United States Ordnance.

Name, Nature, and
 Classification.		Gun.FG
ABCDE
In. In.  Feet. Lbs.Lbs.Lbs.
Muzzle-loading Rifles.
  8 inch converted 136 8   15 40 17,350 3,7903,710
100-pdr. Parrott1306.4 90/199,7001,300 Directing Bar
60-pdr. ”1055.3 70/155,4001,970”
30-pdr. ” 4.2 50/123,5501,970”
20-pdr. ” 3.7 50/101,750  802”
20-pdr. Dahlgren   65.6 4   312½1,350  802”
12-pdr. bronze 553.4 310880  482Boat Carriage
Breech-loading Rifles.
80-pdr. converted 6.4 90/1910,1661,300Directing Bar
60-pdr.  ” 5.3 70/155,2701,970”
30-pdr.  ” 4.2 50/123,4281,970”
20-pdr. bronze, converted 4   612½1,340  832Boat Carriage
20-pdr. converted 3.7 50/101,740  826”
7-pdr. bronze, heavy 3  167½  535  500”
7-pdr.  ”   light 3  167½  350  450”
Smooth-bores. Weight of
Shot.
Lbs.
15-inch1461545043,00018,000 Turret Carriage
11-inch1311116616,0003,7903,710
 9-inch107 9 909,0001,300Marsilly
 8-inch 96 8 656,500  860”
32-pdr. 92 6.432.54,500  735”
24-pdr. bronze 58 5.8Shell
Guns.		1,310  730”
12-pdr. ”   heavy 55 4.6760Boat
482		Field
487
12-pdr. ”   light 50 4.6430233381

Name, Nature, and
 Classification.		ABCDE
Lbs. Lbs. Ozs. Lbs. Feet. Foot Tons.
Muzzle-loading Rifles.
  8-inch converted18010035 1,450 2,627
100-pdr. Parrott100311151,080  810
 60-pdr.  ”  4822 61,320
 30-pdr.  ”  2918 3¼
 20-pdr.  ”  18013 2
 20-pdr. Dahlgren 1810 2
 12-pdr. bronze 1208 1
Breech-loading Rifles.
 80-pdr. converted 80311151,250
 60-pdr.   ” 50  6
 30-pdr.   ” 30  3½
 20-pdr. bronze, converted  1808 2
 20-pdr. converted 20  21,070
 7-pdr. bronze, heavy  7  11,087  63
 7-pdr. bronze, light  7  ¾1,087  63
Smoth-bores.
15-inch3521301001,6007,997
11-inch13660 301,0621,300
 9-inch 7430 181,820  847
 8-inch 58111 7
32-pdr. 27014 6
24-pdr. bronze 2310 2
12-pdr. ”   heavy 1210 1
12-pdr. ”   light 1210 ½

GUNS.

In the United States Navy both smooth-bores and rifles are used, and of the latter both muzzle and breech-loaders.

Smooth-Bores.

15-inch Rodman Gun (Smooth-Bore).

9-inch Dahlgren (Smooth-Bore).

The smooth-bore guns used form a complete range of calibres from the 15-inch to the 6½-inch. The turret-guns, which are exclusively of the 15-inch pattern, are of the Rodman type of construction, of cast-iron, being cast on a core and cooled from the interior. The exterior surface shows no sharp angles and no muzzle-ring, the general shape being that of a bottle with a rounded base. The chamber of the gun is of two types, cylindrical and conical, in accordance with different dates of fabrication. The 11-inch guns are used exclusively for pivot-guns of first and second class corvettes, and it is this calibre that is being converted into 8-inch rifles, the intention being to so transform all of this type. These guns are of the Dahlgren type of construction, being similar in shape to the 15-inch (with the exception of having a swell at the muzzle), but solid cast. These guns all have conical chambers. The 9 and 8 inch and 32-pdr. are broadside-guns, and are similar in construction to the 11-inch. The 24-pdr. and two classes of 12-pdrs. are of bronze, having a conical exterior surface. These guns are used as light upper-deck guns and boat-guns.

