Heavy Ordnance.
As with rifles and the smaller forms of artillery, so also with heavy ordnance, the changes and improvements within the last fifty years have been greater than those made during the course of all the previous centuries.
These changes have affected alike not only the materials from which a weapon is manufactured, the relative size of calibre and length of bore, the fashion of mounting and firing, but also the form and weight of the projectile, the velocity with which it is thrown, and even the substances used in expelling it from the gun.
Compare for a moment the old cast-iron muzzle-loaders, stubby of stature, which Wellington’s bronzed veterans served with round cannon balls, well packed in greasy clouts to make them fit tight, or with shell and grape shot, throughout the hard-fought day of Waterloo, from a distance which the chroniclers measure by paces, so near stood the opposing ranks to one another.
Or stand in imagination upon one of Nelson’s stately men-o’-war and watch the grimy guns’ crews, eight or ten to each, straining on the ropes. See the still smoking piece hauled inboard, its bore swabbed out to clean and cool it, then recharged by the muzzle; home go powder, wad, and the castor full of balls or the chain shot to splinter the enemy’s masts, rammed well down ere the gun is again run out through the port-hole. Now the gunner snatches the flaming lintstock and, signal given, applies it to the powder grains sprinkled in the touch-hole. A salvo of fifty starboard guns goes off in one terrific broadside, crashing across the Frenchman’s decks at such close quarters that in two or three places they are set on fire by the burning wads. Next comes a cry of “Boarders!” and the ships are grappled as the boarding-party scrambles over the bulwarks to the enemy’s deck, a brisk musket-fire from the crowded rigging protecting their advance; meanwhile the larboard guns, with their simultaneous discharge, are greeting a new adversary.
Such was war a century ago. Compare with it the late South African Campaign where the range of guns was estimated in miles, and after a combat lasting from morn to eve, the British general could report: “I do not think we have seen a gun or a Boer all day.”
The days of hand-to-hand fighting have passed, the mêlée in the ranks may be seen no more; in a few years the bayonet may be relegated to the limbo of the coat-of-mail or the cast-iron culverin. Yet the modern battle-scene bristles with the most death-dealing weapons which the ingenuity of man has ever constructed. The hand-drawn machine-gun discharges in a couple of minutes as many missiles as a regiment of Wellington’s infantry, with a speed and precision undreamt of by him. The quick-firing long-range naval guns now in vogue could annihilate a fleet or destroy a port without approaching close enough to catch a glimpse of the personnel of their opponents. The deadly torpedo guards our waterways more effectually than a squadron of ships.
All resources of civilisation have been drawn upon, every triumph of engineering secured, to forge such weapons as shall strike the hardest and destroy the most pitilessly. But strange and unexpected the result! Where we counted our battle-slain by thousands we now mourn over the death of hundreds; where whole regiments were mown down our ambulances gather wounded in scattered units. Here is the bright side of modern war.
The muzzle-loading gun has had its day, a very long day and a successful one. Again and again it has reasserted itself and ousted its rivals, but at last all difficulties of construction have been surmounted and the breech-loader has “come to stay.”
However, our services still contain a large number of muzzle-loading guns, many of them built at quite a recent period, and adapted as far as possible to modern requirements. So to these we will first turn our attention.
The earliest guns were made of cast-iron, but this being prone to burst with a large charge, bronze, brass, and other tougher materials were for a long time employed. Most elaborately chased and ornamented specimens of these old weapons are to be seen in the Tower, and many other collections.
In the utilitarian days of the past century cheapness and speed in manufacture were more sought after than show. Iron was worked in many new ways to resist the pressure of explosion.
Armstrong of Elswick conceived the idea of building up a barrel of coiled iron by joining a series of short welded cylinders together, and closing them by a solid forged breech-piece. Over all, again, wrought-iron coils were shrunk. Subsequently he tried a solid forged-iron barrel bored out to form a tube. Neither make proving very satisfactory, steel tubes were next used, but were too expensive and uncertain at that stage of manufacture. Again coiled iron was called into requisition, and Mr. Frazer of the Royal Gun Factory introduced a system of double and triple coils which was found very successful, especially when a thin steel inner tube was substituted for the iron one (1869).
All these weapons were rifled, so that there was of necessity a corresponding difference in the projectile employed. Conical shells being used, studs were now placed on the body of the shell to fit into the rifling grooves, which were made few in number and deeply cut. This was apt to weaken the bore of the gun; but on the other hand many studs to fit into several shallow grooves weakened the cover of the shells.
Various modifications were tried, and finally a gas-check which expands into the grooves was placed at the base of the shell.
