Ordnance Instructions for the United States Navy.

Chapter I: Ordnance and Ordnance Stores (2)

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32. The pressure to be applied in the water-proof will be two atmospheres, or thirty pounds to the square inch.

The penetration of water in this proof through the metal of the piece, in any place, will cause the rejection of the gun; and if, on examination after the water-proof, there shall be any defects indicated by weeping or dampness in the bore, the gun shall be rejected.

The water-proof is alone to be depended on to detect minute clusters of cavities in the bore, which for this purpose should be perfectly dry, and examined by sunlight. All inspections, consequently, should take place in fair weather, and when the temperature is above the freezing-point.

MARKING GUNS.

33. Guns for the naval service, received by authority of the Bureau of Ordnance, are to be marked in the following manner, viz.:

On the cylinder, in the line of sight near the sight-mass, all accepted guns are to have stamped an anchor two inches long.

Drawings of these stamps will be furnished by the Bureau of Ordnance.

On the base ring or line, the initials of the foundry, the register number, and the weight of gun in pounds.

On the right trunnion, the calibre and year of fabrication.

On the left trunnion, the letter P. and the initials of the inspecting officer; all the above in one-inch letters.

On the upper jaw of the cascabel, the preponderance in pounds to be stamped lightly with half-inch figures.

On the end of the upper jaw, the cascabel block and head of the pin, the foundry number in quarter-inch figures.

The foundry number is also to be marked on the right rimbase.

Guns rejected for imperfections of any kind will have the letter C. stamped on the anchor, so as to partially obliterate it.

The founders are to be dissuaded from selling such guns to other parties, and required to break them up.

Guns rejected for such defects as render them dangerous to those who fire them, should be irreparably mutilated, with the consent of the founder.

EXTREME PROOF OF TRIAL-GUNS.

34. The extreme proof of guns intended for trial of metal, subject to such modifications by the Bureau as future experience may dictate, will be conducted as follows:

A suitable 'butt' shall be erected to arrest the flight of the projectiles used in proof, and to admit of their easy recovery, and a bomb-proof, readily accessible, for the protection of the firing party.

When practicable, the 'butt' should be made thick enough to allow the shot to just pass through, and be stopped by another beyond it, without penetrating the latter; this is, for XI-inch, about 12 feet.

With care, it is estimated that 130 shells may be fired 1,000 times, at the rate of one hundred rounds, per day.

After undergoing the ordinary proof established for its calibre and class, the gun selected for extreme proof shall be subjected to at least 1,000 rounds with service charges.

It may be fired from the skids, or suspended, as the Bureau may direct.

During the trial the gun shall be frequently and critically examined, inside and out, for cracks or defects, especially about the interior orifice of the vent, of which impressions are to be taken in wax at regular intervals, in the manner prescribed on page 16, or in such other manner as the Bureau may direct. If they show that the vent is corroded in furrows, and enlarged considerably in diameter at its junction with the bore, a permanent impression is to be taken in lead, to show the conical enlargement. The following manner, practised at the Experimental Battery at Washington, is recommended:

IMPLEMENTS REQUIRED.

35. 1. A soft wire about 0.07 in. in diameter, and 3 or 4 fathoms long.

2. A lever about twice the length of the bore, and about 3 inches in diameter, and shod to suit the curve of the bore nearly.

3. A small button of soft lead, judged to be of sufficient size to fill the vent at least one inch from the bore. This is to be pierced lengthwise to receive the wire.

TO TAKE THE IMPRESSION.

36. Shove the wire through the vent; let it pass along the bore and out at the muzzle; put it through the leaden button and tie a knot at the end. Draw the wire back through the vent until the leaden button is introduced firmly into the inner orifice.

Apply the lever, making its shoe bear on the button, and force it well in by repeated blows, the muzzle being the fulcrum. This done, disengage the button by pushing in the priming-wire.

In taking impressions of the vent and cracks, each button in turn is used as a pattern for moulding its successor, allowing for the progressive enlargement of the vent, or the cracks emanating from it. When the crack shows itself, the head of the button should be so enlarged as to include it.

These examinations should take place after every twenty fires, at least, and more frequently when any unusual enlargement of the vent or extension of cracks shall be developed, and indicate its speedy destruction.

Before each examination the bore of the gun is to be carefully washed and dried.

In recording the measurements of the bore in extreme proof and after service, distinguish between "indentation," which is the depression at the "seat of the shot," which is always below, and the "wear of the bore," which is generally above, and increase of bore, or "enlargement" from any other cause.

When from the appearance of the bore at the interior orifice of the vent, and especially when a crack or cracks appear to be extending rapidly, the vent so enlarged may be filled with melted tin, zinc, or Babbitt metal,--a tight-fitting sponge-head being pushed to the bottom of the chamber to close the interior orifice,--and the other vent be drilled through for the purpose of continuing the firing.

The precise time at which this is to be done will vary, according to circumstances; such as quality of metal, charge, and elevation.

The endurance of a smooth-bored gun with service charges may be surely predicted by observation of the progressive wear of the interior orifice of the vent.

There are certain general forms in which this enlargement takes place. They may be classed as triangular, lozenge, quadrilateral, star, circular, and elliptic. (See Plate.)

With the ordinary central vent, when subjected to a rapid, continuous fire, the enlargement usually takes the form of an isosceles triangle, the apex of one of the angles towards the muzzle, and the other two perpendicular to it.

With the lateral vent of the Dahlgren system it usually takes the lozenge form, the cracks extending from the opposite angles lengthwise of the bore.