12-pdr. Bronze (Smooth-Bore).

100-pdr. Parrott M. L. R.

20-pdr. Bronze M. L. R.

12-pdr. Bronze M. L. R.

Rifled Guns.

The muzzle-loading rifled guns are of three patterns.

1st. The 8-inch converted. These guns are all converted from the 11-inch smooth-bore on the Palliser system ([see page 217]), the length of bore being slightly increased by cutting back at the breech.

2d. The Parrott type, a compound gun consisting of a cast-iron body with a coiled wrought-iron hoop over the powder-chamber. These guns were introduced into the service in 1860, contemporaneously with the first development of rifled guns in Europe.

As early as 1862, guns of this type with a calibre of eight inches were in active service, being at that time as powerful as any guns in the world. The 8-inch calibre has never been extensively used in the service, and is at present obsolete.

3d. The Dahlgren type of bronze muzzle-loaders. The 20-pdr. gun of this type is similar in shape to the general smooth-bore type, slightly modified. The light calibres are similar to their corresponding smooth-bores.

8-inch Converted M. L. R.

Breech-Loaders.

3-inch Boat-Gun (R. B. L.).

The breech-loaders with the exception of the bronze and steel boat-guns are as yet entirely converted from the muzzle-loaders of the Parrott type. In this conversion, the coiled hoop is removed, the cascabel is cut off to the powder-chamber, and the rear end of the bore as far forward as the trunnion is reamed out for the insertion of a steel tube, having a heavy screw-thread at its rear end by which it is secured in the casing. The old rifling is then carried through this tube, leaving the calibre unchanged. The coiled hoop is replaced by another of similar type, but covering a longer space. The breech mechanism is of the French type, with Broadwell steel gas-check fixed in its seat in the gun. The breech-block is provided with a steel nose-plate of the diameter of the face of the block, and having a copper ring countersunk in its forward face to form a bearing surface against the rear of the gas-check. The nose-plate is secured to the block by a long tenon which passes through the axis of the block and is secured by a nut at the rear. The vent is bored axially through this tenon, and is of two types, corresponding to date of fabrication, for preventing back-fire. In the first, a small steel plate covers the forward end of the vent, being loosely secured, so that on firing the flame escapes past the edges of the plate, but the back pressure holds the plate close over the vent; the action being precisely similar to that of an ordinary valve. In the other type, the forward part of the vent is reduced in size until just large enough to give free passage to the flame, giving it a needle-point, which causes the flame to pierce well into the cartridge. The back pressure is neutralized in this manner, as it reacts before the forward flame pressure is relieved. It is intended to so modify the firing arrangement as to use percussion primers, the gun-lock forming the mask to the vent. The crank is double, there being a vertical arm having at its upper extremity a crank and a pinion working in a rack on the face of the breech. The swinging tray for the breech-block is hinged at the right side of the breech, while at the left side is hinged a loading-tray having a sliding guard on it. The projectile being placed on this guard and the tray swung around to face the bore, on pushing forward the projectile the guard also enters the breech-block seat, bringing up against the gas-check, and thus guarding both the check and the screw-threads. In the boat-guns there is no loading-tray, the remainder of the breech mechanism being of the same type. Boat-guns are both of steel and bronze, being in both cases made of a single block.

Grooves.

The grooves are of two types. Those for the Parrott and converted guns are of the plain rectangular type, the rule for their number and size being that they shall be uneven in number to bring a land opposite a groove; lands and grooves shall be equal in width, and grooves for all calibres shall be the same depth—¹/₁₀₀ of an inch. Increasing twist. The Dahlgren type of groove is similar to the modified French groove ([see plate, page 187]), there being three only of a regular twist. These grooves are found only in the Dahlgren muzzle-loading bronze boat-guns.

Parrott Groove.

Dahlgren Groove.

CARRIAGES.

Naval gun-carriages are built of plate-iron, although there are still a few wooden carriages and slides for pivot-guns. Breechings are used with broadside-carriages, except in the directing-bar type.

Boat-Carriages.

