1. Since machine guns are unsuited for maintaining a continuous fire, they will usually best assist the infantry by withholding their fire during the earlier stages of the battle, so as to be able to intervene at more critical periods. Machine guns allotted to a protective detachment will, however, always be employed so as best to assist the detachment in its special duties (Field Service Regulations, Part I., Chap. V.).
2. It will depend upon the general situation whether the machine guns should be placed under the control of the brigade machine-gun officer or left with the battalions to which they belong. When the facilities for concealment and control at effective range are good, and the brigade is engaged in a decisive attack, the best results will usually be obtained by unity of command. By a timely concentration of fire machine guns may thus be the deciding factor in the struggle for superiority of fire.
When control is difficult, or when the brigade is extended over a wide front, it will usually be better to leave guns with their units.
3. It will often be advisable to employ both methods and to leave their machine guns with the battalions which are first extended, while those of reserve battalions are placed under the command of the brigade machine-gun officer.
4. Although machine guns can move with deployed infantry under fire, they should rarely attempt to keep pace with attacking infantry. When they have gained a position from which they can effectively support their infantry in the struggle for fire superiority and in the assault, they should only be moved for good and sufficient reasons. The difficulties of ranging and of concealment on the move usually outweigh the advantages of decreasing the range.
5. Machine guns will usually find opportunities for employment in the attack in assisting the advance of their infantry by means of covering fire; in protecting attacking infantry against counter-attack or against cavalry; in assisting the infantry in the fire fight, and in preparing for the assault by sudden bursts of converging fire against the objective of the attack. They will also be of value in securing localities which have been seized during the advance, and can assist local reserves in acting as points of support to the attack.
Machine Guns in Defence
1. In defence, as in attack, the fire of machine guns should usually be withheld until the more critical stages of the battle. Premature opening of fire is liable to expose the position of the machine guns to the enemy’s artillery.
2. Machine guns may either be dispersed to command approaches, defiles, exits from woods, etc., by which the enemy may advance, to occupy advanced posts, and to bring enfilade fire to bear upon salients and upon the ground in front of weak parts of the position, or they may be massed and employed under the orders of commanders of sections.
3. When the guns are massed the alternative positions, Sec. 167 (D) 1, should be such that the firing line can be assisted during the crisis of the fight, and the advance of local and decisive counter-attacks can be covered and prepared. When covered approaches can be provided, massed machine guns should usually be withdrawn, after they have achieved their immediate object, and should await another favourable opportunity for action.