With those rifled cannon in which the vent is bouched, the cracks appear around the bouching; and although the bouching preserves the vent, yet the formation of fissures around the enlarged orifice, when once commenced, causes a greater tendency to rupture. With the vent not bouched, the wear in rifled cannon is about double that of the smooth-bore.

So long as the wear of the vent is regular and without cracks, a mere enlargement is not indicative of danger; but when it reaches a diameter of four-tenths (.4) of an inch the vent should be closed and a new one opened.

A gun of large calibre should not in service be expected to endure more than 400 or 500 rounds before it will be necessary to open the new vent, which, however, will be of no advantage, unless the old one be closed at its interior orifice, on which the gases would otherwise continue to act as a wedge.

The first distinct appearance of the cracks, as shown by the button, is the proper limit.

After the gun bursts, make a sketch or draft showing lines of fracture, and reserve specimens to be sent to the Ordnance Yard at Washington for trial of density and tensile strength; and, if practicable, a photograph should be taken.

PREPARATION OF GUNS FOR SERVICE.

37. After the guns have been received at the Navy Yards it is necessary to adjust the sights, and, in the guns of the Dahlgren pattern, cut the screw hole in the cascabel.

CUTTING THE SCREW-HOLE.

38. The boring and screw-cutting machine is a convenient portable hand drill-press, the use of which is readily understood by any machinist.

The gun being carefully levelled, and the trunnions placed horizontal, the position of the centre of the screw-hole, which in the guns of the Dahlgren pattern is tangent to the radius of the breech, is marked on the neck of the cascabel with a centre punch.

The machine is placed on the cascabel, the boring shaft inserted in the hollow leading bar, and its movable centre placed on the mark. The instrument is then set vertical, by a spirit-level on the cogged driving-wheel, and the four pairs of set screws on the clamp-head embracing the cascabel.

The centre is then removed, and a drill inserted in the lower extremity of the boring-shaft, which, being held firmly by a shoulder and turned by a four-armed wrench, while pressed up to the metal by slowly turning the cogged driving-wheel, cuts the hole. This is successively enlarged, by two or more counterbits, to the size of the body of the screw.

The cutter is then inserted in the leading bar, and the thread cut.

ADJUSTMENT OF THE SIGHTS.

39. The bore having been thoroughly cleaned, the axis is levelled by a spirit-level; this may be very conveniently done by the aid of the levelling-bar. The axis of the trunnions is to be laid horizontal, either by placing a small level on the trunnions, or, as more exact, by using the trunnion-square. If the trunnion-square is used it will be proper to verify the position of the line of sight, which is frequently incorrectly placed at the foundries.

The breech-sight is then to be adjusted.

A brass head or tompion, fitted with a vertical arm, on which there is a ledge for a spirit-level, is then introduced into the bore, and the arm placed vertical by the spirit-level and a tangent screw.

The arm is pierced on its centre line with two holes--one at the height of the prescribed diameter of the muzzle, the other at a height equal to the proper distance of the bottom of the sight-notch from the axis of the bore. A waxed thread or fine wire, being stretched from the upper hole to the centre of the sight-notch, will coincide with the line of sight traced on the swell of the muzzle, the top of the reinforce sight-mass, and the base-line, if they are correctly placed. It will also be parallel to the axis of the bore if the adjustment of the breech-sight is exact, and the top of the reinforce-sight is made to coincide with it.

This is, however, seldom the case, and after the adjustment of the reinforce-sight it is necessary to verify it.

This is done by the levelling-bar--a square steel bar with parallel faces, somewhat longer than the distance between the sights, the rear end of which is bevelled at 60 deg. (the angle at which the sight is placed).

The outer end of this bar is placed on the reinforce-sight, which has been previously adjusted to the proper height, and the bevelled end in contact with the outer face of the sight-bar. The bar is then levelled by two screws placed near the inner end, and a spirit-level on its upper surface.

If then the bottom of the sight-notch coincides with the bottom of the bar, the line of sight is parallel to the axis; otherwise, the reinforce-sight or the sight-bar must be lowered until coincidence is obtained.

A centre line on the bar verifies the coincidence of the line of sight, and also the motion of the sight-bar in the vertical plane. The bevel verifies the angle of the bar; and the distance between the outer faces of the sight-notch and of the reinforce-sight, being also marked on the levelling-bar, verifies this adjustment.

Another method is sometimes and more advantageously used in adjusting the sights of guns which have not been turned.

Two iron or wooden disks are turned to the exact diameter of the bore, and placed on a rod two or three feet longer than the bore. One of the disks is placed near the bottom of the bore, the other just within the muzzle. On the part projecting beyond the muzzle there is a double square, each arm of which is divided into equal parts and traversed by a fine slit.

The square being set vertical by a spirit-level or plumb-line, and a waxed thread or wire stretched taut from the outer arm through the slit, cutting equal divisions on each, and passing through the centre of the slit, it is evident that a line of sight is obtained through the centre of metal and parallel to the axis of the bore.

This method has the advantage of adjusting the sights in any plane parallel to the axis, as in the case of the side-sights of rifled and other cannon.

ADJUSTMENT OF THE SIDE-SIGHTS.

40. The gun having been levelled, and the trunnions placed horizontal, a centre line is to be drawn on the top of the left (or right) rimbase.

The support for the sight is then to be fitted to the breech, at the distance from this line marked on the pattern-sight for its calibre, with the bottom of the sight-notch in the bar, exactly the height of the front sight (one inch) above the upper surface of the rimbase; the sight-bar perpendicular.

