Hand Grenades. Hand grenades are used to produce a short-range defensive barrage at a distance of about 30 yards in front of the trenches. For this purpose one grenade thrower is required for from 10 to 16 yards of frontage.
They are also used to establish centers of resistance; to protect important features of the lines, such as salients, machine gun or automatic rifle posts, command posts, listening posts, etc.
They are used to defend a barricade in a communicating trench. In this latter case the grenades may be thrown from a special bombing post established for that purpose or from an adjoining trench.
Rifle Grenades. Rifle grenades are employed to establish a barrage at a greater range than that of the hand grenade, being used up to as great a distance as 300 yards. The great advantage of the rifle grenade barrage is that it is under the control of the platoon leader and can be called into service immediately, which is not always true of the artillery barrage.
Several grenade rifles concentrated on a trench will stop hand grenade throwing from the same. Rifle grenades are usually shot from the cover trench immediately in rear of the fire trench.
Automatic-Machine Rifles. In the defensive the A.M.R’s are usually employed to obtain flanking fire from the firing line, but may be used in the cover trench and sometimes in shallow holes out in front. In interior fighting they are used to cover stretches of communicating trenches against an enemy that has penetrated the first line.
Riflemen. The riflemen are placed in the intervals between the specialists in the firing line. They are also used as snipers and as sentinels. These sentinels are not to be confused with watchers, who may or may not carry rifles.