Page:EB1911 - Volume 23.djvu/348

 “30th year” (1900) and “38th year” (1907) rifles are bolt-action weapons, with no special peculiarities. The Swiss rifle (Schmidt-Rubin) is a remarkable weapon of the straight-pull type, short, and possessing a. relatively low velocity. EB1911 - Rifle - Fig. 17 Krag-Jorgensen.png . 17.—Krag-Jörgensen.

EB1911 - Rifle - Fig. 18 U.S. Short Rifle.png . 18.—U.S. Short Rifle. (Text Book of Small Arms, by permission.)

The Use of the Rifle in War.—The study of “musketry” as distinct from target shooting may be said to date from the Franco-German War. Previously military students and practical soldiers concerned themselves rather with the tactical question of fire-power—fire versus shock, bullet versus bayonet and so on—than with the technical question of its application. This was natural enough in the days of short-range fighting. But when bullets began to cause losses at 1000 yds. and more from the firing point, formations that presented the least vulnerable target had to be discovered and tested, aiming grew more difficult as the range increased, and firing by word of command in large units became practically impossible. The very accuracy and range of modern weapons involved new problems. The necessity, in the larger area of effective fire, of setting the sights to the distance of the mark made further demands on fire-discipline and brought up the difficult problem of judging distance. The possibilities of varying the rate of fire conferred by the magazine rifle also demanded close study. Each war, as it came, produced fresh evidence as to what was possible and what was not in matters of, fire-control, the best rate of fire for effect, the range at which fire should be opened, and other half-tactical, half technical problems. Thus, although many points still remain in the region of controversy, certain ideas and principles are almost universally accepted as the basis of service musketry.

The leading idea is that of the “cone of dispersion.” A modern rifle, even fired from a fixed rest under good conditions, will not place shot after shot in the same spot, but the shot marks on the target form a more or less close “group.” When to this error of the rifle and the ammunition there is added the personal error of the marksman, the group is larger, and in the collective fire of a squad it is larger still. Now the trajectories of bullets that do not strike in the same place naturally do not coincide, and the group on the target is represented in the air by a cone or sheaf of trajectories. The bullets of this sheaf striking the ground on either side of the target form on the ground a much elongated ellipse. The ellipse containing 90% of the bullets fired is called the beaten zone. It is usual, however, to calculate from the “effective” zone, or that which contains 75% of bullets. Within the “effective” zone, and at its centre, is found the closely grouped “nucleus” of

50% of bullets. With the British ·303 rifle in collective fire, the depths of these zones are:— The target aimed at and sighted for is at the centre of the zone (see fig. 19). The height of the grouping on a vertical target compared to the depth of the grouping on the ground is of course proportionate to the tangent of the angle of descent; hence, small as is the group on a vertical target at 500 yds., the beaten zone is no less than 320 yds. deep. For the same reason, as the range, and consequently the angle of descent, increases, the beaten zone diminishes in depth. Another factor is the “dangerous space.” This is the space between “first catch,” i.e. the point at which the bullet (in a sheaf, the lowest bullet) comes low enough to catch a man’s head, and “first graze,” that at which it strikes the ground. The extent of this dangerous space varies of course with the height of the man’s head. In the case of a mounted man, at 1000 yds., it is 105 yds., while in that of a sharpshooter lying down, it is only 13 yds. (in addition of course to the beaten zone). As nowadays nearly all targets, on service, are lying or three quarters concealed figures, the dangerous space as compared with the beaten zone is at such a range too small to count as a factor. It is, however, important at shorter ranges, 500 yds. and under (700 and under with the new pointed bullets). Here the advantages of flat trajectory make themselves felt. Within this distance the bullet is at no point in its career too high to be dangerous to a standing man or a horseman. A lying figure is in danger at any distance beyond 350 yds. if the sights are set to 500 yds. (front half of effective zone 110 yds., dangerous space 52 yds.). This is the theory underlying the 500 yds. “fixed sight” or “battle-sight,” a setting which holds good for all less ranges, and can be put on the rifle instantly and without looking at the back-sight graduations. EB1911 - Rifle - Fig. 19 Beaten Zone.png

EB1911 - Rifle - Fig. 20 Trajectories.png

These facts, taken in conjunction with the imperfections of the most skilful individual marksmanship and the chances of wrong estimation of distance, are the basis of the musketry training and practice of to-day. At the School of Musketry, Hythe, the standard of judging distance is “not more than