[LECTURE X]. RIFLED SMALL ARMS AND ORDNANCE. Principle of rifling explained by Robins. 1. THE term "rifle" is generally applied to a small arm; any musket or carbine, the barrel of which is provided with grooves for the purpose of giving the rotatory motion, or "rifle action," as before explained, being called a rifle. When this rifling is applied to ordnance, they are called, " rifled ordnance" or cannon. As the first experiments and improvements in rifling were made with small arms, which have now attained to such great perfection in accuracy, combined with long range, it is advisable, before considering rifled ordnance, to give a short account of the different alterations and improvements successively adopted in the "rifle." The Rifle. 2. The early form of fire-arms were breech-loaders; some which loaded at the muzzle having been introduced, it was found that the more tightly the ball fitted the bore, the greater was the accuracy of fire obtained; on account, however, of the bore soon becoming foul, the balls required considerable force to drive them down the barrel, which was accomplished by means of a mallet and iron ramrod. It is generally asserted that the grooved barrel was invented by Gaspard Zollner of Vienna, in 1498; the grooves were parallel to the axis of the bore, and intended to receive the foulness from the discharge of the piece, and thus render the loading easier. It was most probably discovered accidentally, that by twisting these grooves round the inner surface of the barrel in a spiral direction, much greater accuracy of shooting was obtained. 3. The cause of increased accuracy by this arrangement of the grooves, was not however understood, until the science of gunnery was thoroughly investigated by Benjamin Robins, who was the first to recognize the great effect produced upon the trajectory of a projectile from the resistance of the atmosphere. A tract was written by Robins, in 1747, on rifled arms, in which he explained the true value of the grooves, and also stated that greater accuracy would most probably be derived from the use of an elongated projectile (egg shaped). At the conclusion of the Tract are the following remarks:-"I shall therefore close this paper with predicting, that whatever State shall thoroughly comprehend the nature and advantages of rifled barrel pieces, and, having facilitated and completed their construction, shall introduce into their armies their general use with a dexterity in the management of them; they will by this means acquire a Baker's rifle. Rifled-bore with chamber. Carabine à tige. superiority, which will almost equal anything that has been done at any time by the particular excellence of any one kind of arms; and will perhaps fall but little short of the wonderful effects, which histories relate to have been formerly produced by the first inventors of fire-arms." The principles demonstrated by Robins, and his suggestions as to the general application of the rifle principle and form of projectile, were not at the time followed out, and it is only within the last few years that attention has been again directed to the subject. 4. The first rifle introduced into the British army, generally called Baker's rifle, had seven grooves with a quarter-turn, and was fired with a spherical bullet. 5. In 1827, M. Delvigne, a French officer, proposed a plan, for facilitating the loading of the rifle. The charge of powder is placed in a small chamber at the bottom of the bore, and the ball (spherical) which is made to fit loosely in the barrel, rests upon the shoulder of the chamber (Fig. 1, Plate 31), and is expanded so as to fill the grooves by a smart blow from a heavy ramrod. This arrangement, which was tried by the 2nd Regiment of the Garde Royale, in Africa, in 1830, was not found to succeed well on service; the edge of the chamber did not afford sufficient support for the bullet, a portion of the powder lodged sometimes on this edge, causing the grooves to foul, and consequently, not to act efficiently on the ball; and lastly, the ball if rammed too hard was disfigured, which greatly affected the accuracy at 220 yds. (See Rifle Musket, by Captain Jervis). In 1836, the Brunswick rifle was adopted into our service. It had two grooves with a rapid pitch; the projectile was a belted ball, the object of the belt being to prevent the rifle "stripping," owing to the rapid pitch. With regard to this rifle, Lieut.-Col. Dixon, R.A., in a Lecture delivered at the United Service Institution, remarks, "This was an advance in the right direction, and a positive rotation was thus obtained with certainty. The arm was much improved in shooting, although the loading was not so easy as was required, and a great disadvantage existed in the bullet and cartridge containing the powder, being separate in the soldier's pouch." 6. In 1842, Col. Thouvenin (a French officer) invented the "carabine à tige." The "tige" or stem, is made of steel (tempered), and screwed into the centre of the bottom of the bore of the rifle (Fig. 2, Plate 31), round which the charge is placed; the ball enters freely, rests upon the top of the " tige," and is expanded into the grooves by a few blows from the ramrod. But here another defect appeared. The pillar occu pying a large portion of the centre of the barrel, and the charge being placed in the annular space which surrounds it, the main force of the powder, instead of taking effect in the axis of the piece, and on the centre of the projectile, acted only on the spherical portion of the bullet which lies over this annular chamber; and thus, the ball receiving obliquely the impulse of the charge, was propelled with diminished force. Introduction of 7. A most important improvement was now proposed (as before stated in Art. 16, Lecture VIII.) by M. Delvigne, viz. the introduction of an elongated bullet. Such excellent results were obtained in practice with this bullet, that it was introduced together with the carabine à tige into the French army of Africa, in 1846; the bullet had a groove round the cylindrical part (aa, Fig. 2, Plate 31), by which the cartridge was attached to it, and its point was held in the axis of the barrel by the form of the head of the ramrod. elongated balls. Prussian needle gun. Minié bullet. 