Page:Once a Week Jul - Dec 1859.pdf/20

2, 1859.] other bands, damage by bending the barrel, and so on; the probably true reason is overlooked. Iron is acted on by acids; those acids are furnished to the interior of the barrel by the combustion of sulphur and nitre, which should be wiped away as produced. The wearied soldier neglects this, and throws himself down to sleep on the ground by the side of his fouled gun, after a hard-fought day, and on the following morning the interior of the barrel has a rusted roughened surface, like that of a file. The leaden bullet, expanded by the discharge, gradually communicates a skin to the barrel, just as every workman knows that a file will get clogged in cutting lead. This skin gradually thickens, and the balls will no longer pass down. So long as iron shall be liable to rust, this difficulty can only be surmounted by furnishing the soldier with a ready means of keeping a continual polish on the inside of his barrel, equivalent to its original polish.

The principles which should govern the construction of a gun to discharge projectiles so as to obtain the maximum of range and accuracy with a given propelling power, hold good alike both in machine guns and hand guns. The best properties of the hand gun are the best also for the wheel guns. By the discharge of powder force operates in three ways: to make the gun recoil; to expand the barrel laterally, with a tendency to rend it open; and to propel the projectile. The proportion of force expended on the projectile, depends on the disproportion between the weight of the gun and that of the projectile. If they were of equal weight, they would be driven with equal force in opposite directions, and to obtain the maximum effect the gun should be absolutely unmoved by the discharge; therefore a light gun is merely a contrivance to produce a small effect. With a light fowling barrel we help weight first by a wooden stock, and next by the body of the shooter; and if the contact be not close, we learn what a “kicking” gun means.

The proportions of weight being settled, the next question is of the proportion of length of bore to diameter, and this again depends on the charge and quality of the powder used. If the bore be too short, the powder will not have room to be thoroughly burnt and perfectly expanded, and power will be wasted in that mode. If too long, power will be wasted in surplus friction between ball and barrel. And again the powder may be too quick or too slow in exploding. If too quick, it will need a heavier and stronger gun, and for this reason gun-cotton, the most explosive of all, is not used in guns, though experiments have been made to make it bum slower by mixing with saw-dust. The want of length of bore in guns is illustrated by short carronades, in which the flame is forced backwards, charring a ship’s sides at the instant the shot leaves the muzzle. The want of weight in a gun is illustrated by the fact, that if a recoiling gun be backed against a solid bank of timber, it will throw the shot further—but there will also be some risk of bursting.

Apart from the question of weight, there is the consideration of thickness of metal to resist lateral expansion, and even in wrought metal it will be found—apart from the question of transport—that the thickness of metal should be equal to the diameter of the bore. Swiss rifles and American rifles are the heaviest known guns in this respect, and the American are considerably the largest. Making allowance for prejudice, it is impossible to doubt that good practical reasons exist where a hunter prefers to carry about a very heavy gun. A common proportion is a 36-inch barrel with a bore of ⅜-inch, equal to 96 diameters, and the accuracy is remarkable; but the shooting range rarely exceeds 100 yards, a distance that modern practice holds in contempt. Yet it is doubtful if an Enfield rifle will cut off a squirrel’s head on a tree-top at 100 yards without damaging the skin. Neither can it be laid in the hollow of the hand at rest, and discharged without moving the barrel by recoil, as can be done by a heavy American rifle.

“Brown Bess” was nominally a “smooth bore”—nominally only—and the results gained from rifles have thrown contempt on all smooth bores. But a great part of the result is gained by the fact that in the rifle there is no windage and no loss of power by the gases escaping between the ball and the barrel. “Brown Bess,” on the contrary, was all windage; for the paper wadding helped little. In the rifle, however, there is a loss by friction. All our English rifle practice, old and new, is to make the ball do its own packing by a tight fit. An old-fashioned rifle had the ball hammered in by a wooden mallet and then driven down by an iron rammer, leaving the form that of a short cylinder, with one flat and one hemispherical end, and jagged portions of a screw round it. As the flat end was foremost, the wonder is how any accuracy at all was attained even at 150 yards. The Americans envelope the ball in a piece of greased skin, and it leaves the barrel as a true sphere, though with a spinning motion, correcting any aberration with which it leaves the barrel. Yet this spinning motion does not wholly remedy the defect of the barrel, for any bruises at the mouth induce inaccuracy; and so sensible are the hunters of this, that in shooting-matches they use a rifle with a supplementary mouth-piece to prevent injury.

We have taken to the rifle, in the full faith that it can cure all disorders of inaccuracy. But we have taken up a complicated tool, involving many troubles in its use and even disadvantages. The spinning movement involves increase of friction and some consequent waste of power. If two barrels be made exactly alike in all other respects, and one be rifled and the other smooth bored, and both loaded exactly alike, it will be proved that the smooth bored will have considerably the longer range, though the accuracy of flight be less. But again, the damage done by the rifle ball is far greater than that by the smooth bore. The spinning movement when suddenly diverted by the object aimed at, enlarges its circle and makes a gaping hole, emphatically “a ragged bullet,” three times the size of the smooth bore. And with a great gun a very damaging effect is produced on stone walls by this process.

We fail to produce the best effect in the construction of hand guns, because we aim at two things wholly incompatible. The quality of this gun is sacrificed as a projector by the attempt to convert it into a pike. We have, it is true, won battles with Brown Bess, but that has been mainly