So at some date not long after that at which straight grooving was put into common practice, the evolution of the rifle made a further advance by the introduction of spiral grooving. This gave all the advantages of the straight grooving, and in addition, spin in a definite plane to a definite degree; so that it entirely superseded straight grooving in all countries where fire-arms were in common use. Experience amply confirmed the superiority of the twisted rifling. With the accession of accuracy the skill of the marksman naturally increased, enthusiasm grew, and the shooting competitions gained in popularity and importance. “Le goût de tir des armes rayées de précision est poussé jusqu’à la passion: passion qui excite l’amour-propre en ne laissant pas à la maladresse l’excuse si facile de l’imperfection inévitable de l’arme à canon lisse.”[116]
BULLET MOULD
Yet in spite of improvements the rifled musket remained unrecognized as a military weapon for another two hundred years. Its use was confined to sporting purposes; though far less in common use than the smooth-bore it became, for its increased accuracy, the favourite weapon of the deer-stalker and the chamois hunter. In England it was little known before the nineteenth century; and when, in 1746, Robins made his famous prophecy, the possibilities inherent in rifled fire-arms, even such as were then in existence, were unrealized by the people of this country.
It is to be noted that it was only in increased accuracy of flight that the rifled gun had a superiority over the smooth-bore; no increase in ranging power was possessed by it. And yet this claim is constantly made by old writers, that, probably (as they say) owing to the fact that increased resistance of the ball to initial motion gave time for all the charge to be thoroughly ignited, the rifled gun carried further than the smooth-bore. As a fact, the contrary was true; other things being equal, the range of the rifle was actually less than that of the smooth-bore. The explanation of the paradox was given by Robins. “It is not surprising,” he said, “that those habituated to the use of rifled pieces gave way to prepossessions like these; for they found that with them they could fire at a mark with tolerable success, though it were placed at three or four times the distance to which the ordinary pieces were supposed to reach: and therefore as they were ignorant of the true cause of this variation ... it was not unnatural for them to imagine, that the superiority in the effect of rifled pieces was owing either to a more violent impulse at first, or to a more easy passage through the air.” The true value of the spiral grooving resided, of course, in the spinning motion which it gave the ball. By making this spin uniform two variable factors determining the trajectory were thereby transformed into constants: first, the effect just mentioned, the influence of the varying resistance of the air on the parts of the ball which met it at different speeds, some parts moving forward relatively to its centre and some parts retreating; secondly, the effect of eccentricity of mass and irregularity of exterior surface, which were both almost nullified by the rotation. The importance of this second effect may not at first sight be apparent. It must be remembered, however, that the balls used in those days were of the roughest description; cast in hand moulds, “drawn” in cooling to such an extent that in a large proportion an actual cavity was left in their interior, which could be revealed only by cutting them open; their burrs removed with pincers, their surface rough and broken, their shape distorted by the ramrod’s blows.
The superiority of the rifle in accuracy was generally admitted; and this advantage not only counterbalanced such deficiency in ranging power as may have accrued from the use of grooving, but actually led to a general but mistaken belief that the rifle carried farther than the smooth-bore. The reverse was the case. Moreover, it was not safe to use with a rifle the very large charges of powder which could be used with safety with a smooth-bore musket. On account of the resistance to motion of the ball which had been forced by ramrod, sometimes even by mallet, down the grooved barrel of the rifle, high chamber pressures resulted, and not infrequently the barrels burst. Hence in spite of the thicker metal of which they were generally made, rifles could only be used with moderate charges, and so could not compete on equal terms, in this respect, with the smooth-bores for superiority of range.
Toward the end of the eighteenth century events occurred which drew attention to the utility of the rifle for military purposes. In spite of its slow rate of fire—to load it carefully took from one and a half to two minutes—it showed itself to be a very effective weapon in the hands of French tirailleurs, Swiss, Austrian, and Tyrolese Jägers, Hottentots and American Indians. In the War of Independence the superior accuracy of their rifles, and their capacity for hitting at ranges beyond the 200 yards which were about the limit of the smooth-bore musket, placed the American backwoodsmen at such an advantage over the British troops that riflemen were recruited on the Continent and sent across the Atlantic to counter them. New military tactics came into vogue at this time, their inception influenced by the gradual improvement in fire-arms and artillery. Bodies of riflemen, “a light erratic force concealing itself with facility and forming an ambuscade at will,” were formed in the continental armies to act in concert with the masses of infantry as skirmishers or sharp-shooters, their object being to surprise and demoralize the enemy by the accuracy of their long-range shooting. Rifles were now looked on, too, as the natural counterpart of the now flying or horse artillery, “which, from the rapidity of its motions, the execution of cannon-shot in all situations, appears to be the effects of little less than magic.”[117]
RIFLEMAN PRESENTING
(From Ezekiel Baker’s Rifled Guns, A.D. 1813.)