COVERING FIRE
Machine guns will often be used to cover the advance of infantry from “long” to “effective” range when the artillery is still occupied in the artillery duel and the infantry first come under effective rifle fire from the enemy. The ease with which they can instantly open and cease fire, concentrate on a particular spot, or sweep a line of trenches, renders them particularly suited for this purpose, and the Japanese constantly used them to keep down the enemy’s rifle fire in this manner during the late war.
The narrow beaten zone enables them to fire safely over the heads of advancing infantry from all ranges beyond 800 yards, provided the infantry are at least 200 yards from the enemy fired at. A study of the table of trajectory in the Appendix to Manual of Military Training will enable the machine gunner to decide the circumstances under which the fire is safe in each case.
Positions on the flanks and if possible to the front of the advancing infantry will render covering fire most effective, but these positions will rarely be possible. The first consideration is the concealment of the gun from the enemy’s artillery, which can easily silence them if exposed. It is also necessary that the positions selected should be sufficiently commanding to enable the battery commander to see the attacking infantry during the whole advance, so as to fire only when they are moving, while at the same time he must be able to see the position of the enemy’s trenches and thus direct the fire on any part desired.