8. The Prussians adopted a breech-loading rifle with four grooves, usually termed the needle-gun, the projectile for it being of a cylindro-conical form. The chamber into which the bullet is placed is slightly conical for the convenience of loading, and the diameter of the projectile at the shoulder is equal to that of the bore through two opposite grooves; the bullet when fired will therefore be compressed by the projecting lands,1 and the necessary rotatory motion thus given to it. The projectile has a wooden bottom, in the lower end of which is a small cap filled with detonating composition; in order to ignite this there is a small steel wire 03 in. in diameter at the bottom of the bore and in the axis, which by the action of the trigger is suddenly forced through the charge of powder, and the blunt end striking against the detonating composition in the wooden bottom of the bullet causes it to explode, and thus fire the charge. The mechanism of this rifle is complicated, and could not be thoroughly understood without the aid of very careful drawings. 9. As, however, the carbine à tige was inconvenient to clean, the chamber round the tige soon becoming foul, the pillar liable to be broken, and the ramming down of the bullet very fatiguing to the soldier, M. Minie proposed to remedy these disadvantages in the following manner :-The stem was removed from the bore of the rifle, and the bullet made to expand merely by the gas from the explosion of the charge, acting on an iron cup (Fig. 3, Plate 31) placed in a conical hollow, and driving it up into the narrow end of the hollow, thus causing the surface of the cylin drical part to expand into the grooves. A rifle on the minié principle was brought into the service in 1851, but in 1852, a 1 Lands are the spaces between the grooves. Pritchett bullet. Service bullet and plug. Principle of expansion. Committee was appointed by Lord Hardinge, for the purpose of investigating the question of rifled arms, and the principal gunmakers were invited to submit pattern rifles. 10. The bullet finally adopted by this Committee was the Enfield Pritchett, of 1853 (Fig. 4, Plate 31), and is described by Captain Jervis, R.A.,1 as follows: "The expansion of this bullet is obtained by its being made of such a length in proportion to its diameter, that the force of the powder when ignited, acting suddenly against the base, drives it up slightly before the inertia of the point of the bullet is overcome, thus causing it to expand throughout its cylindrical part, and more especially at the shoulder, the most important part being directly over the centre of gravity. The hollow at the base is used more with the view of lightening the bullet, and throwing its centre of gravity forward than to obtain expansion by its means." With this bullet, however, the barrel was found to foul, and a plug made of box-wood was proposed by Colonel Hay, Commandant of the School of Musketry, at Hythe, and adopted into the service. With regard to this plug, Colonel Dixon remarks,-"The expansion into the grooves, so ensuring the necessary rotation, is effected at the instant of the inflammation of the charge of powder, in consequence of the upsetting of the lead, assisted possibly by the wood plug which closes the orifice at the base of the bullet, but which no doubt prevents any collapsing of the sides of the bullet when leaving the barrel, a circumstance which would otherwise happen, and thus disfigure the shape, and act prejudicially in other respects. The advantages on the side of the plug are, besides the above, the less frequent fouling of the barrel; in fact, the grooves are cleaned out and lubricated after every shot (Fig. 5, Plate 31). 11. The idea of the expansion of the bullet by the action of the charge upon its base was originated by M. Delvigne previous to the introduction of the Minié system, for in a pamphlet, "Sur le fusil rayé à balle allongeé," M. Delvigne states as one of the principles of his invention. "To cause the projectile to expand, either by the force of the ramrod, or by the action of the powder in a hollow in the posterior part of the projectile." 12. Mr Greener, of Birmingham, in a work entitled, "Gunnery in 1858," claims the invention of the expansion. system by means of a plug, and also asserts a most important principle, "that the centre of gravity should be in the head of the projectile." 1 The rifle musket. Whitworth's, other bullets. 13. A great many elongated bullets have been proposed by different inventors, viz. Whitworth, Lancaster, Wilkinson, Jacob, &c. (Figs. 6, 7, 8, and 9, Plate 31). The principle of rifling adopted by Whitworth and Lancaster will be noticed in the remarks on rifled ordnance. Very excellent results have been obtained with the rifles of both these inventors.1 The corps of Sappers are armed with the Lancaster carbine; the chief advantages of this arm are, that considerable range with great accuracy is obtained in practice from it, and as there are no grooves in the barrel, it is not liable to foul, and can be readily cleaned; when tried at Hythe, the Lancaster bullet was found to "strip" very frequently, but this defect has been in a great measure obviated. 14. Wilkinson's bullet (Fig. 7, Plate 31), differs from other expansive bullets before described, in being solid, having no hollow at the base, but having two deep annular grooves in the cylindrical part. The principle of its expansion is thus described in a pamphlet written by himself." Since the projectile has no hollow in the base, the action of the powder upon it, must be different from the minié system, inasmuch as it must drive the ring-formed cylindrical part into and upon the conical fore-end, and so accomplish the filling of the grooves; but this is only possible, providing the conical part of the projectile has the necessary weight." This bullet has been adopted into the Austrian Service, the Swiss having used a projectile on a similar principle for some time. It possesses the great advantage of simplicity of construction. 15. Col. Jacob, of the Bombay Artillery, has given a description of his projectile in a pamphlet. He obtained with it a very long range, but a large charge is required, the inclination of the grooves is very great, and as will appear by Fig. 6, Plate 31, immense friction is caused by the change in form of the bullet within the barrel. 16. The following Table will shew the relative dimensions, &c. of the small arms successively adopted during the last few years for general use in the British Service. 1 The Whitworth projectile has a very low trajectory, a point of the greatest practical importance. 2 The bullet of 568 in. was reduced by order, dated Feb. 19, 1859 to 55 in. |