasted so much energy. Then, for reasons which would require too technical an explanation for this work, the round shot was subject to special inaccuracies in its flight. These defects were not so manifest at close quarters in action, which officers in command usually sought to attain, and the charge of powder, however reduced in energy by windage, retained sufficient power to penetrate wooden ships. But for some years previous to the substitution of ironclads for the old types of ships the Admiralty of this country had been impressed with the advantages of having the armament of the navy of greatly increased power and weight. This view was confirmed by the introduction of the 68-pounder, which proved a powerful and effective weapon. But when it had been ascertained that this gun was powerless against 4½-in. plates, it was at once evident that some new system of gun construction must be devised. A long series of experiments proved that the old ordnance was exceedingly defective; that every gun, great or small, should be rifled, in order to give long range and precision to the projectile; and that to have the required strength guns must be made of wrought-iron or steel.
The object of a rifled gun is to give to a cylindrical projectile rotation or spin on its longer axis. The rotatory motion keeps the shot steady during flight, and prevents its being subject to the special influence which caused the inaccuracy of smooth bore guns. A cylindrical projectile is heavier than the round shot of similar diameter. Thus the old 32-pounder was of 6-in. diameter, but the modern 6-in. rifled gun throws a projectile of 100 lbs. weight.
There are other advantages, on which it is unnecessary to dwell, but for many years artillerists had been seeking a satisfactory method of giving rotation to the projectile. One of the earliest inventors in this country was Mr Lancaster, who conceived the idea of making the bore of a gun slightly elliptical or oval, with a twist, so that a projectile of the same shape received a spin during its passage through the bore. Fairly successful experiments resulted in the construction of some of these guns and their employment in the siege of Sebastopol. But they were not reliable, and more than one burst. In the meantime a rifle had been adopted for the army in place of the old smooth bore musket, and it was only a question of working out the principle for larger guns.
In 1846 Major Cavalli, of the Sardinian army, and Baron Wahrendorff, a Swedish noble, had each brought forward a breech-loading rifled gun throwing cylindrical projectiles with pointed heads. Cavalli's gun was of 64-in. calibre, and had two grooves cut spirally along the bore. The projectiles had two winged projections which travelled in the grooves and caused rotation. The breech was closed by an iron wedge entered from the top of the gun. With the usual interval for improvements, experiments were carried out in Italy with this gun, which showed considerable advance in accuracy over the smooth bores.
Wahrendorff's gun was similar in principle, though the details were different. Trials took place at Shoeburyness in 1850 with both the Wahrendorff and Cavalli gun, but the breech mechanism was defective, and neither was adopted. So matters rested until after the Crimean War, when the question was seriously taken up in this country. Able inventors turned their attention to rifled ordnance, and among the foremost were Messrs Armstrong and Whitworth. In fact Mr Armstrong had made a small rifled gun in 1855, and the principle on which this was constructed was eventually adopted. The first had a steel barrel strengthened externally by wrought-iron, applied in a twisted or spiral form as in a fowling piece. This gives the strength due to the fibre of the material being disposed at right angles to the bore. The gun was rifled with numerous small grooves. The projectiles were cylindrical, of cast-iron, and coated with lead, to take the grooves and so receive rotation. Being pushed in from the rear or breech, allowance for windage was unnecessary, as the projectile was only inserted sufficiently far for the lead coating to abut against the beginning of the rifling, and the action of the powder forced the projectile to take the grooves.
Satisfactory results were obtained, and a larger gun was constructed. The steel barrel was abandoned as being untrustworthy, and difficult to manufacture sound. Coiled wrought-iron was used entirely. The breech-closing arrangement was the same as before. This was arranged as follows. The rear of the gun had a hole through it, forming a prolongation of the bore, and by this aperture powder and shot were entered. Then the bore was closed by an iron plug inserted through an opening on the top of the gun. To press it firmly against the end of the barrel, it was tightened in its place by a screw working in the loading aperture. The Government so highly approved of this gun that Mr Armstrong was knighted and given an official appointment at Woolwich. It was certainly a great improvement both in range and accuracy over any preceding weapon. With one of these guns a range of 9000 yards was obtained.