It is advisable to place a very thin sheet of rubber under the support, to prevent the heads of the screws from being jumped off by the vibration. The screws have the same thread as those for the present reinforce-sight.

After the breech-sight is adjusted, a parallel to the axis of the bore is to be drawn in the usual manner, and the front sight screwed in on the rimbase.

Some trifling adjustment may then be required, to bring the height of the top of the front sight and the bottom of the sight-notch parallel to the axis of the bore in both the horizontal and vertical planes.

PRESERVATION OF GUNS.

41. Guns received at Navy Yards are to be carefully placed on the ranges of masonry, capped with iron skids or bars. It is intended that these shall be so high that the guns may be rolled upon them without their trunnions touching the ground, and that the earth will not be beaten up against their muzzles by heavy rains.

42. The surface over which guns are to be stowed should be kept firm and clear of all vegetation, and for this purpose should be covered with cinders from the smiths' forges, or other substance unfavorable to or destructive of the growth of plants and grasses.

43. In stowing the guns they should be made to rest on one of the skids or bars, a little forward of the base-ring, the muzzle depressed, but not so much as to prevent the use of the sponge to clean out the gun; the axis of the trunnion of each to be inclined the same way, and just enough not to touch the adjoining gun; the vents to be upwards.

44. Before the stowage is finally made they should be carefully and thoroughly cleaned from rust and all improper coatings, and be lacquered internally and externally with such composition as may be directed by the Bureau. This should be applied, when practicable, when the guns are well warmed by the rays of the sun. The vents and all screw-holes are to be stopped with plugs made of soft wood or oakum dipped in tallow, after they have been protected by an application of beeswax dissolved in spirits of turpentine, or other composition that may be directed by the Bureau.

45. No tompions are to be put into the guns when they are stowed unless expressly directed by the Bureau; if so ordered, a score must be cut out from them on the lower side, half an inch wide and equally deep.

46. In lacquering guns care is to be taken to leave the distinguishing marks and numbers distinctly visible.

47. Shell-guns are always to be denominated by the diameter of the bore; shot-guns by the weight of their shot.

48. Guns of the same calibre and class, when it can be conveniently done, are to be stowed in the same tier or range, and those of each class belonging to or selected for any particular vessel kept together. Each tier or range of guns of a particular calibre or class is to be marked accordingly with paint on a sign-board, and the first gun of each class belonging to a vessel is to be marked with the name of the vessel.

49. The Officer on Ordnance duty will examine all the guns in the yard and on board vessels in ordinary, at least once in every two weeks, and take care that they are kept protected from rust or any other injury, and will report to the Bureau whenever any additional precautions or arrangements are required for their proper preservation, and which may not be furnished by the order of the Commandant of the Yard.

50. No cutting, boring, or chiselling of guns is to be done at any time without express authority from the Bureau.

51. No condemnation of guns or small arms belonging to the Navy is to be made, except upon surveys specially ordered, and confirmed by the Chief of the Bureau; nor of other articles which have been furnished under his authority, or by his direction, unless by surveys ordered or sanctioned by him.

52. When guns and their equipments are to be put on board vessels for their armament, the guns are to be carefully and thoroughly cleaned and examined, to see that they are in all respects in proper serviceable condition.

The vents should be examined with the vent-gauges and searchers, to see that they are clear from any substance which may obstruct the use of priming-wires and primers.

53. The carriages are also to be carefully examined, the trunnion-holes and arms of the axletrees cleaned, and saturated with boiled linseed oil, the cracks filled with putty, and rubbed smooth, and the trunnion-holes black-leaded. The iron work should be freed from rust, all screws be made to work easily, and be well cleaned and coated with proper composition.

54. The Ordnance Officers will see that the sights are properly fitted and marked for their proper guns. The greatest care should be taken that they are properly adjusted, as the efficiency of the ship depends on it, and it is difficult to detect or remedy any error after they are placed on board; that the beds and quoins are fitted and adjusted, and the quoins graduated to degrees or distances to correspond with those marked on the sight-bars. Porter's quoin is adopted for all carriages requiring quoins.

55. New guns are to have locks fitted to them before being put on board ship. Those having two lugs will have the one on the right fitted; the other is to be left solid.

56. When the guns are to be shipped for transportation merely, the same precautions are to be taken to guard them from injury as on shore, with the addition of a wad dipped into the composition which covers the bore, thrust into the muzzle, and connected with the tompion by a lanyard.

In the transportation of guns by rail--unboxed--the vents are to be plugged with soft wood, puttied over, and turned vent downwards on the trucks. All bronze howitzers transported by rail shall be boxed.

57. At the termination of a cruise the guns composing the battery of every vessel-of-war of the United States, shall be carefully examined by the Ordnance Officer of the Yard, and such others as may be directed, with the view to discover and report any injuries which they may have sustained in service, or any defects which may not have been developed in the original proof. In this examination the attention of the Inspecting Officers is to be directed to the following points, viz.:

Enlargement of the interior or exterior orifice of the vent.

Indentations or hollows produced by the shot balloting against the surface of the bore, or by the action of the gases.

Cuts or scratches in the bore, produced by fragments of broken or the roughness of imperfect shot.

Roughness or corrosion of the metal on the exterior, produced by neglect or exposure.

Similar injuries in the bore, or any enlargement of the bore, which is to be ascertained by measuring with the star-gauge, at every one-fourth (1/4) of an inch from the bottom of the cylindrical part to the seat of the shot, every inch from that point to the trunnion, thence every 5 inches to the muzzle, and the results recorded in the usual form, and reported to the Bureau, that they may be compared with those noted at the original inspection.

