(iii) Targets moving directly Towards or Away from the Firer.—In aiming at an object moving directly towards or away from the firer, allowance for elevation will usually be made by aiming up or down—not by waiting to alter sights (Sec. 21, paras. 1 and 2).
Section 23.—Practice in Rapid Adjustment of Sights.[12]
1. This instruction should be carried out concurrently with instruction in loading in the various firing positions. Frequent small changes of sighting lead as a rule to loss of fire effect, and may be avoided by aiming up or down. But when there is time the sights will be adjusted for every alteration in the range, and aim will be taken at the lowest part of the mark. It is essential that men should be trained to adjust their sights accurately and rapidly, and that this power should become to all intents and purposes instinctive, so that this vitally important duty on which fire effect in a large measure depends will be carried out by the soldier with certainty in moments of the most extreme stress and excitement.
2. Training in Rapid Adjustment.—Instructors will frequently test their squads in setting their sights rapidly and accurately. They will give orders for aiming or firing at definite targets, but without naming the range, and require their squads to adjust their sights before they bring the rifle to the shoulder, judging the distance for themselves, which will help to make the careful adjustment of sights, which is essential for fire effect, habitual to the soldier. Adjustment of sights will also be practised under the same conditions in connection with the movement of the firer or the target, represented by fatigue-men.
3. Rules for Adjusting Sights.—(i) To Adjust the Backsight.—Hold the rifle in the loading position (Sec. 27), so that the lines on the backsight can be seen clearly. Press in the stud (or studs) on the side of the slide with the left or right hand; move the slide until the line is even with the place on the leaf giving the elevation for the distance named, taking care that it is firmly fixed. Charger-Loading Lee-Enfield Rifle.—Loosen the clamping screw with the thumb and forefinger of the right hand, move the slide until the top is even with the line on the leaf giving the elevation for the distance named, and then tighten the clamping-screw.
(ii) To Lower the Backsight.—Press the stud or studs inwards with the left or right hand, and draw the slide backwards as far as possible. Charger-Loading Lee-Enfield Rifle.—Loosen the clamping-screw, lower the slide to the bottom of the leaf with the firefinger and thumb of the right hand, then tighten the clamping-screw.
(iii) Fine Adjustment of the Backsight.—(a) S.M.L.E. Rifle, Marks III and IV.—Press the stud on the slide with the thumb of the left hand till the worm-wheel can be easily revolved; turn the worm-wheel with the thumb-nail of the right hand until the required elevation is obtained. The stud must not be pressed to such an extent that the worm-wheel is entirely disengaged from the rack.
(b) Other Marks.—Turn the fine adjustment screw with the forefinger and thumb of the right hand until the line on the leaf is level with the line on the fine adjustment scale giving the required elevation.
(iv) To Adjust the Long-Range Sights.—Hold the rifle in the loading position, so that the dial can be seen clearly. Move the pointer to the place on the dial giving the elevation for the distance named, and then raise the aperture sight.