Between 1860 and 1861 we commenced supplying the navy with 20, 40 and 100-pounder Armstrong guns. My first experience of the sea was leaving England in a 50-gun frigate, towards the close of 1861, with several of these guns for distribution among the ships of the North American Squadron. The arrest of Messrs Slidell and Mason had lately occurred, and relations with the United States were rather strained. But the new guns did not reach their destination, for we encountered a tremendous gale of wind off the banks of Newfoundland, and sustained such damage as to necessitate our return to England. Our cargo assisted the elements in our discomfiture, making the ship roll so heavily, and she had this propensity in a less degree at all times, that much of the damage resulted from this cause. We were not sorry, therefore, to see the guns transferred to another vessel, while we went into dock with all the appearance of having taken part in a severe action.
These Armstrong breech-loaders did not, however, remain long in use in the navy. There was an absence of simplicity for which, coming directly after the old smooth bores, the navy was not yet prepared. The advantages of charging at the breech were not sufficiently apparent. It was formerly difficult to make a mistake in handling a gun, but now more care had to be taken. In one of our periodical small wars, which occurred at that time in Japan, some cases occurred of vent pieces being blown out on firing these guns. This was owing, no doubt, to the plugs not being screwed up tightly, but it created a prejudice against a system in which this might occur. Another objection was that the lead coating on the projectile occasionally stripped off when being forced through the grooves. This affected the land service, as such artillery firing over the heads of troops might give them a leaden shower. Anyhow the fiat was issued that a new gun must be devised which should be rifled and load at the muzzle. Was this a retrograde step taken less that thirty years ago, and at a time when other nations had adopted the breech-loading system? I do not think so. At that time all guns were short, and loading at the muzzle was not inconvenient. Their handling was equally expeditious, and simplicity was on the side of the muzzle-loader. This advantage would have been more apparent in war. Our fault was not in reverting to muzzle loading, but in retaining the system after the introduction of slower burning powder, which required a long gun to utilise all its energy. The new combination gave increased velocity, range, and penetration. As is well known, the path of a shot in the air is a curve, owing to the action of gravity. The quicker it is in travelling the less time there is for gravity to act, and consequently the more nearly does the projectile travel in a horizontal line. One of the great objects in gunnery is to have this path—or trajectory, as it is technically termed—as flat as possible. I have mentioned Mr Whitworth as being early in the field as a designer of rifled guns. His system differed from Mr Armstrong's in important respects. It will be sufficient to allude to his method of rifling and the form of his projectiles. The former consisted of a hexagonal bore with a sharp twist. The projectile had six bearing surfaces and accurately fitted the bore. Mr Whitworth advocated flat-headed steel shot for attacking armour; but a pointed head is less impeded by the wind and better suited for penetrating armour.
Captain Blakeley also put forward rifled guns which did not materially differ from Whitworth's construction. Captain Palliser had already turned his attention to utilising our old smooth bores, by inserting an interior barrel of coiled wrought-iron, the gun being previously bored out for its reception. It was then rifled, and a few heavy rounds fired, which expanded the inner barrel to a tight fit with its cast-iron exterior. A 68-pounder was so converted into a 9-in. muzzle-loading rifled gun and subjected to severe tests in 1863. With a charge of 16 lbs. of powder projectiles up to 680 lbs. weight were fired from it. The recoil was naturally violent under such conditions. It smashed carriages, and then the gun was suspended in iron slings. It broke these, however, and flung itself out of them on to the ground, but did not burst. This eventually occurred with 32 lbs. of powder and a 200-lb. shot. The evidence of increased strength given by a coiled iron barrel led to a number of smooth bores being converted in this way and employed until comparatively recently in the navy. A steel barrel was subsequently used.