In rifled cannon, cracks or injuries produced by firing, or the rupture of shells, are to be sought for:--

Around and in rear of the vent bouching;

On the top of the bore, between the trunnions and reinforce band.

On the lower side of the bore, near the seat of the shot, at the junction of the lands and grooves.

Near the inside of the muzzle, caused by explosion of shells.

Care is to be taken that the distinguishing marks and numbers are always accurately noted, that the correct history of each gun may be preserved.

58. Before sailing, the Inspector of Ordnance will furnish the commander with a descriptive list of his battery, together with a statement of the number of times each gun on board has been fired, in the following form; a copy of which the commander shall transmit to the Bureau before sailing: this list shall be returned to the Inspector of the Yard to which she may return, with all additional firing noted opposite the number of each gun, certified "correct" by the commander.

In the list furnished by the Inspector, if the "number of fires" is _estimated_, it is to be entered in red ink (_See_ Arts. 62-64), and so carried forward in the subsequent returns.

NAME OF VESSEL. STATION.

_________________________________

Forwarded by _Commanding._

59. The Bureau directs that, whenever a gun is taken on board a vessel, the number of rounds which have been fired from it be ascertained by the Commander, a record made thereof, and forwarded with the descriptive list, in the above form, to the Bureau; and whenever a gun is landed or transferred to another vessel, a similar record is to be furnished the officer receiving it, which must be stated in the receipt for the gun, and a copy forwarded to the Bureau of Ordnance by the officer delivering the gun.

The Commander shall also transmit to the Bureau a quarterly return, according to the prescribed form (_See_ Appendix B, No. X.) of all firing whether with or without projectiles, in action or otherwise; noting particularly the kind of shell, species of fuze, kind, charge, and name of maker of the powder used in the gun and shell. He shall take care to note also the number of premature explosions of shells, and the point at which they take place, with the supposed causes thereof.

60. The Inspector will also furnish the commander with a set of leaden impressions of the interior orifice of the vents of the guns, secured in a suitable box, that he may be able to compare the wear and gradual enlargement. These will be transferred with the guns to other ships or when landed.

61. The protracted firing to which the Navy cannon have been subjected, and to which they will continue to be liable, renders it necessary not to exceed the number of fires designated for each vent.

These must never exceed five hundred (500) fires for each vent.

In the IX-in., XI-in., and guns of similar form, the right vent is always bored through, and the left initiated sufficiently to give it direction.

When five hundred (500) rounds have been fired from the right vent, it is to be closed by filling it with molten zinc or lead, and the left vent is to be bored, which will require a skilful mechanic.

When the left vent has been fired five hundred (500) rounds, the gun is to be disused, as it will then have been fired one thousand (1,000) times.

It may happen, from some peculiarity in the nature of the iron, that the vent may be worn to its full extent before five hundred (500) rounds have been fired, in which case the vent is then to be closed, and the other vent opened.

The gun should be frequently and critically examined inside and out for cracks or defects, especially about the interior orifice of the vent, of which impressions should be taken after every ten shotted rounds in practice, and at the close of an action.

The instrument described on p. 16 is convenient, but by no means indispensable--any small spar, such as a boat's mast, or even the rammer handle with a curved piece of wood seized to the end, will, in expert hands, take an impression of the vent or crack equally well.

62. As the best indication of the amount of firing to which any smooth-bored gun has been exposed, when it is not otherwise known, is given by the enlargement of the vent, particular attention will be paid, in the reinspection of the guns, to this point. The standard gauge will be used to ascertain the general enlargement, and the searcher to detect defects which may have been developed in firing. Impressions are to be taken of the lower orifice of the vent with softened wax, and if they show that the vent is corroded in furrows and enlarged considerably in diameter at its junction with the bore, a permanent impression is to be taken in lead to show the conical enlargement. (See mode of taking impressions, Arts. 35 and 36.)

63. When the number of rounds fired is not known, an estimate may be made from an examination of the vent by cylindrical gauges differing from each other by .01 of an inch passed through it. If the number is estimated, it is to be entered in red ink.

64. In all the guns of the Dahlgren pattern the vents are (.2) two-tenths of an inch in diameter. In all other guns .22 of an inch exterior, .2 of an inch on the interior.

Observation of the wear of the vent in proof firing of smooth-bored guns gives the following as the average diameter of the vent, after the undermentioned number of fires:

No. of rounds 100 200 300 400 500
Diameter of vent .24 .26 .30 .35 .40

These, combined with examination of the interior orifice, will enable a very correct judgment to be formed of the probable number of fires sustained and duration of the gun.

The larger the calibre and the heavier the charge the more promptly the wear is manifested on the interior and exterior.

This enlargement does not extend very far from the lower orifice until the enlargement on the exterior has reached a diameter of .3 of an inch.

65. So long as the wear is regular, and the cracks, although numerous, do not exceed .5 of an inch in length, the indications are good. If the cracks are but few or diminish in number, running into each other and extending rapidly, it is a very unfavorable sign. In the rifle cannon (Parrott's) cracks athwart the bore either running into the bouching or in the rear of it are very unfavorable to the gun's endurance.

66. Whenever any premature explosions of shells take place within the gun or near the muzzle, a careful examination of the gun shall be made; and all the circumstances of the case, together with the opinions of the commander and officers in immediate charge as to the cause thereof, reported to the Bureau; taking care to state the kind of shell and species of fuze used; the mode of loading; whether the shell was lined or coated on the interior; kind, charge, and name of maker of the powder which was used in the gun and shell.

