Navies of the world

All muzzle-loading projectiles are provided with studs for rotation. They are of gun-metal, swedged into countersunk holes, in two rows. The loading side of all grooves is cut back so as to double the width of the groove at the muzzle, in order to facilitate the insertion of the projectile.

Papier-maché wads are used in front of the heavier projectiles to keep them from slipping forward out of place. These wads are very slightly less than the calibre of the gun, and about an inch in thickness. A hole is bored through the centre, large enough to leave a clear space for the fuse. A short papier-maché tube projects from the forward side of the wad, which serves to attach it to the rammer when loading, and hold it vertical while the charge is going home.

Shell-charges for Palliser projectiles are introduced in serge bags to prevent premature explosions.

FUSES.

Both time and percussion fuses are used in the navy. The time-fuses are the Boxer and the Armstrong; the latter used only with breech-loading segment shell. The percussion fuse is the Pettman.

The Boxer time-fuse has a beech-wood body and is conical in shape. The fuse composition is a vertical column in a centre channel which is not bored entirely through the bottom, a base being left to receive the set-back of the column on firing. Two side channels are bored from the bottom nearly to the top, and are filled with mealed powder. Holes are bored from the outside into these channels one tenth of an inch apart, and the composition burns at the rate of one inch in five seconds, so that each hole represents a half-second. The head of the fuse is closed by a safety-cap, which is removed before loading. The time of burning is set by boring through the desired hole into the composition. The bottom hole is always bored through.

The Armstrong time-fuse is made of gun-metal. A ring of fuse composition similar to that of the old Bormann fuse is pressed in a channel whose outer wall is marked in inches and tenths. This fuse composition is covered by a movable collar which is kept in place by a nut. Attached to this movable collar is a small chamber containing a detonator. When the gun is fired, this detonator ignites the composition at the point at which it is set, and the flame travels around until it meets the magazine, or blowing-chamber, which communicates the flame to the shell-charge.

The Pettman percussion fuse is made up of seven principal parts—the body, top plug, steady plug, detonating ball, cone plug, lead cap, and bottom plug. The top and bottom plugs are set fast; the shock of firing sets back all the other parts, crushing the lead cap over the cone and bottom plugs, which by their shape are all held fast when jammed together. The detonating ball, whose surface is covered with a detonating composition, is carried straight back and prevented from coming in contact with the sides of the chamber by the steady plug. When the projectile strikes, however, the steady plug starts forward and releases the ball, which, coming in contact with the sides of the fuse, explodes the detonating powder and the flame is carried by holes through the lower plugs to the charge.

PRIMERS.

Gun-locks are no longer used in the navy. Guns are fired by means of either the friction or the electric tube. The quill friction-tube is used exclusively for the navy. This tube is of two sizes, the short and the long, the latter being used with the heavy calibres. The quill is driven with mealed powder, and a hole is pierced through the centre. The top and bottom are stopped with shellac putty. In the upper part of the tube an iron-wire friction-bar is inserted, having a sprinkling of detonating composition and mealed powder on one side. The top of the tube is strengthened by a thread woolding and a leather loop, which slip over a pin placed forward of the vent.

The naval electric tube consists of a quill body and a xylonite bottom, the quill being of a diameter to slip completely into the vent. Within this quill are insulated terminals of wire connected by a platinum-silver wire bridge surrounded by priming composition. The whole tube goes into the vent, a stop on the insulating wires preventing it from going too far.

SIGHTS.

All muzzle-loading guns, except turret-guns and boat-guns, have six sights—three hind-sights (two tangent and one centre) and three trunnion-sights. Boat-guns have one centre hind and one fore sight, and turret-guns have turret-sights. All guns except boat-guns have wood scales, and all guns in covered batteries, except turret-guns, have graduated arcs on the pivot-circles.