When it was decided to revert to muzzle-loading for new guns the Woolwich system was adopted. This consisted of a steel barrel with a series of wrought-iron coils shrunk over it by being put on when heated. They thus tightly gripped the inner tube, and enabled it to sustain the explosion of a heavy charge without rupture. The strength of the gun was considered to lie in the outer coils; the steel tube gave a hard surface to the bore and a homogeneous material for the rifling process. This tube was made from a solid ingot of steel, turned and then bored out to the required diameter. It was thus the most costly part of the gun, while the boring and rifling processes required considerable time before the rest of the parts could be added.
In 1865 we began equipping our ships with guns of this construction. As an advance on the 68-pounder a gun of 7-in. calibre and 6½ tons weight was produced. Its projectile was 115 lbs. weight, while the charge was 30 lbs. of powder. The charge of the old 68-pounder was 16 lbs. At 1000 yards there was sufficient energy to penetrate 7 in. of iron. Had armour not increased in thickness, we might have been satisfied with such a capability. But much stouter plates were now being rolled, and the gun had to grow likewise. Ordnance of 9, 12 and 18 tons, all on the principle described, were successively designed and put afloat. The largest of these was charged with 70 lbs. of powder and a projectile weighing 400 lbs. The 9-in. armour of the 'Hercules' had defied the efforts of a 300-pounder, and Sir William Armstrong, in a letter to the Times of June 26th, 1865, said, speaking of a 600-pounder which had then been tried: 'Powerful as this 600-pounder has proved itself to be, I confess I have great doubts of its obtaining the mastery over the "Hercules" target unless the enormous charges already used with that gun be still further increased.' He doubted the possibility of constructing a gun of sufficient strength to penetrate the 'Hercules' target. But hardly had these words been written when heavier guns began to be produced, and we passed on to ordnance of 25 and 35 tons. This was the struggle between guns and armour.
It is not to be supposed that guns of this weight could be carried on board ship without an entire reconstruction of the methods of mounting them. To Captain Scott's iron gun-carriages is due a facility in working these guns which had not in some respects been obtained with the much lighter smooth bore. The same rapidity of loading could not be expected, but a gun could be directed on its object much more expeditiously with cogged wheels and winches than with the old rough method of handspikes and tackles. The gun recoiled up a slide, the extent of the recoil being regulated by friction between carriage and slide. The projectiles, instead of being passed from hand to hand, as in the case of the 32-pounder, were wheeled up in iron trucks to the muzzle and then hoisted by a tackle for insertion. There was still room for the display of strength and activity. We had not arrived at working a lever—as at a railway siding—to actuate a hydraulic ram which would bring up the ammunition, while the movement of another handle ejected a rammer which forced all into its place. By the improved method of mounting already described, and mechanical arrangement for controlling the recoil, we were enabled to work guns weighing 25 tons on the broadside with celerity and safety. Though heavy, such guns were necessarily short. Thus the 12-in. 25-ton gun had a bore only 12 calibres long—the calibre of a piece being the diameter of its bore. As we are now employing ordnance of 25, 30, and 35 calibres, the advance in this respect since 1870 can be realised. But after that date longer and heavier guns were constructed. With the same calibre, 12-in., we proceeded to a 35-ton gun of greater length for the 'Devastation's' turrets. Then a slower burning powder being produced, we found that a 38-ton gun could be made nearly 16 calibres long of 12½-in. bore, which would speed an 800 lb. projectile with an initial velocity of 1540 ft. per second, an increase of 200 ft. per second over the 25-ton gun, while the charge of powder had advanced from 85 to 200 lbs.