There is reason to believe that few failures of the Parrott rifles have occurred where the guns have not been previously, or at the time, injuriously strained by the explosion of shells within the bore.

67 Whenever a gun shall give away under fire, or an accident of any kind happen to one, the Bureau desires to be immediately informed of all the facts in relation thereto.

Particular attention should be paid to the following points:

1. The manner in which the gun was loaded, stating the charge and kind of powder used, and character and weight of projectiles.

2. The condition and appearance of the gun after it gave way, and what effect was produced on the carriage by the explosion.

3. What injuries, if any, occurred to the crew of the gun or vessel.

Sketches of the gun and fragments which remain should also be sent to the Ordnance Yard at Washington for trial of density and tensile strength, accompanied by the written statement in detail of the officers in immediate charge of the gun, and if practicable a photograph should be taken.

INSPECTION OF SHOT AND SHELLS.

RULES AND MEMORANDA FOR THE GOVERNMENT OF INSPECTORS.

68. All shot and shells for the naval service must be--

1st. Made from gray or mottled charcoal pig-iron.

2d. This iron most not be blasted with anthracite coal.

3d. It must be poured into sand moulds.

69. After being cast in this manner, the shot and shells must be--

1st. Spherical.

2d. Smooth on the surface.

3d. Free from the defects named in the following rules for the use of the inspecting instruments:

FOR SHOT.

70. INSPECTING INSTRUMENTS.--One large, small, and one medium ring gauge, and one cylinder-gauge for each calibre. The cylinder-gauge shall have the same diameter as the large gauge, made of cast iron, and three calibres in length. One hammer weighing two pounds, and having a flat face and a conical point; one searcher, of steel wire, with a handle; one pair of calipers and standard scale; one cold chisel; steel punches.

71. After having been well cleaned, each shot is placed upon a table, and examined to see that its surface is smooth, and that the metal is sound and free from seams, flaws, and blisters. If clusters of cavities or small holes appear on the surface, strike the point of the hammer into them, and ascertain their depth with the searcher. If the depth of the cavity exceeds 0.2 inch, the shot shall be rejected; it shall also be rejected if any attempt is made to conceal defects by plugging or filling holes in any mode whatever.

72. The shot must pass in every direction through the large gauge, and not at all through the small one; the calipers and scale will determine exactly the difference of diameters of the same projectile.

73. The ring and cylinder gauges shall be examined before each inspection, and when found to have enlarged 0.01 of an inch, must be laid aside and marked as unserviceable.

74. The shot are next to be passed through the cylinder-gauge, placed at an inclination of about two inches between the ends, and supported in such a manner as to be easily turned from time to time, to prevent its being worn in furrows. Shot which slide or stick in the cylinder shall be rejected; the latter must be pushed out from the lower end of the cylinder with a wooden rammer.

75. The next proof of shot is to drop a few taken indiscriminately from the lot under inspection from a height of twenty feet on a solid platform of iron, or roll them down an inclined plane of the same height against a mass of iron; after which they are again examined for defects of metal.

76. The average weight of shot shall be determined by weighing at least three parcels, of from 20 to 50 each, taken indiscriminately from the lot. As many of the lightest shall be weighed separately as the inspecting officer may deem necessary, and all found to fall below the least weight allowed in the annexed table of the dimensions of shot and shells shall be rejected. Shot made of charcoal iron will be stamped with a * or "burr" near the gate.

SHELLS.

77. Shells should be cast on a half-inch hollow spindle, to allow the gas to pass freely from the core; the fuze-hole would then be sufficiently large to admit the gauge for thickness before the shells leave the foundry.

78. INSPECTING INSTRUMENTS.--In addition to the instruments for shot, there will be required calipers with steel points for measuring the thickness of the shell at points on the great circle at right angles with the axis of the fuze-hole; gauges for the thickness at and opposite the fuze-hole; a conical flat steel gauge for the fuze-hole, marked at the point to which it should enter; a pair of strong hand-bellows, with a wooden plug to fit the fuze-hole and the nozzle air-tight. (See Plate.)

INSPECTION.

79. The surface of the shell and its exterior dimensions, form, weight, and strength, are to be examined and tested as in the case of shot, and subject to all the conditions there specified.

80. The greatest care is to be taken to remove every particle of sand or fragment of iron from the interior when they are about to be loaded for service. And the Inspectors of Ordnance at foundries or Navy Yards will satisfy themselves that this has been done before accepting or preparing them for service.

81. The shell is next struck with a hammer, to judge by the ring or sound whether it is free from cracks; and the exterior and interior diameters of the fuze-hole (which should be accurately reamed) are to be verified, and the soundness of the metal about the inside of the fuze-hole ascertained. To determine the thickness of the metal, three points, at least, on the great circle at right angles to the axis of the fuze-hole are to be measured; also one at the fuze-hole and one at the bottom. No shell shall be received which deviates more than one-tenth of an inch from the proper thickness in any part.

82. The shell is next placed in a tub of water, which should be deep enough to completely cover the shell. Air is then forced by the bellows into the shell. If there are any holes in it, air-bubbles will rise on the surface of the water, and the shell shall be rejected.

83. This occasionally occurs from the escape of air from porous spots which do not extend to the interior of the shells. In this case the action of the bellows produces no increase of bubbles, which cease rising as soon as the spots or cavities are filled with water. Porous spots are also detected by their absorbing water and drying slowly when exposed to the air, and shall likewise cause the rejection of the shell.