The muzzle-loader having thus been turned into a very efficient modern weapon the next problem to be solved was how to throw a projectile with sufficient force to penetrate the iron and steel armour-plates then being generally applied to war-ships. “Build larger guns” was the conclusion arrived at, and presently the arsenals of the Powers were turning out mammoth weapons up to 100 tons, and even 110 tons in weight with a calibre of 16 inches and more for their huge shells. Then was the mighty 35-ton “Woolwich Infant” born (1872), and its younger but still bigger brothers, 81 tons, 16-inch bore, followed by the Elswick 100-ton giants, some of which were mounted on our defences in the Mediterranean. But the fearful concussion of such enormous guns when fixed in action on board ship injured the superstruction, and even destroyed the boats, and the great improvements made in steel both for guns and armour soon led to a fresh revolution. Henceforward instead of mounting a few very heavy guns we have preferred to trust to the weight of metal projected by an increased number of smaller size, but much higher velocity. And these guns are the quick-firing breech-loaders.
The heaviest of our up-to-date ordnance is of moderate calibre, the largest breech-loaders being 12-inch, 10-inch, and 9.2-inch guns. But the elaborateness of its manufacture is such that one big gun takes nearly as long to “build up” as the ship for which it is destined. Each weapon has to pass through about sixteen different processes:—
(1) The solid (or hollow) ingot is forged.
(2) Annealed, to get rid of strains.
(3) It is placed horizontally on a lathe and rough-turned.
(4) Rough-bored in a lathe.
(5) Hardened. Heated to a high temperature and plunged, while hot, into a bath of rape oil kept cold by a water-bath. It cools slowly for seven to eight hours, being moved about at intervals by a crane. This makes the steel more elastic and tenacious.
(6) Annealed, i.e. reheated to 900° Fahr. and slowly cooled. Siemens’ pyrometer is used in these operations.
(7) Tested by pieces cut off.
(8) Turned and bored for the second time.
(9) Carefully turned again for shrinkage. Outer coil expanded till large enough to fit easily over inner. Inside, set up vertically in a pit, has outside lowered on to it, water and gas being applied to make all shrink evenly. Other projections, hoops, rings, &c., also shrunk on.
(10) Finish—bored and chambered.
(11) Broached, or very fine bored, perhaps lapped with lead and emery.
(12) Rifled horizontally in a machine.
(13) Prepared for breech fittings.
(14) Taken to the Proof Butts for trial.
(15) Drilled for sockets, sights, &c. Lined and engraved. Breech fittings, locks, electric firing gear, &c., added. Small adjustments made by filing.
(16) Browned or painted.
When worn the bore can be lined with a new steel tube.
These lengthy operations completed, our gun has still to be mounted upon its field-carriage, naval cone, or disappearing mounting, any of which are complicated and delicately-adjusted pieces of mechanism, the product of much time and labour, which we have no space here to describe.
Some account of the principal parts of these guns has already been given, but the method by which the breech is closed remains to be dealt with.
It will be noticed that though guns now barely reach half the weight of the monster muzzle-loaders, they are even more effective. Thus the 46-ton (12-inch) gun hurls an 850-lb. projectile with a velocity of 2750 foot-seconds, and uses a comparatively small charge. The famous “81-ton” needed a very big charge for its 1700-lb. shell, and had little more than half the velocity and no such power of penetration. This change has been brought about by using a slower-burning explosive very powerful in its effects; enlarging the chamber to give it sufficient air space, and lengthening the chase of the gun so that every particle of the powder-gas may be brought into action before the shot leaves the muzzle. This system and the substitution of steel for the many layers of welded iron, makes our modern guns long and slim in comparison with the older ones.
To resist the pressure of the explosion against the breech end, a tightly-fitting breech-plug must be employed. The most modern and ingenious is the Welin plug, invented by a Swedish engineer. The ordinary interrupted screw breech-plug has three parts of its circumference plane and the other three parts “threaded,” or grooved, to screw into corresponding grooves in the breech; thus only half of the circumference is engaged by the screw. Mr. Welin has cut steps on the plug, three of which would be threaded to one plane segment, each locking with its counterpart in the breech. In this case there are three segments engaged to each one left plane, and the strength of the screw is almost irresistible. The plug, which is hinged at the side, has therefore been shortened by one-third, and is light enough to swing clear with one touch of the handwheel that first rotates and unlocks it.
The method of firing is this: The projectile lifted (by hydraulic power on a ship) into the loading tray is swung to the mouth of the breech and pushed into the bore. A driving-band attached near its base is so notched at the edges that it jams the shell closely and prevents it slipping back if loaded at a high angle of elevation. The powder charge being placed in the chamber the breech-plug is now swung-to and turned till it locks close. The vent-axial or inner part of this breech-plug (next to the charge), which is called from its shape the “mushroom-head,” encloses between its head and the screw-plug the de Bange obturator, a flat canvas pad of many layers soaked with mutton fat tightly packed between discs of tin. When the charge explodes, the mushroom-head—forced back upon the pad—compresses it till its edges bulge against the tube and prevent any escape of gas breechwards.
The electric spark which fires the charge is passed in from outside by means of a minute and ingenious apparatus fitted into a little vent or tube in the mushroom-head. As the electric circuit cannot be completed till the breech-plug is screwed quite home there is now no more fear of a premature explosion than of double loading. If the electric gear is disordered the gun can be fired equally well and safely by a percussion tube.