As yet the designs for an iron boat-carriage for the breech-loading gun are not finished. The wooden carriage in use consists of a double wooden slide, the bed, or lower slide, having pivot-centres in front and rear and being slotted through the centre for the compressor. The upper slide traverses freely on the lower one, having a piece projecting from its lower face into the slot in the lower slide to act as a guide. A second heavy piece, used as a compressor, travels along the lower face of the slot, and is held in position by screw-handles working on threaded shafts which are tightened or loosened readily by hand. The upper slide holds the trunnion-rests, which are made in a single casting with a bottom plate to bolt on the slide.

Wooden Boat-Carriage.

Field-Carriages.

The field-carriages are of two types, both of iron. That for the muzzle-loader consists of a single bar to which the axle is bolted and stayed. To its lower end is bolted an iron box for a trail-wheel and a socket for a directing handspike. A small seat for the elevating-screw is bolted at its middle on top, and at the forward end is a light iron frame for holding two ammunition-boxes. The field-carriage for the breech-loader consists of two plate-iron brackets connected by the axle and three transoms. The lower part expands into a box for the trail-wheel, and the end is finished in a loop for a drag-rope. At the forward end is a lug for attaching a caisson, and a frame on the axle outside of the brackets on each side for ammunition-boxes. The elevating-screw works in a pivoting screw-box. It will be noticed that the breech-loader has trunnions, while the muzzle-loader has only a lug, making the forward ends of the two carriages different in construction.

Iron Field-Carriage for Muzzle-Loaders.

Broadside Marsilly Carriage.

The Marsilly or rear-chock carriage is the type used with the broadside smooth-bore guns. It consists of two plate-iron brackets with a transom across the front ends and a bed-plate in the rear, giving a support for the elevating-screw, and being provided with two brass friction-shoes resting directly on deck. Holes are cut in the brackets to lighten them. A wooden breast-sweep is bolted to the transom, and there are four bolts for hooking tackles, one at each end and one at the rear of each bracket. This carriage differs from European ones in the point of not having the breeching attached to it; the latter is secured to the gun.

Broadside Directing-Bar Carriage.

Broadside Marsilly Carriage. (Elevation.)

Broadside Marsilly Carriage. (Plan.)

DIRECTING BAR CARRIAGE
FOR
60 Pdr.

(With Circular Brake Compressor.)

The directing-bar carriage is a broadside-carriage which combines the compactness of broadside types with the advantages of pivoting and checking recoil by friction instead of breechings. The top carriage is similar in type to the Marsilly, differing only in its attachments. Instead of using an elevating-screw (which with breech-loaders of medium calibre is unsafe), elevation is secured by geared racks. A rack is secured to each side of the gun and travels in guides in a similar manner on both sides; whilst, however, there is a clamp to each rack, there is but one hand-wheel for elevating, on the right side of the carriage. Just in rear of the truck-axle, a heavy axle is secured in the brackets, carrying on its centre a large cogged wheel, and just inside the left bracket a friction-drum with a gun-metal friction-band worked by a lever outside the bracket. The lever is held in any desired position by a rack, thus regulating compression. A stationary double block is secured to the transom, and a single bolt to the rear of the bed-plate, for convenience in hooking a tackle. The directing-bar consists of a long I iron having a pivot-centre near each extremity and eye-bolts at each end for hooking training-tackles. A treble block fixed at its forward end serves with the double block on the carriage for reeving an out-tackle. Along the centre of the bar a metal rack is bolted, in which the cogged wheel of the carriage travels. About three quarters of the distance to the rear are secured two railroad buffers, which may be shifted or removed at will. The carriage rests with its trucks and chocks on deck; when running in and out the chocks may be lifted from the deck on a roller handspike, and in shifting from one port or pivot to another the carriage may be run over one of the pivot-centres and then lifted with the bar entirely clear of the deck.

Iron Pivot-Carriage and Slide
for 11-inch Smooth-Bore.