84. The Inspecting Officers will stamp the shell at one inch from the fuze-hole with their initials, also those of the foundry at which they are cast.

The Inspector or one of his assistants must be present when shot or shell are inspected; and the stamps and marks are always to be retained in the possession of the Inspector.

85. Rejected shells are to be mutilated by chipping a piece out at the fuze-hole.

86. If, upon the inspection of shot or shells, any of them should be found not to conform strictly to these instructions or to the requirements of the contract under which they are offered for reception, the Inspecting Officer is not to receive them; but if, in his opinion, the defects, taken in connection with the general character of the articles, will not impair their efficacy or render them unsafe or hazardous, he may refer to the Chief of the Bureau of Ordnance for his decision, forwarding to him minute and full information on the subject.

87. Shot and shells shall be delivered for inspection at the places specified in the contract, at the expense of the contractor; and those which are rejected shall be immediately removed, also at his expense.

TABLE OF SHOT AND SHELL GAUGES.

88. SHOT.

DIMENSIONS, WEIGHT. | XV. |XIII. | XI. | X. | IX. | 8. | 32. |
|(Cored.)| | | | | | |
--------------------------+--------+------+------+------+-----+-----+-----+
Diameter of large gauge | | | | | | | |
for foundries. | 14.83 | 12.83| 10.83| 9.83| 8.83| 7.88| 6.28|
Diameter of small gauge | | | | | | | |
for foundries. | 14.77 | 12.77| 10.77| 9.77| 8.77| 7.82| 6.22|
Mean of gauge for | | | | | | | |
foundries. in.| 14.80 | 12.80| 10.80| 9.80| 8.80| 7.85| 6.25|
Mean weight required | | | | | | | |
of foundries. lbs.| 400. |276. |166. |124. |90. |65. |32.5 |
Least weight allowed | | | | | | | |
foundries. lbs.| -- | -- | -- | -- | -- |64.5 |32. |
Diameter of small gauges | | | | | | | |
for service. | | | | | | | |
{1st class in.| -- | -- | -- | -- | -- | 7.82| 6.22|
{2d class in.| -- | -- | -- | -- | -- | 7.80| 6.20|
--------------------------+--------+------+------+------+-----+-----+-----+

89. SHELL.

DIMENSIONS, WEIGHT. | XV. |XIII. | XI. | X. | IX. | 8. | 32. | ---------------------------+-------+------+------+------+-----+-----+-----+ Diameter of large gauge | | | | | | | | for foundries. | 14.83| 12.83| 10.87| 9.87| 8.87| 7.88| 6.28| Diameter of small gauge | | | | | | | | for foundries. | 14.77| 12.77| 10.83| 9.83| 8.83| 7.82| 6.22| Mean of gauge for | | | | | | | | foundries. in.| 14.80| 12.80| 10.85| 9.85| 8.85| 7.85| 6.25| {Proper in.| 2.85| 2.37| 2. | 1.80| 1.60| 1.50| 1.25| Thickness. {Greatest in.| 2.95| 2.47| 2.10| 1.90| 1.70| 1.60| 1.35| {Least in.| 2.75| 2.27| 1.90| 1.70| 1.50| 1.40| 1.15| Diameter of fuze-hole. | | | | | | | | {Proper and least | .65| .65| .65| .65| .65| .65| .65| {Greatest | .75| .75| .75| .75| .75| .75| .75| Diameter of large gauge | | | | | | | | for strapped. | 14.93| 12.93| 10.93| 9.93| 8.98| 7.93| 6.33| Mean weight required | | | | | | | | for foundries. lbs.| 330. |208. |127. | 95. |68.50|50. |25. | Least weight allowed | | | | | | | | foundries for | | | | | | | | any one. lbs.| -- | -- |126. | 94. |67.50|49. |24.5 | Weight of filled and | | | | | | | | sabotted. lbs.| 352. |216.5 |135.5 |101.50|73.50|52.75|26.5 | ---------------------------+-------+------+------+------+-----+-----+-----+

For gauges of boat-gun fixed ammunition, see Boat Armament of United States Navy, by Admiral Dahlgren, 2d edition, 1856.

90. SHRAPNEL.

DIMENSIONS, WEIGHT. | XV. | XI. | X. | IX. | --------------------------+-------+------+------+------+ Mean of empty case. | | | | | { Gauge in.| 14.8 | 10.85| 9.85| 8.85| { Thickness in.| 1.25| 1. | .87| .75| { Weight lbs.| 178. | 76. | 57. | 38. | Balls { Number |1000. |625. |435. |350. | { Diameter lbs.| 1. | .85| .85| .85| { Weight lbs.| 140. | 51. | 33.5 | 27. | Sulphur. lbs.| 30. | 10. | 8.5 | 7. | Bursting charge. oz.| 10. | 6. | 4. | 3. | | | | | | Weight complete. } | | | | | Weight sabotted. } lbs.| 358. |141. |101. | 75. | --------------------------+-------+------+------+------+

DIMENSIONS, WEIGHT. | 8. | 32. | 24 | 12 | --------------------------+-------+---------+---------+---------+ Mean of empty case. | | | | | { Gauge in.| 7.85| 6.25 | 5.67 | 4.52 | { Thickness in.| .69| .60 | .55 | .45 | { Weight lbs.| 29. | 15. | 11. | 6.5 | Balls { Number | 220. |235. lead|175. lead| 80. lead| { Diameter lbs.| .85| .65 | .65 | .65 | { Weight lbs.| 17. | 14. | 10.5 | 4.75 | Sulphur. lbs.| 5. | 2.25 | 1.5 | .75 | Bursting charge. oz.| 2.5 | 1.25 |450. |350. | | | | grs. | grs. | Weight complete. } | | | | | Weight sabotted. } lbs.| 52. | 32. | 24. | 12. | --------------------------+-------+---------+---------+---------+