The 38-ton gun was justly considered a great step, but its projectile, weighing 800 lbs. had passed beyond manipulation by hand or tackle. Then the ingenuity of the great Elswick firm provided us with that admirable system by which all the operations of loading, elevating, and training heavy guns are performed by hydraulic machinery. To describe these in detail would require a volume in itself. It will be sufficient to state that, on the principle of the 'Bramah' press, power is transmitted from an engine by water pressure through a small pipe actuating hydraulic rams. Water is contained in a tank and pumped by a steam engine into pressure pipes, by which it passes to the different hydraulic machines and then returns to the tank. One of the advantages of this system is that fewer men are required round the gun. To work a turret by hand originally took fifty men, now it is effected by a third of the number. Then there is no such danger as the bursting of a steam pipe would involve. The gun does not require a high carriage, but rests in a block on the slide. The recoil is controlled by a solid ram fixed to this block, which on discharge of the gun travels in a cylinder full of water. The pressure of the ram or piston forces the water through a number of weighted valves, the resistance of which gradually brings the gun to rest. Then forcing water into the cylinder pushes the piston or ram and the gun out again. The same principle is employed to raise the breech and extract the breech piece when too cumbrous to be withdrawn by hand. Objection has been raised that the system is too complex, and that the gun may be disabled by the rupture of a small pipe. This is true, but the same result may ensue through the destruction of some portion of hand-worked ordnance. It is impossible to have simplicity with any modern gun. It is legitimate, however, to argue that guns should not be mounted afloat which, in the event of anything happening to the hydraulic machinery, cannot be worked by hand.
The 38-ton gun thus loaded and controlled gave great satisfaction. Several of our turret ships are still armed with it, but in time a breech-loading gun will take its place. In 1873 the struggle between guns and armour produced what was then considered likely to prove the climax in each. To equip the ’Inflexible,' carrying 24 in. of armour, with equally powerful ordnance, guns of 80 tons weight were designed. They were originally intended to be of 14½-in. calibre, but were finally bored to 16 in. This gun was given a length of 18 calibres; the charge of powder was 450 lbs. and the projectile weighed 1700 lbs. At 1000 yards it could penetrate 23 in. of wrought-iron, and its initial velocity was 1600 ft. per second.The following table gives a general idea of the advance made in the size of guns from the time we discarded the 68-pounder smooth bore to the mounting of 80-ton muzzle-loading rifled ordnance in the
|Diameter of Bore||Weight of Gun.||Charge of Powder.||Weight of Projectile.||Velocity at Muzzle.||Penetration of Iron at 1000 Yards.|
|Ft. per Sec.
A few words must now be said about the ammunition. Experiments had shown that against armour cast-iron shot broke up like a snowball, while forged wrought-iron projectiles flattened, as if made of lead, against the hard or comparatively hard surface. In both cases the iron plates suffered little, because the energy was expended in breaking or distorting the missile. In this dilemma Captain Palliser came to the rescue with his ingenious device of hardening the front portion of a shot by chilling. The body is cast in an earthen mould, but the head is formed by a metal mould, which rapidly extracting the heat in this portion gives great hardness to the material. The result is that chilled shot of this nature are able to penetrate wrought-iron plates without breaking up or distortion. They are of cylindrical shape, with a pointed head, which against armour acts like a punch, forced into the plate by the energy of the other portion of the shot behind it. All are cast with a hollow core, which can be utilised for a bursting charge, but the space is so limited that such an addition is of little value. A great merit of these projectiles is their cheapness as compared with those now made of steel, so that they are still largely used for practice, and would be efficient against thinly armoured ships, though unable to cope with the thick steel or compound armour which has superseded wrought-iron for protection.
Other kinds of missiles are common shell and shrapnel shell. The former being required to contain a large bursting charge, have not sufficient strength to pass intact through armour, but are most destructive against any unarmoured portion of a ship. Shrapnel are iron cases containing a great number of small round shot, the case being fractured by a small burster at the required moment. The small shot then spread with the impetus previously acquired in flight. Against boats or bodies of men on shore they are very effective.
