Use the first joint of the forefinger to squeeze the trigger. It is the most sensitive and best controlled portion of the body. As you place the rifle to your shoulder, squeeze the trigger so as to pull it back about one-eighth of an inch, thus taking up the safety portion or slack of the pull. Then contract the trigger finger gradually, slowly and steadily increasing the pressure on the trigger while the aim is being perfected. Continue the gradual increase of pressure so that when the aim has become exact the additional pressure required to release the point of the sear can be given almost insensibly and without causing any deflection of the rifle. Put absolutely all your mind and will power into holding the rifle steady and squeezing the trigger off without disturbing the aim. Practice squeezing the trigger in this way every time you have your rifle in your hand until you can surely and quickly do it without a suspicion of a jerk.
By practice the soldier becomes familiar with the trigger squeeze of his rifle, and knowing this he is able to judge at any time, within limits, what additional pressure is required for its discharge. By constant repetition of this exercise he should be able finally to squeeze the trigger to a certain point beyond which the slightest movement will release the sear. Having squeezed the trigger to this point the aim is corrected, and when true the additional pressure is applied and the discharge follows and the bullet flies true to the mark.
Section 7. Firing positions.
When in ranks at close order the positions are those described in the Cavalry Drill Regulations. When in extended order or when firing alone these positions may be modified somewhat to better suit the individual. The following remarks on the various positions are offered as suggestions whereby steady positions may be learned by the soldier.
Standing position: Face the target, then execute right half face. Plant the feet about 12 inches apart. As you raise the rifle to the shoulder lean very slightly backward just enough to preserve the perfect balance on both feet which the raising of the rifle has somewhat disturbed. Do not lean far back and do not lean forward at all. If your body is out of balance, it will be under strain and you will tremble. The right elbow should be at about the height of the shoulder. The left hand should grasp well around the stock and handguard in front of the rear sight, and the left elbow should be almost directly under the rifle. The right hand should do more than half the work of holding the rifle up and against the shoulder, the left hand only steadying and guiding the piece. Do not try to meet the recoil; let the whole body move back with it. Do not be afraid to press the jaw hard against the stock; this steadies the position, and the head goes back with the recoil and insures that your face is not hurt.
Kneeling position: Assume the position very much as described in the Cavalry Drill Regulations. Sit on the right heel. The right knee should point directly to the right; that is, along the firing line. The point of the left elbow should rest over the left knee. There is a flat place under the elbow which fits a flat place on the knee and makes a solid rest. Lean the body well forward. This position is uncomfortable until practiced, when it quickly ceases to be uncomfortable.
Sitting position: Sit down half faced to the right, feet from 6 to 8 inches apart, knees bent, right knee slightly higher than the left, left leg pointed toward the target. Rest both elbows on the knees, hands grasping the piece the same as in the prone position. This is a very steady position, particularly if holes can be found or made in the ground for the heels.
Prone position and use of the gun sling: To adjust the sling for firing, unhook the straight strap of the sling and let it out as far as it will go. Adjust the loop so that when stretched along the bottom of the stock its rear end (bight) comes about opposite the comb of the stock. A small man needs a longer loop than a tall man. Lie down facing at an angle of about 60° to the right of the direction of the target. Spread the legs as wide apart as they will go with comfort. Thrust the left arm through between the rifle and the sling, and then back through the loop of the sling, securing the loop, by means of the keeper, around the upper left arm as high up as it will go. Pass the hand under and then over the sling from the left side, and grasp the stock and handguard just in rear of the lower band. Raise the right elbow off the ground, rolling slightly over on the left side. Place the butt to the shoulder and roll back into position, clamping the rifle hard and steady in the firing position. The rifle should rest deep down in the palm of the left hand with fingers almost around the handguard. Shift the left palm a little to the right or left until the rifle stands perfectly upright (no cant) without effort. The left elbow should rest on the ground directly under the rifle, and right elbow on the ground about 5 inches to the right of a point directly under the stock. In this position the loop of the sling, starting at the lower band, passes to the right of the left wrist, and thence around the left upper arm. The loop should be so tight that about 50 pounds tension is placed on it when the position is assumed. This position is uncomfortable until practiced, when it quickly ceases to be uncomfortable. It will be steadier if small holes can be found or dug in the ground for the elbows. In this position the sling binds the left forearm to the rifle and to the ground so that it forms a dead rest for the rifle, with a universal joint, the wrist, at its upper end. Also the rifle is so bound to the shoulder that the recoil is not felt at all. This is the steadiest of all firing positions.
The gun sling can also be used in this manner with advantage in the other positions.