The carriage consists of two plate-iron brackets with one transom and two bottom plates connected by angle-irons to the brackets. The forward trucks are permanently in action, the rear ones being mounted on eccentric axles. At the rear of the brackets are loops for the in and out tackles, and secured to the rear bed-plate are loops for a preventer-breeching. Two projecting lips protrude from the forward bed-plate beyond the brackets, forming seats for a screw-compressor. The slide is made up of two heavy double T bars connected by bottom plates and rods. It is mounted on eccentric rollers, and both the forward and rear pivot-centres are in the bed-plates. The compressors (one on each side) are of the ordinary screw-press form, composed of a wrought-iron frame having a lip on its inner lower side which takes under the slide-bars, whilst a screw in the top of the frame seats on the projections of the carriage. This type of slide and carriage is going out of use.

Iron Pivot-Carriage with
Central Recoil Check.

This carriage is the same in general principle as the ordinary pivot-carriage, the main modification being in the arrangement for checking recoil. A worm-shaft, attached to the transom of the carriage and worked by a hand-wheel outside the left bracket, gears in a large cogged wheel just outside the transom. This wheel has at the lower end of its axle a screw-sleeve operating a friction-plate which seats against two heavy bars secured to the slide. Railroad buffers are also fixed at each end of the slide.

Central Recoil-Check Carriage.

Geared Broadside-Carriage and Slide
with Hydraulic Recoil Check.

The carriage is very low, its bottom plates coming down inside the slide-rails, which are given a slope to the front. The slide is centre-port pivoting. The carriage is run out and in either by tackles or gearing. For the latter, long screw-shafts are fixed outside of the slide-rails on each side, geared by mitre-gearing to large cogged driving-wheels on the rear of the slide. A long lever is pivoted in wake of the trunnion-sockets, carrying at its lower end a half screw-sleeve. By heaving out on the lever, the sleeve engages in the screw-shaft and the gun is drawn in or out. The recoil cylinder is of the ordinary type, but provided with a circulating pipe and balanced valve by which the oil passes from one end to the other. The valve may be regulated for any desired amount of recoil. The training-gear is of the ordinary type, working a longitudinal shaft having on its outer end a cogged wheel to gear in a metal rack just inside of the rear slide-rollers.

Ericsson’s Broadside-Carriage and
Slide with Friction Recoil.[8]

The recoil arrangement of this carriage is made up of two plates operated by a lever, and jamming between them a flat plate attached to the carriage. The carriage is run in and out by gearing, the driving-wheel engaging in racks inside the slide-rails. The training-gear is of the ordinary type, but gears directly into the slide-rollers, whose middle sections are cogged, the middle section of the circle or races being cut in a rack.

Geared Carriage and Slide with Hydraulic Recoil.

Ericsson’s Turret-Carriage.

The slide of the turret-carriage consists of two bars built into the turret. The carriage is made of double plate-iron worked on a frame. The compressor is the original of the Elswick compressor ([see page 201]), working on the same principle. The gun is run in and out by means of a large cogged driving-wheel gearing in a rack underneath the slide.

Ericsson’s Turret-Carriage. (Top.)

Ericsson’s Turret-Carriage. (Bottom.)

Friction-Drum Recoil-Check Carriage.

The carriage and slide are similar to those of the 11-inch iron pivot-carriage, except with regard to the recoil check, which is exactly the same in principle as that of the directing-bar carriage.

Ericsson’s Friction Recoil Carriage.

GUNPOWDER.

Cubical Powder.

Hexagonal Powder.

Gunpowder is classed in accordance with its size of grain as follows:

Hexagonal
Cubical		notless than70normore than 75grainsto the pound.
Mammoth””0.5””1 inchmeasurement.
Rifle””0.3””0.5””
Cannon””0.1””0.3””
Torpedo””0.1””.15””
Small-arm””0.05””.06””
Shell”” .02””.06””

PROJECTILES.

The projectiles used with both smooth-bores and rifles are shot, shell, shrapnel, and case-shot.

All smooth-bore projectiles are of cast-iron.

All rifle projectiles except the 8-inch shot are common cast-iron; the shot are chilled-headed.

100-pdr. Parrott-Shell.

8-inch Shell.

8-inch Shot.

8-inch B. L. Shell.