It has been mentioned that an improvement in the velocity obtained with the later muzzle-loading guns resulted from modifications in the powder employed. Not in the ingredients, because they had remained unaltered for centuries, and the same may be said of the proportions of the mixture, but by making each individual grain or pellet larger the whole charge took longer to consume. Hence, as the shot travelled down the bore continual increments of gas were generated imparting an augmenting velocity to the projectile, which should reach the muzzle when this was at maximum. If the gun was too short, a large portion of the powder would be blown out unconsumed, and result in wasted energy. Even with considerable addition to the length this occurs in a minor degree, as can be seen by an instantaneous photograph of a gun at the moment of discharge. As guns grew in size so did the grains of explosive composing the charge, first to what was termed pebble powder, and then to cubes of much larger dimensions. At a short distance from the gun unconsumed portions of these are a veritable hail of small projectiles.
In 1880 we appeared to have reached some finality in ordnance. We had advanced from 7 to 80 tons, and found no difficulty in manipulating on board ship the heaviest guns. There had been few accidents of a serious nature. The bursting of a 38-ton gun in the 'Thunderer' owing to the insertion of a double charge was a notable exception. The gun had actually missed fire the previous round without the crew being aware of it. It was then loaded again, and burst with great violence on being discharged. Being one of a pair in a turret, the discharge of the other gun had deceived the crew into a belief that both had gone off. Even spectators watching the target stated that they saw two shot strike the water. Such illusions are not uncommon. When two or more guns are fired at the same instant, and close together, especially if after recoil the gun automatically returns to its place, a single report may cause a doubt as to the discharge of both. This is the converse of the 'Thunderer's' case, but it may apply either way. One thing certainly was evident—such an accident could not occur with a breech-loading gun, because a second charge could not be inserted.But other causes were at work to bring about once more a complete revolution in our armaments. Foreign powers had in most cases adopted breech-loading guns, and by giving increased length were obtaining higher velocities. This meant increased penetration, in which respect we were being left behind. It became necessary for us to adopt the same principle, because we had arrived at the maximum of length in muzzle-loading ordnance for use in ships. We were undoubtedly slow to appreciate the necessity. There had been no loud demand from the navy for the change, and all ordnance coming to us from Woolwich, which is under the control of another department of the Government, there was naturally no great eagerness in that quarter for a move which would involve an entire change of pattern and construction. This matter belongs to the past, and I am willing to apportion blame to both sides. But when the great Elswick firm produced a 6-in breech-loader, throwing an 80-lb. projectile with a velocity of 1800 ft. per second, it was evident that we must at once discard all idea of adhering to our old guns. The Woolwich gun factory, under the able superintendence of Colonel Maitland, promptly grappled with the problem, and from that day we have gradually been overtaking the lost ground. There has been delay, of course, but to entirely rearm the British fleet with a weapon essentially different to all that had gone before in our experience was a stupendous task, and this should be recognised. Mistakes must necessarily occur, and one important change we did not at first make. We adhered to the principle of an inner steel barrel surrounded by wrought-iron coils. There was a distrust of steel, which it took some years to eradicate, though Krupp had always used this material entirely in the construction of his guns. A 6-in. gun on the wrought-iron coil system lately burst with great violence in the 'Cordelia' from some unknown cause.
Since guns of this pattern were made we have discarded the wrought-iron coils, and now strengthen the steel barrel with hoops of the same material. In again taking up breech-loading guns an important matter to decide was the method of closing the breech after insertion of the charge. We could follow the plan adopted by Krupp, of a wedge inserted at the side or a screw plug at the rear, as used in France. The latter was adopted, and with it the ingenious device for saving time of an interrupted screw. The plug is a solid steel block with a screw thread on outer surface. This is divided longitudinally into a certain number of equal parts, and then the screw threads entirely removed from alternate portions. In the screw thread of the gun similar portions are taken away, those remaining being opposite the blank spaces on the block. Consequently the latter can be pushed straight into the gun, and a portion of a turn engages the screw threads on each, so locking the breech without the loss of time involved by screwing the block in the ordinary way. As the cap or tube which ignites the charge is placed in this plug, which has a channel through the centre to allow the flame to pass into the chamber of the gun, there is a mechanical arrangement for preventing the tube being inserted until the breech piece—as this plug is termed—is thus locked. To prevent escape of gas to the rear it is necessary to effectually seal the end of the powder chamber. This is done by securing to the inner end of the breech piece either a thin steel cup, which on discharge of the gun is expanded against the inner sides of the chamber, or a pad of asbestos, which under pressure of the powder gas performs the same function. This, in technical language, is the obturator, and when we consider that the ignited gas exerts a pressure of some 15 tons to the square inch the importance of confining its energy to the base of the projectile may be understood.
