46. What are ring or grommet wads, and their use?
They consist of a ring of rope yarn, about 0.7 in. thick, with two pieces of strong twine tied across at right angles to each other. The size of the ring is the full diameter of the bore, in order that it may fit tight, and stop the windage. They increase the accuracy of fire, and are to be preferred when the object of the wad is to retain the ball in its place, as in firing at a depression. They stop the windage best when placed behind the ball. They may be attached to the straps, or to the ball by twine, or may be inserted like other wads after the ball.
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47. How are junk-wads made; and for what are they used?
Wad-moulds for each calibre,—consisting of two cast-iron cylinders of different diameters set in oak, or of two strong pieces of oak, strapped with iron, and joined by a hinge,—are employed in their manufacture. The junk, after having been picked, is compressed by being beaten in the smaller mould with a maul and cylindrical drift—the latter nearly of the size of the mould—until it assumes the requisite dimensions; it is then taken out by raising the upper part of the mould, and closely wrapped with rope yarn, passed over it in the direction of the axis of the cylinder, and fastened by a few turns around the middle of the wad. It is then placed in the large mould, and again beaten with the maul and drift, until its diameter is increased to that of the mould, when it is taken out and its diameter verified by a wooden gauge corresponding to the large shot-gauge of the calibre. These wads are used for proving cannon.
48. Describe the process of loading field shells.
They are set up on their sabots, the charges measured out in the proper powder measure, and poured in through a copper funnel. The fuze-plugs are then driven in with a mallet, allowing the tops to project about 0.1 in., care being taken not to split them. The holes in the plugs are then carefully reamed out, and stopped with tow-wads, which are pressed in firmly with a round stick.
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49. Describe the process of loading spherical case shot.
The shot having been cleaned, the balls are put in. A stick with a less diameter than the fuze-hole, and having a groove on each side of it, is inserted and pushed to the bottom of the chamber by working the balls aside. The shot is then placed in a sand-bath or oven, and brought to a proper temperature to receive the sulphur, which in a melted state is poured in to fill up the interstices between the balls; the shot is allowed to cool, and the sulphur to harden, when the stick is withdrawn, and the sulphur adhering to the sides of the eye and the surface of the shot is removed. If a fuze-plug and paper-fuze are to be used, the charge is poured in and the plug inserted exactly as in case of a shell; but, if the Bormann fuze is to be used the charge is inserted and the stopper and fuze screwed into their places, care being taken before placing the fuze in position to puncture the covering of the magazine, so that the fire can communicate with the charge.