Rifled projectiles for the boat-guns (B. L.) are provided with rotating grooved belts cast on them. They also have a rear centring ring. The rotating-rings for the larger calibres are brass rings screwing on the base of the projectile, and having an expansion groove or cup on the rear end. In the Parrott projectiles the ring is cast on the base around a heavy dovetailed score, having jogs to prevent the ring turning on the base of the shell.

The shrapnel for the boat-guns is of the simplest description, having a thin shell and a central powder-chamber throughout its length. Shrapnel for the heavy calibres is similar to the English type. Case-shot is of the ordinary construction.

12-pdr. Smooth-Bore Shrapnel.

3-inch B. L. Shrapnel.

Fixed Charge
for Boat-Gun.
(Shell and Cartridge.)

FUSES.

Navy Time-Fuse.

The fuses used in the navy are both time and percussion. There are three types of time fuses. The navy time-fuse, used in rifled and smooth-bore projectiles, consists of a brass fuse-case pierced by a centre hole, the bottom of which is closed by a small leaden plug simply jammed into place, called a safety-plug. On the top of this is the column of fuse composition driven in a paper case. Over this screws a small metal plug, called a water-cap, having angular passages cut through it to prevent the passage of water to the flame. These holes are filled with igniting composition. Over the water-cap is secured a leaden patch, sealing the fuse. This patch is torn off when the projectile is put in the gun; the flame of discharge ignites the composition, and the projectile starting from its seat drives the safety-plug out of its place into the shell, leaving the passage clear for the flame.

The Bormann fuse is used with the smooth-bore shrapnel. In this, the composition is driven in a horizontal cavity opening into a centre magazine. The top of the fuse is sealed, and its periphery marked to fractions of seconds. When inserting the projectile this fuse is cut, laying the composition bare at the desired time.

Bormann Fuse.

Boxer Time-Fuse.

Schenkl Percussion Fuse.

The Boxer fuse is a wooden-cased fuse similar to its English original.

There is but one type of percussion fuse used in the service. It consists of a brass case containing a small iron hollow cylinder filled with composition, and having at its head a small anvil on which an ordinary percussion-cap is fitted. This cylinder is suspended midway of the case by a small brass screw through the wall of the case. The top of the fuse is closed by a small screw-cap, one side of which is hollowed in a small cavity. Ordinarily this cap is screwed in place with the cavity turned downward, so that in case the cylinder breaks from its fastening the cap cannot be struck as it enters the cavity, while the shoulders bring it up before striking. To prepare it for firing, the cap is unscrewed and reversed, putting its flat side down. When the time-fuse is used in rifled shells, the safety-plug is removed before inserting the fuse.

PRIMERS.

Both percussion and friction primers are used. The percussion primer consists of a quill tube, the upper end of which is split and spread out to form a wafer. The body is filled with fine powder, the lower end being sealed with shellac, and the wafer is filled with detonating composition, covered and sealed with shellac.

The friction primer is a quill tube filled with fine powder, and having in its head a wire igniter in contact with detonating composition. The end of the wire is twisted into a loop for the purpose of hooking a firing laniard. A small preventer-loop is attached to the primer, hooking over a small pin just forward of the vent.

Percussion Primer.

Friction Primer.

LOCKS.

Percussion-locks are used with all smooth-bores. They are of the ordinary type of heavy brass gun-locks, the pivot-hole being slotted so that in firing, after the lock strikes the primer it is drawn clear of the vent.

SIGHTS.

The smooth-bore broadside-guns are provided with centre-breech and reinforce sights, pivot-guns with centre and tangent sights, and the rifled guns with tangent-sights. The smooth-bore breech-sights are rectangular bars shipped with an angle to the rear so that two sides may be seen. These sights are marked on one side for ordinary and on the other for heavy charges, corresponding to shot and shell. The reinforce sights are of the ordinary pattern. The Parrott tangent-sight does not slide in a sight-box, but has a stem which seats in a casing. It is cylindrical, and the sight-notch, fixed to a ring, slides up and down the sight-bar. The sight-notch itself is a small capstan-head having four radial notches, and working on a screw perpendicularly to the sight-bar to allow for drift. The tangent-sight for the 8-inch M. L. R. is set at a permanent angle of deflection of 1° 50´, and is provided with a sliding leaf. The graduation on all sights except the Parrott rifles and the boat-guns is in hundreds of yards. In the remainder it is in fractions of degrees.

