Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/298

Rh 284 There are two outer circles extending to the eye, and approximately resembling the sketch in shading. If the barrel is untrue in interior surface, or bent, the cone will at once lose its regularity, and the sides AB, AC will no longer be straight. Should they be irregular, the barrel is &quot;set&quot; by striking with a hammer or ebonite mallet across a set ting block. The barrel is next placed in a machine, and a horizontal spindle is run through it ; on this spindle are two close- fitting gauges, one in the centre and one at the end ; the barrel is then caused to revolve on the spindle, and an indicator with a long arm recording small graduations is inserted at the free end between the spindle and the barrel ; any irregularity of turning is multiplied 200 times by the long arm, and becomes at once apparent. After passing these tests the barrel is finish-turned ; the back sight is soldered on and screwed, and the fore sight is brazed on; the size of bore is then gauged, after which the process of polishing is completed and the barrel is ready for rifling. Rifling. The rifling consists of seven grooves of the form shown in fig. 1 7. The twist is such that the bullet makes one complete revolution while travelling 22 inches ; that is, one turn in 49 calibres of 45 in., to employ the phraseology generally applied to the rifling of cannon. Each groove is cut separately by a tool which acts when pulled ; it forms the groove by five successive -cuts, being forced to project a little more at each cut; it thus passes thirty-five times up and down the barrel to complete the rifling, which can be done in half an hour The size of bore is now finally tested; it must lie between 449 and 451 inch. The rifling is similarly tested, and the twist gauged. Cartridge The breech end of the barrel is next chambered out to chamber receive the cartridge, which is of the kind known as &quot; bottle- shaped.&quot; The exterior of the breech end is of &quot;Nock s&quot; form, the upper surface being a flat, true to the bore. This flat guides all the fittings ; the barrel is placed in a machine true to the flat, and the sights are gauged for line and elevation. No allowance is made for the deflexion due to twist of rifling, it being very slight. The barrel is lastly screwed at the breech end to fit the body. Each barrel is twice subjected to proof by powder, once before rifling, once after. Sixteen are placed in a cast-iron frame ; a temporary steel screw, furnished with a vent, closes each breech end, which rests against a leaden bar. The barrels are loaded from the muzzle ; a train of powder ignited by a cap fires them simultaneously ; the bullets are caught in a hollow cast-iron receiving frame, shaped like the shell of a snail. The charge for the first proof is 7J drs. ( = 205 grs.) of powder and a bullet weighing 715 grs., secured by a half-inch cork wad forced down over it. The second proof is the same, except that only 5 drs. ( = 137 grs.) of powder are used. The service charge is 85 grs. of powder with a bullet of 480 grs. The barrel when finished is browned by being coated with browning mixture, and caused to rust in a steam tank ; it is then brushed with wire brushes. This process is repeated four times, after which the exterior is oiled over. The browning mixture consists of Proving Spirits of wine 5 oz. Spirits of nitre 8 ,, Tincture of steel 8 ,, Nitric acid. ., . . 4 , , Corrosive sublimate 4 oz. Blue vitriol 4 ,, Water 1 gal. Stock. The stock is in two parts, the butt and the fore-end. They are of Italian walnut wood, and are supplied roughly shaped. They are tested for straightness of grain ; weight, as indicating strength; &quot; shakes&quot; or cracks ; &quot;galls,&quot; caused by injuries over which the wood has grown ; saltness (which would cause absorption of moisture and consequent rusting), bv putting a shaving into a solution of nitrate of silver ; [SMALL ARMS. and also for appearance. Those accepted are thoroughly seasoned by keeping, or dried in a desiccating chamber, warmed by hot air ; they then go to the shaping machines, where they are cut to size by revolving cutters, making 4000 revolutions per minute, and are afterwards turned in copying lathes, hollowed out by copying gouges, and bored to take the fittings. They are then tested, machined, hand- finished, and oiled up. The body is of mild steel ; it is stamped out from the BO bar ; it is then drifted through by a slightly tapered bar carrying a succession of cutters on it. The front part of the body is then screwed to suit the screw on the barrel, so that when home it shall fit accurately to the breech end. The lever, and indeed all parts except screws and springs, are stamped out of solid bar. Each part is milled by machinery to a correct fit ; every fitting is interchangeable, and nothing is marked for selection to fit anything else. Each part is browned in the same way as the barrels, or blued. On completion all parts are taken to the assembling room, where they are fitted together, screwed up, and turned out as finished rifles ; after which they are taken to the practice ground, and tested for accuracy and extraction of cartridge by being fired from a rest at a target, the range being 500 yards. The bayonet consists of a steel blade welded to a Ba wrought-iron socket. Steel of a superior quality being used, it is supplied in bars, is cut into lengths, and is welded by the aid of borax to a short rod of rolled iron. The two arc so put together as to form a right angle ; the steel bar is put into a &quot; Rydering &quot; machine, which gives it a great number of rapid blows, and shapes it roughly into a blade. It is then rolled and cooled gradually under charcoal and coal-dust for annealing purposes. The socket is then drilled, and the blade ground. They are then bent into position and become a bayonet. Turning and finish-boring complete the sockets, while the blades are fine-ground, hardened, tempered, tested, and polished. The sockets are then browned and adjusted to the rifles. About 1400 operatives are employed at the Government factory ; each Martini-Henry rifle costs about 48s., all expenses reckoned; and to render the establishment thoroughly remunerative, the out-turn should be about a rifle a week per man. The systems of breech-loading muskets employed by Ya different nations are shown in the following table : of kel Country. Nature. &quot;o | X Action. Austria &quot;Werndl .. r &amp;gt; Block rotatinf sideways. Bavaria Werder 4 Falling block. Denmark England France. . . Remington Martini-Henry Gras 5 4 4 Block hinged to rear, sup ported by a cam. Falling block. Slidinf bolt. Germany Mauser 4 Do. Italy Vetterli 4 Do. (magazine gun). Russia Berdan 5 Block hinged to front (old). Spain Remington 5 Sliding bolt (new). Block hinged to rear, sup Sweden .. Do ported by a cam. Do. Switzerland Vetterli 4 Slidingbolt(magazinegun). Turkev Martini-Henry 4 Falling block. United States Springfield 5 Block hinged to front. It will be noticed that the Vetterli gun, used by the Italians and Swiss, is a repeater or magazine gun. It contains a supply of eleven cartridges, arranged in a tube running under the barrel, and forced by a spring into the loading position one by one, as the previously fired empty one is extracted. The arm can thus fire twelve rounds with great rapidity without reloading ; it can also be used as an