The tangent-sight is a rectangular steel bar rounded off on two sides, and having a gun-metal head in which slides a gun-metal leaf. The gun-metal leaf slides in a socket, and is provided with a simple clamp-screw. These sights are graduated on the four sides. In general, the forward side is graduated to 10´ from 0 up to 12°. The right side is marked from 100 up to 4000 yards, and for seconds of fuse from 1 to 30—both graduations for common shell with the full charge; the rear side from 100 to 4800 yards for Palliser shot or shell with the battering-charge; the left side from 100 to 4800 yards, and from 1 second to 34 seconds, for common shell with battering-charge.

The centre hind-sight is a hexagonal gun-metal bar with the sliding leaf marked like the tangent-sights, but shorter.

All hind-sights are set at a permanent angle of deflection.

The fore or trunnion sights consist of a pillar and collar of gun-metal, a small steel leaf, and a screw for fixing the leaf. A gun-metal socket is fixed in the gun, and the sight secured in this socket by a double bayonet-joint, so that it may be readily removed or replaced without requiring a special adjustment.

With turret-guns the sights are placed on top of the turret. Each turret is provided with a number of man-holes large enough to admit the head and shoulders. For each man-hole a pair of sights is adjusted, the line of sight being parallel to the axis of the gun. In some turrets, in order to prevent exposure, mirrors are arranged so that these sights may be used by persons in the turret.

The wood scale is a wooden bar used in connection with marks on the rear face of the cascabel. This face is marked from 0 to 3½° for both elevation and depression. The wood scale is a square bar having its four sides marked to yards for different charges. When the gun is placed in position aboard ship, this scale is cut so that its zero and the cascabel zero shall coincide with the guns at level, on an even keel.

The sights for breech-loaders are similar to those of muzzle-loaders, except that what is known as the barrel-headed sliding leaf is used, and there are no centre-sights.

DISTINGUISHING MARKS OF PROJECTILES.

The common shell is known from its carrying a fuse in the point which is cut off for that purpose.

The double shell is known by its disproportion of length to diameter.

The Palliser projectile is known from its sharp point.

The shrapnel is known from the joint which connects the head to the body.

Fragments of a copper disc would denote that Palliser projectiles were used, and a fragment of the head of a Palliser projectile is easily recognizable by the grain of the iron.

PALLISER CONSTRUCTION.

The Palliser construction is entirely applied to the conversion of old cast-iron smooth-bore guns into efficient rifles. In this system the bore of the gun is reamed out to a sufficient diameter to permit the insertion of a coiled wrought-iron tube. This tube is made up of a number of short coiled sections end-welded together. The rear of the tube is planed down, and a jacket (coiled with the spirals opposite in direction to the tube) is shrunk on. The breech end of the tube is closed by a wrought-iron disc screwed into place. The surface of the tube is then turned to a snug but not tight fit in the casing or gun, and is inserted, being held in place by a muzzle screw-collar. A screw is tapped through the chase into the tube to keep it from turning. The old vent is bored through and the gun is submitted to a course of proof-firing with full charges, to expand the tube against the wall of the casing, making a snug fit. A spiral slot is cut around the tube from front to rear, and carried through the cascabel as a tell-tale for the escape of gas in case the tube is split or cracked through at a weld. These guns are extraordinarily long-lived, and have been extensively used by the governments of Great Britain and the United States.

Palliser Projectiles. See Pages 208-210.

WHITWORTH CONSTRUCTION.

Whitworth ordnance is used almost exclusively in the Brazilian Navy, and is the regulation type. The Whitworth construction belongs to the all-steel type, and differs in almost every particular from the other types. The guns are both muzzle and breech-loaders. The body of the gun consists of a steel tube reinforced by steel hoops. The tube is cast solid and submitted to a heavy hydraulic pressure while in a molten state, giving the metal as it solidifies a perfectly homogeneous crystallization throughout. This tube is bored completely through, and in the muzzle-loaders the breech end is closed by a steel screw-plug. The hoops are hollow cast and forged on a mandrel, the lengths in the different layers being accurately turned and screwed together; the layers are then put on the gun cold and forced home (from the muzzle end) by hydraulic pressure, the forcing being carefully gauged so as not to crush the metal of the tube.