As regards method of ignition, we have for some years utilised electricity for this purpose. On an unstable platform, such as a ship presents, it may be readily conceived that any delay in discharging a gun when it bears on an object must result in a miss. The remedy our ancestors had for this was to attain such close proximity to their object that a certain proportion of their projectiles could not fail to hit somewhere. But as close range is not always attainable, and may not be desirable, the delay in igniting the charge by means of a falling hammer or pulling a string should be eliminated. Electricity, being instantaneous, corrects this defect, the only motion required being to press a button. Its advantages are even more apparent when several guns are fired simultaneously and it is desired to lodge their projectiles in one spot. The apparatus simply consists of a galvanic battery, with wires leading to the guns and terminating in a fine filament of platinum silver wire, enclosed in a tube and surrounded by a small quantity of gunpowder. The current, when allowed to pass, heats the filament sufficiently to ignite the powder, and the flame passes on to the charge of the gun.Having once recognised the advantage of a breech-loader, we proceeded with the design and construction of different patterns suitable for large and small ships. They grew, in fact, similarly to the old muzzle-loaders. We mounted in succession 14, 22, 29, 45 and 67-ton guns, with a length of bore varying from 25 to 30 calibres. By augmenting the powder charges velocities were increased to 2100 ft. per second, the projectiles being over half a ton in weight. No difficulty was experienced by our officers and seamen in becoming proficient with such weapons, though it involved an entirely new procedure in their manipulation. Having been accustomed for years to insert powder first, one can imagine that to reverse the process does not come intuitively. Yet of many changes this is perhaps the simplest. The inevitable was cheerfully accepted. But when these new guns made a jump from 67 to 111 tons, and the number carried by a single ship fell from four to a pair, the policy of thus relying upon such a limited heavy armament, though reinforced by a number of smaller guns, began to be questioned. The case in favour of monster guns is that they represent concentrated power and the ability to do immense mischief if successfully applied. A single projectile from such a piece could disable the stoutest battle ship or penetrate the thickest armour carried. Nor, with the assistance of hydraulic apparatus, is their manipulation more complicated than with guns of half their weight. Though themselves offering a large mark, their very bulk is a protection against light projectiles. As against these points in their favour, three main objections may be stated. First, that the portion of a ship covered by the extremely thick armour is so small that hitting it under the varying conditions of a sea fight must be a chance. Second, it therefore becomes more profitable to attack the larger unarmoured area, or at any rate that area will be struck by the greater number of projectiles. For such work moderate sized guns are sufficient and superior to those throwing enormous bolts, which would pass through thin armour without impediment. Thirdly, there is the risk of half your principal armament being disabled by an accident or by a single lucky shot from your enemy. On the whole, therefore, I think the balance is in favour of smaller guns, and I view monster ordnance as one of the abnormal growths of peace which the rough test of war will sweep away. I have not dwelt on the element of time required for construction or cost. They should, however, be taken into consideration.
The projectiles used with our new guns are much the same in shape as before. For receiving rotation they have a copper band, which acts much in the same way as the lead coating in the first breech-loaders without the defect of stripping. Steel shot are, however, necessary to overcome the resistance of steel or compound armour, and to get satisfactory projectiles of this material has long been a difficult matter. France was before us in this respect, but our steel makers when called on rose to the occasion and now produce an efficient article.
