The barrels of the machine guns we have described do not, as is generally supposed, radiate; on the contrary, they are arranged in a perfectly parallel direction. In consequence of this, the bullets are at short ranges directed nearly to one spot. The Gatling gun was adopted as a service weapon by the British navy, and in several minor actions it had proved effective, but in its original form it was superseded by the Gardner gun, in which the barrels are fixed horizontally side by side, and are in number five or fewer; each barrel is able to fire 120 rounds per minute. A new system of feed was afterwards applied to the Gatling gun by Mr. Accles, by means of which this gun was greatly improved and its rate of firing was increased to more than 1,000 rounds per minute; indeed, 80 rounds have been fired from it within 2 seconds. The Gatlings in this improved form have ten barrels, and are provided with feed drums, each containing 104 cartridges, and capable, when empty, of being almost instantly replaced by a full one. The contents of one drum can, if necessary, be discharged in about 2¼ seconds, so that in this time 104 rifle bullets would be fired; or considerably more than the rate of 1,000 rounds per minute could easily be maintained. The weapon is so mounted, that without moving its carriage it can be pointed at any angle of elevation or depression, and through a considerable lateral range.
Mr. Nordenfelt has brought out a machine gun, which, on account of the simplicity and strength of its firing mechanism, has proved the most reliable weapon of its class, and it also has been adopted into the British service, and indeed into that of nearly every nation in the world. In this gun there are five barrels arranged as in the Gardner, but the firing is operated by a lever working backwards and forwards at the rate of 600 rounds per minute.
Fig. 105e.—A Hotchkiss Gun.
In the firing of all these weapons, by turning a crank, or moving a lever at one side, any attempt at exact aiming must obviously be difficult if not impossible, from the liability of the gun to get moved. Several designs have been proposed for making the firing mechanism entirely automatic so as to require no effort on the part of the firer, whose attention can then be directed solely to pointing the piece. It would not be easy to explain in detail the way in which this is accomplished in these very ingenious guns; for while the principle of their action is sufficiently clear, namely, that the force of the recoil is made to extract the spent cartridge, open the breech, insert a fresh cartridge, close the breech, and fire the charge, the mechanism of the reacting springs, etc., by which this is effected could scarcely, even by the aid of elaborate diagrams, be made intelligible to any other than a gunsmith. The Maxim is one of those automatic guns: it has but one barrel, and after the first discharge it will go on firing with marvellous rapidity the cartridges supplied to it in a continuous chain, and this without any deviation from such direction as may be given to it by the operator, for he has neither crank to turn nor lever to move, but merely sits behind an iron shield directing the weapon at will, which, without interference, fires hundreds of shots per minute from one barrel, so long as the long bands of cartridges are supplied to it.
Mr. Nordenfelt and Mr. Hotchkiss have also both contrived quick firing guns for 1–lb., 3–lb., and 6–lb. projectiles, and these, it has been thought, will be of great service in naval warfare as against torpedo boats.
Though the automatic mechanism, whereby the breech operations are all performed by the force of the recoil of the barrel, which is allowed to slide backwards, and is then returned to its place by a spring, is too complicated for illustration here, mention may be made of a quite recent device by which the recoil action is dispensed with, and the mechanism so far simplified that scarcely more than half the number of parts in the lock mechanism are required. Imagine a closed tube beneath the barrel, parallel to it, and communicating with it only by a small boring near the muzzle; through this opening the expanding gases will pass, in a degree depending on its size and position, and by their action on a piston near the breech, impulses are supplied that will actuate the lock mechanism so long as cartridges are supplied, as they may be in a continuous band. A weapon of this construction has been already tried, and its discharges are so rapid that the sound of them is described as being quite deafening. This plan appears to be equally applicable to small arms, and to machine or field guns. A very effective gun of the kind, which fires ordinary rifle bullets, has been contrived by Mr. Hotchkiss, and is represented in Fig. [105e]. It is capable of sending forth as many as 1,000 shots in one minute.
Modern ordnance has required certain modifications in the making of gunpowder, so that the original name of powder would now hardly be applicable at all. The large charges now used, if introduced in the form of fine powder, would certainly shatter the guns from the suddenness of the exploding force. Hence the material is made up into larger or smaller masses, generally rounded like small pebbles. The explosive used for the huge 110–ton guns presents itself in the form of chocolate-coloured hexagonal prisms, two or three inches long and about an inch in diameter. These are obtained by compressing the specially prepared material into moulds with a hydraulic press. The reason for this process is that, in order to obtain precision and uniformity in the effects, not only must the composition of the powder be always the same, but the size, shape, weight, and number of the several portions that make up the charge must be invariable. It has not been found possible to fire one of these monster guns many times without such signs of deterioration as would suggest a short “life” for each of them. But the greatest necessity for modern fire-arms is a smokeless powder or other explosive. It is obvious that the advantages of quick firing, whether of large or of small fire-arms, are greatly reduced if the soldier or gunner is prevented by smoke from taking aim. The invention of a smokeless gunpowder has several times been announced, and great advances have, indeed, been made towards its realization. Certain compositions, which appeared to meet the requirement of being practically smokeless, have, however, been found liable to chemical changes, or to corrode the bore, or to possess other objectionable properties. In this country the explosive coming into use as best adapted for quick firing guns, etc., presents itself in appearance like whitish or grey strings, and has hence received the name of cordite. The composition and mode of manufacture of these new substitutes for gunpowder are not readily disclosed, each military authority jealously guarding its own secrets. The problem of smokeless powder has, however, been almost completely solved, for at a military review that took place on the Continent in 1889, the discharge of the rifles (loaded with blank cartridges, of course) is said to have been attended with no more smoke than the puff of a cigar. The new invention will cause some changes in military tactics, for the manœuvres formerly executed under cover of the battle smoke will no longer be possible. Some particulars as to the nature of smokeless powders will be found in the article on “Explosives.”