The breech-loaders are slotted across the rear face in such a manner that the rear face of the block is entirely exposed, thus saving in length of breech of gun. The breech-block is cubical, and is traversed along the upper and lower surfaces by heavy threads set at an angle with the face of the block. These threads travel in heavy male threads in the slot, the system forming the support for the thrust on the block. Attached to the rear face of the block is a weighted crank which revolves a cogged wheel housed in the block and travelling in a rack in the rear of the lower side of the block-seat. In guns of heavy calibre the system is reversed, the crank and wheel housing in the rear of the gun and the rack in the block. By means of this gearing the block is moved transversely, masking and unmasking the bore, the left end of the block being cut for a loading-hole. A stop on the face of the breech locks the block when home and catches it at the proper point when open.

The Whitworth groove is of a peculiar nature, being almost a perfect hexagon, and having an extremely sharp twist of from one turn in 2 feet in the 2-pdr. to one turn in 13 feet in the 9-inch.

The projectiles are cut to fit the grooves, the armor-punching ones being of compressed steel.

THE VAVASSEUR CONSTRUCTION.

Vavasseur ordnance is used considerably in China, and has found some use in other quarters of the world. The gun belongs to the steel type. It consists of a mild-steel oil-tempered tube, reinforced by steel hoops, the hoops being narrow and numerous and shrunk on. The trunnion-hoop is of wrought iron. The gun has, properly speaking, ribs instead of grooves, the grooves being cut in the projectiles. The twist is a constant one.

The gun-carriage possesses a peculiar recoil arrangement, consisting of a heavy screw-shaft traversing the middle of the slide and carrying at its forward end a wrought-iron friction-wheel with a metal strap worked by a lever, by which any desired amount of friction may be applied. Attached to the carriage is a sleeve or clutch grasping the screw-shaft. When the gun recoils, the motion of the sleeve along the shaft causes the latter to revolve, the friction being regulated by the friction-band. For running in and out a large cog-wheel is fixed to the inside of each carriage-bracket, the cogs taking in racks along the sides of the slide. In starting the gun out, the motion of starting slacks the friction-band on the screw-shaft, allowing the gun to run freely; for controlling the motion in a seaway, a small friction-brake on the rear of the slide is used. The carriage is mounted on eccentric rollers, and the movement of throwing them out of or into action ungears or gears the running-out cranks outside of the brackets, so that in recoiling the cranks are not thrown around. The chamber of the Vavasseur gun, as originally constructed, is smaller than the bore, being in this a reversal of the present accepted true principle, and limiting the guns to small charges and low velocities.

French Ordnance.

• A = Over all.
• B = Bore.
• C = Number of Grooves.

• D = Twist of Rifling.
• E = Gun, including Breech-block.
• F = Breech-block.
• G = Preponderance.

• A = Carriage.
• B = Slide.
• C = Steel.
• D = Chilled.
• E = Common.
• F = Canister.
• G = Bursting Charge Common Shell.

• A = Steel and Chilled Shot.
• B = Common Shell.
• C = Ordinary.
• D = Saluting.
• E = Steel.
• F = Chilled.
• G = Common.

GUNS.

Smooth-bore guns are entirely obsolete, except for saluting purposes at dock-yards.

The rifled ordnance consists of the cast-iron breech-loader, model 1870, the cast-iron breech-loader, model 1864-67, the cast-iron muzzle-loader, model 1858-60, the bronze muzzle-loader, the mitrailleuse, and the Hotchkiss machine-gun. A new all-steel pattern is being introduced into the service, whose attachments are quite similar to the model of 1870.

The two models of breech-loaders differ radically in the style of rifling, and although the breech mechanism is the same in principle in both types, it is quite different in detail.

Breech-Loader, Model 1870.

Guns of this type consist of a cast-iron body strengthened by a steel tube and steel hoops. The steel tube, which is about one quarter of a calibre in thickness, is inserted into the bore from the rear, and is set fast by a heavy male screw-thread worked at its rear end. It extends a short distance forward of the trunnions. The steel hoops are shrunk on over the cast-iron body, and cover all that part occupied by the tube. For the 14-cm. calibre there is but one row of hoops; for the higher calibres two rows breaking joints. The trunnions form a part of the hoop next to the forward one. In all calibres above 16-cm. this trunnion-hoop is thicker than the others, and forms a salient on the surface of the gun.