Powder has gone through several phases. The ordinary black substance in cubes was replaced by prisms of brown material known as cocoa powder. Then came a demand for something which would give us energy without smoke, and all nations are seeking such an explosive. A propelling agent with this characteristic has been produced in this country by Professor Abel, known as cordite, from its resemblance when manufactured to a grey cord. It is more powerful than ordinary powder, without subjecting guns to an increased pressure, and is comparatively smokeless. One of the chief points to ascertain is whether, under the varying conditions of climate which our vessels experience in all parts of the world, this explosive will remain unaltered after a considerable lapse of time. We must have satisfactory tests in this respect before we can confidently admit it into our ships.No review of the progress of ordnance would be complete without notice of the great development of what are now called quick-firing guns. They have grown out of the mitrailleuse, first used in the Franco-German War, which consisted in a cluster of rifle barrels automatically fed with cartridges and fired by turning a handle, as sound is produced from a barrel-organ. At first discredited by defective mechanism, which caused stoppage of the action at critical moments, they have since been greatly improved in the systems of Gatling, Gardner, Nordenfelt, and Maxim. The last named has brought to considerable perfection a gun in which the energy of recoil is utilised to perform all the operations of extracting the fired cartridge, reloading, and firing without human interference. Set to operate in this way the gun will continue to fire until its ammunition is exhausted. Against bodies of men the machine rifle—as it might be more fitly termed—can work great execution, but to stop torpedo boats requires a heavier projectile, so that Mr Hotchkiss and Mr Nordenfelt designed a machine gun of larger calibre. In that of the former the barrels revolve, while in Mr Nordenfelt's gun they are stationary. Both are effective weapons. Then came a demand for a single-barrel gun which could throw shot of about 6 lbs. weight and fire several rounds a a minute. The ammunition was to be made up like a rifle cartridge instead of, as formerly with small guns, having powder and projectile separate. Messrs Hotchkiss and Nordenfelt both complied with the demand, and these were termed quick-firing guns. They are now largely represented in all our ships. An important feature was aiming and firing from the shoulder by means of a wooden shoulder piece attached to the gun, which being accurately balanced could thus be freely moved, horizontally and vertically, with little exertion of the body. The movement of an object could thus be followed almost as easily as the flight of a bird with a fowling piece. These guns have considerable range and penetration; and would be effective against the unarmoured parts of a ship, while the 3-pounder, a smaller piece on the same principle, is specially adapted to meet a torpedo attack.
Observing the success of small quick-firing guns, Sir William Armstrong's firm were not long in extending it to larger ordnance. An increase in the rapidity of fire of all guns is an advantage which every sea fight has endorsed, so a gun having a calibre of 4.7 in. and throwing a projectile of 45 lbs. was designed. The projectile is separate from the powder cartridge, as being more convenient to handle. Very satisfactory results have been obtained with this gun, from which about ten aimed shots a minute can be fired.
The principle, however, has not attained finality, because a 6-in. quick-firing gun has since been constructed, and proved successful. In this gun, also, the projectile is separate from the powder, as it weighs 100 lbs., and is inserted previous to the cartridge containing he explosive and cap. The case of this is made of brass, and though the construction of this portion is expensive the cartridge cases can be used over again when fired. The rapidity of aimed fire from this gun is about eight rounds a minute. Cordite has been tried with this gun, and it is found that 17 lbs. of this explosive will give the same energy to the projectile as 50 lbs. of ordinary powder, without increased pressure in the chamber.
It is difficult to say what will be the further development of quick-firing guns. One thing seems to me probable, that all charges will be contained in copper cylinders, instead of being enveloped in silk cloth, by which moisture will be excluded, and the explosive guarded against rough usage. Greater rapidity of fire with heavy ordnance then becomes more dependent upon improved training and practice than small details of mechanism in the guns.
- This is the principal cause of obtaining greater rapidity of fire.
- Mr Elmore's ingenious process of copper deposition and hardening seems likely to answer this requirement.