Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/296

GUNMAKING [SMALL ARMS. breech, when the barrels are closed ; or the catch shown in fig. 5 may be adopted. Some makers, instead of using the hinge principle introduced by Lefaucheux, close the breech in other ways ; thus in the Henry action the barrel does not move, but is closed at the breech end by a sliding ver tical block, which is depressed for the admission of the cartridge by a lever underneath the trigger guard ; the striker passes through the block, which on being lowered extracts the cartridge. The power of a modern rifle is limited only by the power of the shooter to withstand the effect of recoil and to use a heavy piece. The momentum of the ballet forwards up to the time of its leaving the muzzle is equal (neglecting the weight and motion of the gas generated by the powder charge) to that of the gun backwards at any instant. Supposing the gun to weigh 150 times as much as the bullet, it will acquire a velocity against the shoulder equal to the 150th part of that acquired by the bullet. Practically it is this velocity which measures the severity of the recoil, and the heavier the gun and the more powerful the shooter the more momentum can he afford to impart to his bullet. This momentum may be composed of high speed and low weight, or of low speed and high weight. A light bullet starting with a high velocity travels fast at first and drops but little at a short range ; it speedily, however, suffers retardation by the resistance of the air, and would soon be beaten by a heavier bullet of the same diameter starting with the sarc.3 momen tum. The Express rifles carry out this principle with great complete ness, employing heavy powder charges and imparting very high spssd to a light bullet, so that a range of about 130 to 150 yards is traversed with a drop not exceeding 1 foot. Fig. 12 shows the nature of bullet generally used for these pieces; the hollow in the centre permits the lead to expand and flatten out on strik ing, inflicting a wound of great severity. Explosive bullets are also employed by some sportsmen. In fig. 13 are Fig. 12. FIG. 13. Rifle cartridges. shown rifle cartridges loaded ready for use. The solid brass-drawn case is now almost universally adopted, both for sporting and military purposes. The Martini-Henry rifles used by the British army, however, still use the soft brass-crimped case. Military Rifles. The principle of rifling small arms seems to have been discovered about the beginning of the 16th century, but does not appear to have been employed for warlike purposes till the middle of the 17th. In 1680 each troop of life-guards was supplied with eight rifled carbines. In 1800 the 95th regiment, now the rifle brigade, was armed with a 20-bore muzzle-loading rifle. The diffi culty of loading a rifle after firing a few rounds was the great obstacle to its use in the field. Several methods were devised of providing anvils at the bottom of the bore on which a loose ball dropped in could be hammered to fit the grooves, but the principle of expansion by the action of the powder was not brought forward till 1836, when Mr Greener submitted an egg-shaped bullet, having an opening at one end to receive a conical plug, which when driven home by the gas expanded the bullet into the grooves. Shortly after this the French chasseurs were armed with a rifle throwing an elongated bullet with a hollow-coned base. This was improved by Captain Minid, who added an iron cup to fit into the cone and expand it when forced home by the gas. For this cup a wooden plug was substituted in the three- grooved Enfield rifle in 1855. About this time Sir J. Whitworth brought forward his hexagonal rifling, the guiding idea of which was that every part of the hexagon except the actual corner should do its share of the work of giving rotation. He proposed for a barrel 39 inches long a bore of 45 inch, having one turn in 20 inches. This was intended to be suitable either for an expanding bullet, or for one possessing an easy mechanical fit. The length of the bullet was increased, and the form thus modified suffered much less from the resistance of the air than the previous patterns. The question of breech-loading for military weapons now began to assume importance. About 1841 the Prussians had adopted the needle gun, a breech-loader on the bolt principle. It was a rough weapon compared with the pieces lately introduced, but a great advance on any known at the time. A conical bullet rested on a thick wad, behind which was packed the powder, the whole being enclosed in strong lubricated paper. The detonator was in the centre of the hinder surface of the wad, so that to ex plode it a needle had to be driven forward from the breech through the base of the cartridge and through the powder. This was accomplished by the action of a spiral spring, when set free by the pulling of the trigger. This arrangement possessed many defects : the gas escaped freely at the breech ; the long needles rusted and broke ; the springs failed ; and the weight of the piece was excessive. Such failings caused the sterling merit of the principle to be underrated, and it was not till 1864 that a committee of officers recommended the introduction of breech-loading arms for general adoption in the British army. The triumph of Prussia in the Seven Weeks War with Austria in 1866 at once drew attention to the urgency of the case, and caused all civilized powers to re-arm their troops. In England the Enfield rifles (three-grooved expanding bullet muzzle-loaders) were converted into breech-loaders Ly the adoption of the Snider method, which consisted in cutting away 2 inches of the upper part of the breech end of the barrel so as to admit the cartridge, which was pushed forward into a chamber formed by enlarging the end of the bore. A block, opening on a hinge, was then shut down to fill up the space behind, forming a false breech against which the base of the cartridge abutted. The striker consisted of a needle passing through this breech block; when struck from behind by the hammer it was driven against a cap in the base of the cartridge, exploding the charge. By this means the existing rifles were rapidly converted, and the army was provided with a breech-loader of satisfactory efficiency should any emergency arise. Proposals were then invited, and a number of inventions submitted, the result of which was that in 1869 the combination of the Martini breech action with the Henry barrel was decided on for future manu facture, and the whole of the British army is now provided with these weapons (see figs. 14, 15, 16, 17). The general principles of manufacture are the same for all kinds of military breech-loading rifles. It will be sufficient to give the details of one in extenso. The manufacture of the Martini-Henry rifle, as carried out at the Government factory near Enfield, involves 2004 separate operations which have to be performed on each rifle before it is complete for issue. This number is subject

to slight variations caused by changes of pattern from time