MACHINE-GUNS.

The Hotchkiss Revolving Cannon.

The Hotchkiss Revolving Cannon.

This gun is introduced into naval services with the especial objects of, first, repelling torpedo and boarding attacks; second, for use against light merchant vessels where a light, long-range artillery fire is most effective. The gun has five barrels, and can be fired at a rate of from 60 to 80 shots per minute without forcing. Its ammunition is shell and case-shot, the weight of projectile ranging from one and a half pounds in the light calibre to four pounds in the heavy one. The extreme range is about 4500 yards. The barrels are assembled about and revolve around a central axis, the cartridges being fed through a chamber in the left upper side of the breech-casing. There is but one lock, and each barrel fires once during a revolution. The cartridge on falling into the chamber is carried forward by a cam into its barrel, being pushed close home and receiving good support when passing in front of the firing-pin. The latter is retracted by a cam, plunging forward as the centre of each cartridge comes in front of it. The rim of the cartridge-case is then seized by an independent extractor, withdrawn, and dropped to the ground. Although the crank is turned steadily, there is a certain amount of lost motion in the revolution of the barrels. This takes place as the cartridge reaches the firing-point, and during this short time of rest one cartridge is fired and another empty case is ejected. No elevating-screw is used with this gun. It is mounted on trunnions in a saddle, and projecting from the rear of the breech-case is a wooden shoulder-piece, while underneath is a handle to allow a support with the left hand. The cartridges are permanently attached to the rear of the projectiles. The shells are of steel with a percussion fuse. The barrels of the gun are made of Whitworth compressed steel of the finest quality. This gun has up to the present time proved the most effective torpedo-gun in existence. Its only rival at present is the Nordenfeldt gun, which is not yet thoroughly developed.

Chamber. (Longitudinal Section.)

Chamber. (Vertical Section.)

The Gatling Gun.

Long Pattern.

Short Pattern.

This gun, which has as yet been unequalled as a mitrailleuse, finds a place in the armament of nearly all the navies of the world. Hitherto the object of the gun in naval use has been simply to aid the small-arm fire whenever the latter was made necessary, but at present it is the design to increase the calibre of the gun so as to enable it to fire projectiles of two or more pounds. What modifications will be required in the present type of gun are not as yet known; but although the Gatling and Hotchkiss guns are both American inventions, they must not in their present stages of development be considered as rivals. The Gatling is as a rule confined to the use of small-arm ammunition; on the other hand, the Hotchkiss is to be in reality classed with boat-guns.

Lock, Extractor, and Breech-Cover.

Breech Mechanism.

Chamber.

The Gatling has ten barrels grouped about a central axis. Each barrel is provided with its own separate lock and extractor, retracted by a cam, the barrels being each fired as it comes to a certain point. The speed of firing can be carried as high as between 400 and 500 cartridges a minute without much forcing. There are two patterns of this gun, known respectively as the long and the short gun, the latter being designed especially for use in ships’ tops, while the former is used in landing and long-range firing. The cartridges are fed to the gun in tin cases holding 40 each, and which are rapidly put in position and changed so that there is no especial time lost in removing one case and shipping another. In case that one barrel should become fouled or a lock be broken, the lock can be extracted very quickly and so no hindrance is offered to the working of the mechanism, as cartridges dropping into the faulty chamber are carried around and dropped out without being fired. Notwithstanding the great rapidity of the fire there is no danger of the barrels becoming too much over-heated, and the great difficulty experienced in most guns of the mitrailleuse pattern of sticking and refusing to work, through the expansion of the barrels and mechanism due to the heat of rapid firing, is either fully avoided or compensated in the Gatling.

Barrels, Chamber, and Revolving-Gear.

Frame and Covered Breech.