91. DIMENSIONS OF SABOTS AND STRAPS FOR SHELL AND SHRAPNEL.

DIMENSIONS, WEIGHT. | XV. |XIII.| XI. | X. | IX. | 8. | 32. | 24. | 12. | --------------------+-----+-----+-----+-----+-----+-----+------+-----+-----+ Thickness in.| 5. | 4.50| 2.75| 2.75| 2.40| 2. | 1.50 |1.90 |1.50 | Diameter | | | | | | | | | | {greatest in.|14.25|12.25|10.50| 9.50| 8.60| 6.90| 6. |5.7 |4.60 | {least in.|14.25|12.25|10.50| 9.50| 8.60| 6.80| 5.50 |5.55 |4.40 | Depth of saucers in.| 2.50| 2.25| 1.80| 1.60| 1.40| 1.20| 1. |1.50 |1.30 | Weights lbs.| 8.90| 5.50| 2.70| 2.40| 1.85| .90| .50 | .46 | .22 | Shell-straps | | | | | | | | | | {Length in.|25.75|22.5 |17.25|17.25|14.75|13.25|10.25 |7.625|6.375| {Width in.| 1.25| 1. | .75| .75| .75| .75| .625| .50 | .375| {Tin No.| XXD | XXD | XXD | XXD | IX | IX | IC | IC | IC | Tacks No.| 20 | 16 | 12 | 12 | 8 | 8 | 8 | 4 | 4 | --------------------+-----+-----+-----+-----+-----+-----+------+-----+-----+

92. GRAPE.

| | | | | | | | |RIFLE | | | | | | | | | +-------+ DIMENSIONS, WEIGHT. | XV.|XI. |X. |IX. | 8. |32. |24.|12.|20.|12.| ----------------------+----+------+-----+-----+-----+-----+---+---+---+---+ Weight of stand lbs.| -- | 34.75|26.10|20.4 |15.7 | 8.75| | | | | Weight of balls lbs.| -- | 89.10|71.70|25.20|37.12|24.80| | | | | Number of balls | -- | 15. |15. |18. |18. |12. | | | | | Diameter of balls in.| -- | 3.55| 3.34| 2.80| 2.50| 2.50| | | | | Weight complete lbs.| -- |125.08|98.62|74.10|58.25|33.50| | | | | ----------------------+----+------+-----+-----+-----+-----+---+---+---+---+

93. CANISTER.

DIMENSIONS, WEIGHT. |XV. |XI. |X. |IX. |
----------------------+------+------+------+-------+
Windage in.| .25| .25| .25| .25 |
Height | | | | |
{Empty case in.| 15.50| 13.50| 11.75|10.5 |
{Finished in.| 14. | 12. | 10.5 | 9.5 |
Case notched, and | | | | |
turned over in.| .75| .75| .65| .50 |
Thickness of head | | | | |
{Top in.| 1. | 5/8 | 5/8 | 5/8 |
{Middle in.| 1. | 5/8 | | |
{Bottom in.| 2. | 1. | 1. | 1. |
Size of | | | | |
{Rod in.|13/16 | 1/2 | 1/2 | 1/2 |
{Nut {diameter in.| 2.75| 1.75| 1.75| 1.75 |
{thickness in.| 1.50| 1. | 1. | 1. |
{Bale in.| 1/2 | 3/5 | 5/8 | 3/5 |
Metal and thickness | | | | |
{Iron No.| 20. | 25. | 25. | 25. |
{Tin No.| -- | -- | -- | -- |
Balls | | | | |
{Number |600. |315. |290. |230. |
{Diameter in.| 1.30| 1.30| 1.30| 1.30 |
{Weight lbs.|150. | 85. | 70. | 65. |
Weight finished lbs.|207. |120. | 98. | 70. |
----------------------+------+------+------+-------+

DIMENSIONS, WEIGHT. |8. |32. |24. |12. |
----------------------+------+------+-----+-----+
Windage in.| .25| .25| .15| .15|
Height | | | | |
{Empty case in.| 9.75| 8.65| 5. | 3.85|
{Finished in.| 8.75| 7.75| 6. | 5. |
Case notched, and | | | | |
turned over in.| .50| .45| 4.65| 3.52|
Thickness of head | | | | |
{Top in.| .75| .50| .35| .3 |
{Middle in.| | | | |
{Bottom in.| .75| .50| 1.90| 1.90|
Size of | | | | |
{Rod in.| | | | |
{Nut { diameter in.| | | | |
{thickness in.| | | | |
{Bale in.| | | | |
Metal and thickness | | | | |
{Iron No.| | | | |
{Tin No.| XXD | XXD | IC | IC |
Balls | | | | |
{Number |162. |100. |39. |39. |
{Diameter in.| 1.30| 1.30| 1.30| 1. |
{Weight lbs.| 45. | 28. |12.5 | 5.85|
Weight finished lbs.| 50. | 30. |14.55| 7.75|
----------------------+------+------+-----+-----+

NOTE.--Bottom of XV-inch canister, of two thicknesses of oak, ash,
or beech, crossing each other; put together with wrought-iron
nails, clinched; spindle riveting on the bottom through a 3 inches
square plate, 1/4 thick; cast-iron hexagonal nut, with
wrought-iron bale.

