The various black powders, every' variety having its merits peculiar to itself, have served us long- and well; but, with the appearance of the multiple loading rifle, smokeless powder is coming into extensive use for military and hunting purposes. The advantage of smokeless rifle powder is, that the prod ucts of combustion being entirely. or mainly. gaseous, the solid or unconsumed residue is very small, leaving the bore of the rifle comparatively clean after firing. The smoke produced is almost nothing-, g,enerally, only a slight puff being noticeable and that dissipating- immediately. The chief advantag,e from the sportsman's or hunter's standpoint is the high chamber pressur of from fifteen to twenty-five tons per square inch, giving to the bullet very high muz zle velocities--2,ocio 2,5oo feet per second, vi hieli consequently g,ive very flat trajectories. .1 Hat trajectory lias always been insisted on hy sportsmen for hunting rifles. even that resulting from heavy charged military arms not sat isfying them, and rightly so, for it almost eliminates or at least greatly simpli fies the calculations of distances, and the constant manipulation of sights common to the black powder high trajectory rifles.
Compared with chamber pressures developed by black powder the differ ence is remarkable, as with black powder the pressures were probably never over fifteen tons per square inch, whereas with smokeless powder, using a charge to impart 2,000 feet velocity, the chamber pressure runs up to twenty or twenty-five tons per square inch, and to g,ive 2,5oo feet velocity pressures run up from twenty-five to thirty tons for regular charges and for excessive charges sometimes as high as forty tons per square inch.
Such enormous pressures require greatly increased strength and solidity in the breech mechanism, and a corresponding increase in the strength of the barrel. Both barrels and action are now made of a superior grade of steel, costing five times as much as the machinery steel used for black powder rifles, and the barrels are increased in thickness over the chamber and to keep down the weight reduced L, thickness toward the muzzle. The jacketed bullet be ing so much harder than lead would wear out the rifling rapidly' were not the barrels made of hard material, as hard as can be properly worked. All of which add greatly to the cost of the present rifle.
The chamber pressures in nitro charged shot-guns do not compare 'with the intensity of pressures in rifles, they averaging generally not over five or six tons per inch. Nitro powders as used in shot-guns should never be used
in rifles; nothing but smokeless rifle powder should be used, following care fully the directions for loading, and no experimenting with excessive charges should be indulged in.
The high chamber pressure giving great velocity to the bullet, necessi tates, in order to secure steadiness of flight, a more rapid twist to the rifling-, say one turn to six and a half to twelve inches, instead of the sixteen to twenty-four in the rifles made for black powder. Leaden bullets fired with high velocities through such barrels will not follow the rifling, but will strip and override the lands, for which reason the surface of the projectile is made of some harder metal, but to retain the high specific gravity of the lead with the consequent ability of the ball to better overcome the resistance of the air, the greater portion of the bullet is made of a lead slmr, and then coated or jacketed with a covering, about 0.02 inch thick, of some hard metal, as steel, copper, nickel, or German silver.
The soft lead bullet of the old rifle is made of about the same or even less diameter of the bore, and then under the effect of its inertia and the blow produced by the combustion of the charge was set out into the grooves of the rifling. With the jacketed bullet the maximum diameter exceeds that of the bore by a difference nearly equal to double the depth of the grooves and the bullet is forced through rather than set out into them.
The largest game in the world, the royal Bengal tiger of India, the ele phant and the rhinocerous of Central Africa, arc now being successfully hunt ed and slain by men using the .303 caliber Savage rifle. Sportsmen who have never tried the small-caliber rifles and smokeless powder ammunition are somewhat skeptical as regards the killing or stopping power of the small metal-covered expanding bullets. The secret of the deadly effect of these small projectiles lies in their expanding qualities and extraordinary velocity, which impart a percentage of their energy to the otherwise inert flesh and bone; and these substances being acted upon by so quick a blow, become themselves pro jectiles, following a well-known mechanical law, lacerating the surrounding tissues and bone, and leaving a path of destruction which is widened by re sistance encountered by the bullet.