The distance to the target must be determined as accurately as possible and the sights set accordingly.
Aside from training and morale, this is the most important single factor in securing effective fire at the longer ranges.
Except in a deliberately prepared defensive position, the most accurate and only practicable method of determining the range, in absence of a suitable mechanical range finder, will generally be to take the mean of several estimates made independently.
Estimation of ranges.—Five or six officers and men, selected from the most accurate estimators in the troop and designated as range estimators, should be specially trained in estimating distances.
Whenever necessary and practicable, the captain assembles the range estimators, points out the target to them, and adopts the mean of their estimates. The range estimators then take their customary posts.
When a range is announced, the men at once set their sights to correspond, and whenever practicable an examination of the pieces is made in order to verify the sight setting.
(C. C. D. R., No. 1, Apr. 26, 1917.)
Firing is delayed as long as possible for three reasons, viz: (a) At the extreme ranges little damage can be done on the enemy, and ineffective firing always encourages him; (b) halting to fire delays the advance, and the great object to be accomplished is to close in on the enemy where you can meet him on better terms; (c) plenty of ammunition will be required at the decisive stage of the fight, and it is very difficult to send extra ammunition up to the firing line. Therefore never fire until ordered to do so, and then never fire more than the number of rounds designated. Never fire after the command "cease firing" is given.
Ammunition in the bandoleers will ordinarily be expended first. Thirty rounds in the right pocket section of the belt will be held as a reserve, to be expended only when ordered by an officer.
Soon, however, it will be necessary to halt and open fire on the enemy in order to cause him some loss, to make his riflemen keep down in their trenches, and to make them fire wildly. It is probable that at this time and until you arrive much closer you will not see any of the enemy to fire at. You may not even see any trenches nor know just where the enemy is. Your higher officers, however, with their field glasses and the messages they receive, will know. Each troop will be assigned a certain front to cover with its fire. Therefore be careful to fix your sights at the designated range and fire only at the designated target. This means team work in firing, which is one of the most important elements of success.