Musketry (.303 and .22 cartridges) / Elementary training, visual training, judging distance, fire discipline, range practices, field practices

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2. In attack, such knowledge will assist them in adopting formations and directing the fire of their men to the best advantage. In defence, it will aid them to select the best positions for fire action, and will enable them to take steps to minimize the inherent disadvantages of these positions. In the following examples only plane surfaces, without undulations or accidents, are considered.

3. Level Ground.—As already stated, on level ground the zone beaten by collective rifle fire varies considerably with the range. The extent of this zone is further influenced by the inclination of the ground to the line of sight.

4. Rising Ground.—(i) The more steeply the ground rises with reference to the line of sight, the greater will be the decrease in the extent of the beaten zone. For example, when firing with Mark VI ammunition at ground rising 2, 5, and 10 degrees, the depth of the beaten zone at 1,500 yards range is decreased roughly by quarter, half, and two-thirds respectively ([Fig. 8]). Since the grouping of the bullets becomes closer as the upward slope of the ground increases, the effect of errors in estimation of range will be more serious, and as the bullets will fall at a steep angle the dangerous space will be proportionately reduced.

The Beaten zone is greatest on slope A-D, the Trajectory being practically parallel to the surface of the ground.

Fig. 8. The relation of Ground to Fire Effect.

Fig. 9. The relation of Ground to Fire Effect.

(ii) Formations, Supports, and Reserves.—As a general rule, therefore, on ground which rises with reference to the line of sight, troops should be drawn up in shallow formations, but supports and reserves may be nearer the firing-line than is normally advisable.

5. Falling Ground.—(i) When the ground beaten by bullets falls in respect of the line of sight, the depth of the beaten zone is augmented in proportion as the downward slope increases, until it reaches its greatest magnitude when the angle of the fall of the bullets is the same as the slope of the ground; or, in other words, when the trajectory is practically parallel to the ground surface ([Fig. 8], Depth of Zone, A—D). In these circumstances the fire becomes grazing ([Fig. 9]), and the extent of the dangerous space is nearly identical with the beaten zone.