The bore is rifled on the multigroove system, with an increasing twist of from 0° at the breech to 4° at the muzzle, the direction of the twist being from right to left (contrary to the invariable rule in other countries). The chamber proper is divided into four parts: the shot-chamber, the powder-chamber, the gas-check seat, and the breech-block seat.

The shot-chamber is conical in shape, small end forward, the rifling vanishing at this point in an easy slope. The diameter of this end is the same as that of the bore measured across the grooves. The rear end is joined to the powder-chamber by a second small cone, against which the rear ring of the projectile takes when home.

The powder-chamber is cylindrical, and of a diameter slightly greater than that of the bore.

The gas-check seat is of considerably greater diameter than the powder-chamber. It is conical in shape, small end forward.

The breech-block seat is cylindrical, having a heavy screw-thread around its wall, which is cut into three equal sectors, leaving three blanks of the same width. One of these blanks comes at the bottom of the seat, in order to allow the breech-block to slide back and forth.

The breech mechanism consists of two main parts, the block and the console or bracket, which is hinged to the face of the breech and holds the block when it is withdrawn from its seat.

The breech-block is a steel cylinder having heavy screw-sectors about its surface to correspond with those in the seat. The last turn of screw-thread is left entire in order to relieve the shock of closing the breech. The forward face is made movable in order that when it becomes worn and scored by the action of the powder-gas it may be changed. This face is a steel disc which sets flat against the face of the block, and is of the same diameter. It seats in the face of the block by means of a smaller cylinder or trunnion, and projecting from the rear of this trunnion is a steel rod, which passes completely through the axis of the block and carries the vent. In order to prevent the disc from having any independent motion, a small tenon on its rear face enters a socket in the face of the block. The disc is keyed fast by a small pin which is screwed radially through the block near the middle, the end of the pin taking in a score cut in the vent-rod. A small catch, projecting from the rear lower side of the block, holds the console in place when the breech is closed. The rear face of the block is provided with two parallel handles screwed to it, to assist in moving it, and a long crank-handle between them for revolving the block. At the end of this crank-handle there is a slight projection made to receive the blows of any instrument that may be used to drive the block around when it works stiffly. Along the two lower blanks of the block slots are cut, in which traverse small projections of the console to hold the block steady. About the middle of the lower screw-sector a small hole is cut into which a small stop springs when the block is withdrawn to its limit on the console. The vent is provided with a copper bush at its forward end and a steel one at its rear.

The console is semi-cylindrical, and is hinged to the face of the breech so that when the breech-block is withdrawn it may be swung to the right and unmask the bore. It is provided with a spring stop and two small projections taking in the block, which limit the movement of the latter and hold it steady when resting on the console.

Two small pins, screwed into the face of the breech, limit the arc of movement of the crank-handle, one at the vertical point and the other 60° to the right.

A small stop attached to the face of the breech holds the crank-handle fast when the breech is closed. This stop allows the handle to pass in closing, but must be raised by hand in opening.

The gas-check is of copper, and is a fixture in its seat. It is a ring in reality, the centre being cut out to permit the passage of the charge through it in loading; the edge is turned up, forming a cup, the outer part being conical to fit the seat. The bend of the rim is quite thick, and a gutter is cut around it in order to make the powder-gas seal the joint properly. The bottom of this ring is provided with three concentric grooves to break the force of the gas that may escape through the joints. When the breech is closed the face of the block presses directly on the gas-check, and a copper ring is countersunk in the face of the block which forms the contact with the check. This ring has grooves to correspond with the grooves on the back of the gas-check.

The vent is horizontal, and is situated in the axis of the breech-block. Its outer end is formed in double-cone shape (throughout the steel bush), the small ends of the cone being joined. Percussion primers are used in connection with a spring gun-lock. (See Primers.)

Breech-Loader, Model 1864-67.

These guns are hooped like the model of 1870, but are not tubed.