This description is of a typical large gun, and may be applied to all calibres and also to the larger quick-firers. The mechanism as the breech is swung open again withdraws the empty cartridge. So valuable has de Bange’s obturator proved, however, that guns up to the 6-inch calibre now have the powder charge thrown into the chamber in bags, thus saving the weight of the metal tubes hitherto necessary.
Of course several types of breech-loading guns are used in the Service, but the above are the most modern.
The favourite mode of construction at the present time is the wire-wound barrel, the building up of which is completed by covering the many layers of wire with an outer tube or jacket expanded by heat before it is slipped on in order that it may fit closely when cold. A previous make, without wire, is strengthened by rings or hoops also shrunk on hot.
The quick-firers proper are of many sizes, 8-inch, 7.5-inch, 6-inch, 4.7-inch, 4-inch, and 3-inch (12-pounders). The naval type is as a rule longer and lighter than those made for the rough usage of field campaigning and have a much greater range. There are also smaller quick-firers, 3-pounders and 6-pounders with bore something over 1-inch and 2-inch (Nordenfelt, Hotchkiss, Vickers-Maxim). Some of the high velocity 12-pounders being employed as garrison guns along with 6-inch and 4.7-inch, and the large calibre howitzers.
We still use howitzer batteries of 5-inch bore in the field and in the siege-train, all being short, rifled, breech-loading weapons, as they throw a heavy shell with smallish charges at a high angle of elevation, but cover a relatively short distance. A new pattern of 8-inch calibre is now under consideration.
It is interesting to contrast the potencies of some of these guns, all of which use cordite charges.
| Calibre. | Charge. | Weight of Shot. | Muzzle Velocity in Foot Seconds. | Number of Rounds per Minute. |
| 12 inch | 207 lbs. | 850 lbs. | 2750 | 1 |
| 8 inch | 52 lbs | 210 lbs | 2750 | 5 |
| 6 inch | 25 lbs | 100 lbs | 2775 | 8 |
| 4.7 inch | 9 lbs | 45 lbs | 2600 | 12 |
| 3 inch | 2 lbs. 9 oz. | 12.5 lbs | 2600 | 20 |
In the armament of our fine Navy guns are roughly distributed as follows:—81-ton, 13-1/2-inch, and superseded patterns of machine-guns such as Gatling’s, Gardner’s, and Nordenfelt’s, besides a few surviving muzzle-loaders, &c., are carried only by the oldest battleships.
The Simms armour-clad motor-car for coast defence.
Maxim guns and Pom-pom in action.
The first-class battleships are chiefly supplied with four 12-inch guns in barbettes, twelve 6-inch as secondary batteries, and a number of smaller quick-firers on the upper decks and in the fighting tops, also for use in the boats, to which are added several Maxims.
The first-class cruisers have 9.2 as their largest calibre, with a lessened proportion of 6-inch, &c. Some of the newest bear only 7-1/2 or 6-inch guns as their heaviest ordnance; like the second-class cruisers which, however, add several 4.7’s between these and their small quick-firers.
Vessels of inferior size usually carry nothing more powerful than the 4.7.
All are now armed with torpedo tubes.
These same useful little quick-firers and machine-guns have been the lethal weapons which made the armoured trains so formidable. Indeed, there seems no limit to their value both for offence and defence, for the battle chariot of the ancient Briton has its modern successor in the Simms’ motor war car lately exhibited at the Crystal Palace. This armour-plated movable fort is intended primarily for coast defence, but can work off beaten tracks over almost any sort of country. It is propelled at the rate of nine miles an hour by a 16-horse-power motor, carrying all its own fuel, two pom-poms, two small Maxims, and 10,000 rounds of ammunition, besides the necessary complement of men and searchlights for night use, &c., &c.
The searchlight, by the way, has taken the place of all former inventions thrown from guns, such as ground-light balls, or parachute lights with a time-fuse which burst in the air and remained suspended, betraying the enemy’s proceedings.
In like manner the linked chain and “double-headed” shot, the “canister”—iron balls packed in thin iron or tin cylinders which would travel about 350 yards—the “carcasses” filled with inflammable composition for firing ships and villages, are as much out of date as the solid round shot or cannon-ball. Young Shrapnell’s invention a century ago of the form of shell that bears his name, a number of balls arranged in a case containing also a small bursting-charge fired either by percussion or by a time-fuse, has practically replaced them all. Thrown with great precision of aim its effective range is now up to 5000 yards. A 15-pounder shrapnell shell, for instance, contains 192 bullets, and covers several hundred yards with the scattered missiles flying with extreme velocity.
Common shell, from 2-1/2 to 3 calibres long, contains an explosive only. Another variety is segment shell, made of pieces built up in a ring with a bursting charge in the centre which presently shatters it.
The Palliser shell has a marvellous penetrating power when used against iron plates. But, mirabile dictu! experiments tried within the past few months prove that a soft cap added externally enables a projectile to pierce with ease armour which had previously defied every attack.