4. The soldier must be made to realize that the results of errors of marksmanship due to these various causes increase in extent as the range increases, and that they reach their maximum at longer ranges; that is to say, targets become smaller and more difficult to see and to aim at, their range becomes harder to estimate, and the accuracy of fire for other reasons stated becomes less as the range increases. Therefore, the effect of individual fire decreases as the range increases. It is easily possible for instructors in the course of lectures on this point to make it sufficiently clear to men that, under service conditions at longer ranges, effect must be obtained from collective fire rather than from individual fire, for all the above reasons. In some degree this important principle of the science of modern warfare can be demonstrated by firing at service targets on full distance and also on miniature ranges (see Chapter X).
Section 12.—Dispersion of Individual and Collective Fire.
1. Shot Groups.—Owing to errors on the part of the firer, and also to imperfections in the rifle and ammunition, it is found that a series of shots, even when fired by an individual under perfect conditions at a large, stationary, distinct target at a known and close range, do not all strike the point aimed at, but they form a group of shot-marks about this point, the density of which varies mainly with the skill of the firer.
2. Cone of Fire ([Fig. 6]).—It is evident that the trajectories of these shots will not coincide, but will together form a figure termed “the cone of fire.” It is also clear that, when aim is well directed, the bullets of a cone of fire should always strike an object so long as the shot group formed by it is either smaller or of the same size as the object aimed at. But when the shot group is spread over a larger surface than the size of the object, shots must necessarily miss the mark in proportion as the size of the grouping exceeds that of the object aimed at.
Fig. 6. Cone of Fire
A—B shows the dangerous space due to height of objective.
Note:-The Dangerous Space will vary with height of objective. The curve of the Trajectory is imaginary and not accurate for any distance.
3. Dispersion of Individual Fire.—It is clear, therefore, that the dispersion of individual fire explained in para. I will of itself, apart from the various factors mentioned in Sec. II, militate against the assurance of fire effect by individual fire at longer ranges, because the dispersion of fire will become greater as the target decreases in size, owing to distance, and the shot group will consequently be spread over a much larger surface than that of a long-range service target, even if stationary and visible to the naked eye.
4. Dispersion of Collective Fire.—When a body of soldiers fires with the same elevation at the same object, the dispersion of shots is accentuated by the varying skill and eyesight of the men, with the result that the cone formed will be of larger dimensions than in the case of individual fire. The dimensions of the cone of fire will again be further increased if the firers are from any cause, such as fatigue or excitement, unsteady; if the rifles are in bad condition or the target indistinctly seen—factors which are all incidental to firing under the conditions of active service.