For XI, X, and IX-inch, bottom-head one thickness of one-inch oak,
ash, or beech; spindle riveting on a plate 1-1/4 inches wide, by
1/4 thick, running across the grain the whole width of bottom,
with a rivet at each end of plate.

Top and centre heads of all made of white pine.

Iron cases to be well painted inside with red before filling.

94. Shot of the first class, or which do not exceed 0.18 of an inch windage, are to be entirely black, and those of the second class, having from 0.18 to 0.20 of an inch windage, to be marked partly white. Each class is to be piled and kept separate from every other. Both classes are to be considered and supplied as "serviceable shot;" but are to be stowed separately on board ship, and the returns to the Bureau are to show the number of each, respectively. The number of those having more than 0.20 of an inch windage are to be reported and retained until special orders may be given for their disposition. In case any should be taken as the foundation for piling serviceable shot, they are to be painted entirely white and their number returned as unserviceable.

PILING OF BALLS.

95. To find the number of balls in a pile--Multiply the sum of the three parallel edges by one-third of the number of balls in a triangular face.

In a square pile one of the parallel edges contains but one ball; in a triangular pile two of the edges have but one ball in each. The number of balls in a triangular face is x(x+1)/2; x being the number in the bottom row. The sum of the three parallel edges in a triangular pile is x+2; in a square pile, 2x+1; in an oblong pile, 3X + 2x-2; X being the length of the top row, and x the width of the bottom tier; or 3m-x+1; m being the length, x the width of the bottom tier.

If a pile consists of two piles joined at a right angle, calculate the contents of one as a common oblong pile, and of the other as a pile of which the three parallel edges are equal.

96. TABLE GIVING THE NUMBER OF BALLS IN A TRIANGULAR PILE, THE BASE OF WHICH IS X.

VALUE OF | VALUE OF | VALUE OF | VALUE OF | VALUE OF | -----+------+-----+------+-----+------+-----+------+-----+------+ X. | S. | X. | S. | X. | S. | X. | S. | X. | S. | -----+------+-----+------+-----+------+-----+------+-----+------+ 1 | 1 | 6 | 56 | 11 | 286 | 16 | 816 | 21 | 1771 | 2 | 4 | 7 | 84 | 12 | 364 | 17 | 969 | 22 | 2024 | 3 | 10 | 8 | 120 | 13 | 455 | 18 | 1140 | 23 | 2300 | 4 | 20 | 9 | 165 | 14 | 560 | 19 | 1330 | 24 | 2600 | 5 | 35 | 10 | 220 | 15 | 680 | 20 | 1540 | 25 | 2925 | -----+------+-----+------+-----+------+-----+------+-----+------+

97. TABLE GIVING THE NUMBER OF BALLS CONTAINED IN A SQUARE PILE, THE BASE OF WHICH IS X, AND IN A RECTANGULAR PILE, THE SIDES OF WHICH ARE X AND X + N.

VALUE | DIFFERENCES | VALUE OF N. OF +-------------+----------------------------------- X. | 2d. | 1st. | 0. | 1. | 2. | 3. | 4. | ------+------+------+------+------+------+------+------+ 2 | 7 | 9 | 5 | 8 | 11 | 14 | 17 | 3 | 9 | 16 | 14 | 20 | 26 | 32 | 38 | 4 | 11 | 25 | 30 | 40 | 50 | 60 | 70 | 5 | 13 | 36 | 53 | 30 | 85 | 100 | 115 | ------+------+------+------+------+------+------+------+ 6 | 15 | 49 | 91 | 112 | 133 | 154 | 175 | 7 | 17 | 64 | 140 | 168 | 196 | 224 | 552 | 8 | 19 | 81 | 204 | 240 | 276 | 312 | 348 | 9 | 21 | 100 | 285 | 330 | 375 | 420 | 465 | 10 | 23 | 121 | 385 | 440 | 495 | 550 | 605 | ------+------+------+------+------+------+------+------+ 11 | 23 | 144 | 506 | 572 | 638 | 704 | 770 | 12 | 27 | 159 | 650 | 728 | 805 | 884 | 962 | 13 | 29 | 196 | 819 | 910 | 1001 | 1092 | 1183 | 14 | 31 | 225 | 1015 | 1120 | 1225 | 1330 | 1435 | 15 | 33 | 255 | 1240 | 1360 | 1480 | 1600 | 1720 | ------+------+------+------+------+------+------+------+ 16 | 35 | 286 | 1496 | 1632 | 1768 | 1904 | 2040 | 17 | 37 | 324 | 1785 | 1988 | 2091 | 2244 | 2397 | 18 | 39 | 361 | 2109 | 2280 | 2451 | 2622 | 2793 | 19 | 41 | 400 | 2470 | 2660 | 2850 | 3040 | 3239 | 20 | 43 | 441 | 2870 | 3080 | 3290 | 3500 | 3710 | ------+------+------+------+------+------+------+------+ 21 | 45 | 484 | 3311 | 3542 | 3773 | 4004 | 4235 | 22 | 47 | 529 | 3795 | 4048 | 4301 | 4554 | 4807 | 23 | 49 | 576 | 4325 | 4600 | 4876 | 5152 | 5428 | 24 | 51 | 625 | 4900 | 5200 | 5500 | 5800 | 6100 | 25 | 53 | 676 | 8525 | 5850 | 6175 | 6500 | 6825 | ------+------+------+------+------+------+------+------+

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Ordnance Instructions for the United States Navy.Chapter I: Ordnance and Ordnance Stores (2)

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