2. Need for Mental Effort.—Trigger-pressing requires most careful individual instruction, during which the necessity for determination and strong personal effort of will will be impressed on the mind of every recruit. The power of concentrating the mind and controlling the nerves and muscles by exercising the will are all developed by practice in trigger-pressing, and these qualities of character are essential for good shooting and for fire discipline.
3. Rules for Trigger-Pressing.—(i) The trigger of the S.M.L.E.rifle has a double pull-off, and two distinct pressures are necessary to fire the rifle. The first pull should be taken when the rifle has been brought into position for aiming; the second when the sights are aligned on the mark. The charger-loading Lee-Enfield rifle has a single pull-off.
Fig. 15.—Method of Pressing Trigger with Forefinger.
(ii) The direction of the pull-off is diagonally across the small of the butt. The first joint of the forefinger should be placed round the lower part of the trigger ([Fig. 15]). In order not to disturb the aim breathing must be restrained when pressing the trigger. In firing the trigger must be pressed so as to release the cocking-piece without disturbing aim.
(iii) To do this a gradually increasing pressure must be exerted on the trigger until the spring is released. Such pressure will be facilitated if the grip of the trigger hand on the rifle is strengthened slightly, as though to oppose the inward pressure of the trigger finger with an equal gradual counter-pressure. This will give the whole action the effect of a squeeze with the hand, of which the pressure of the trigger finger is the most important part—the part on which the mind must be concentrated. On no account must the pressure of the finger in any degree take the form of a pull or jerk.
(iv) [Fig. 16] shows the results of faulty trigger-pressing in firing. The trigger has been pulled or jerked to the left instead of being properly pressed, and the grouping of shots—low to the right—shows how aim has been disturbed in consequence.
4. Method of Instruction.—(i) The rifle will be rested on sandbags ([Fig. 17]), or an aiming-rest, and the recruit will be seated with his elbows rested on a table. The instructor will first see that the recruit can move his trigger-finger independently of the remainder of the hand and arm, if necessary, by making him practise this action.
Fig. 16.—Shot Group illustrating Result of Faulty Trigger-Pressing.