Manual of Military Training Part 119

The selection of a defensive position presents this question: _Shall it be near the crest or well down the slope?_

A position well down the slope

_Advantages:_

1. The depth of the beaten zone for fire delivered from the position is increased and the upper portion of the cone of fire will include the supports and reserves advancing to reenforce the hostile firing line. That is to say, the fire will be a _grazing fire_.

2. It eliminates dead s.p.a.ces that might otherwise exist at the bottom of the slope.

3. The hostile fire being directed against a point well down the slope, the high ground in rear will interpose as a defilade and intercept the upper portion of the cone of fire which might otherwise take effect on the supports and reserves behind the crest.

_Disadvantages:_

1. It makes withdrawal difficult in case it becomes necessary to fall back.

2. It is difficult to reenforce the firing line.

A position near the crest

_Advantages:_

1. It favors observation of the enemy.

2. It makes withdrawal easy in case it becomes necessary to fall back.

3. It is easy to reenforce the firing line by the supports advancing from behind the crest.

_Disadvantages:_

1. The depth of the beaten zone is decreased and consequently the cone of fire will probably not include the supports and reserves advancing to reenforce the hostile firing fire. In other words, the fire will be a _plunging fire_.

2. It is likely to result in dead s.p.a.ces at the bottom of the slope.

3. It affords a good target for the hostile artillery.

Whether or not a position near the crest or a position down the slope should be chosen, depends, in each case, upon circ.u.mstances.

For instance in a rear guard action, where a determined stand is not contemplated, a position near the crest would be occupied. On the other hand, if a determined stand were contemplated, the terrain offered good opportunity for the delivery of an effective grazing fire, and we had reason to believe that we were going to be subjected to heavy artillery fire, a position at the foot of the slope would be selected.

However, it may be said that, in general, a defensive position should be near the bottom of the slope.

=1427. Gentle reverse slopes.= From the point of view of avoiding losses, all gentle reverse slopes are dangerous and are to be avoided when possible.

When necessary to traverse or to occupy such ground, precautions must be taken to protect the reserves or other bodies of troops by placing them on the flanks; by disposing them in formations with a narrow front; by causing them to lie down; by the construction of suitable shelter, and by avoiding useless movements.

Adjustment of Fire

=1428. Fire at stationary targets.= The correct adjustment of fire is attained by causing the center of impact to fall on the center of the target. This is the problem constantly presented in combat firing.

The two important elements entering into this problem are, (1) the commander and (2) the troops. When a body of troops has aimed correctly at the target indicated, with the elevation ordered and has fired with steadiness, it has done all that can be expected of it, but that is not sufficient; for, if the commander, by giving the wrong sight-setting, for example, has failed to cause the center of impact to fall on the center, of the target, the result may be nothing.

Hence the vital importance of knowing and announcing the correct range.

It is known that good shots make a small group and poor shots a large group, average shots making a group of intermediate size.

It is frequently stated that troops composed of good shots are not so effective in collective firing as poorer shots. How is this possible?

The explanation is simple. The shot group of the good shots is small and if misplaced by an error in range estimation few hits result while the shot group of poorer shots, being larger, is not so much affected by the same error in range estimation, will cover the ground, and probably hit more figures. This, of course, is _only true_ when a considerable error has been made in estimating the range.

As battle targets are mostly line targets, a displacement to the right or left does not amount to much, but an error in depth (range), as stated before, is serious. Thus we, see that the _correct determination of the range_ is very important.

=1429. Determination of range.= The range may be determined, with only a small error, by a range finder. There are several other methods, as, for instance, by trial shots,--the dust thrown up by the bullet showing whether the range is too short or too great,--by sound, by the appearance of objects, etc., but except in deliberately prepared defensive positions, estimating by eye will be the most practicable method of estimating the range. For all practical purposes a very satisfactory result will be obtained by taking the average estimates of several trained men.

In observing the effect of the fire the ground may be wet, or covered with turf, sod or brush in which no signs of striking shots can be seen. By careful use of good field gla.s.ses some indication of the place where the shots are going, may be obtained. The actions of the enemy may often indicate whether the fire is effective or not.

=1430. Combined sights.= All other means failing, _combined sights_ may be resorted to. By this is meant firing part of the troops with sights set at one range and part with a range greater or less by 100 yards or more. This increases the beaten zone and will generally a.s.sure a certain amount of fire effect. This method is seldom used under 500 yards.

=1431. Auxiliary aiming points.= It frequently happens that the target is so well concealed that it is invisible. In this case some well defined object in front or behind it must be used as an _aiming target_, and the range given so that the beaten zone will include the actual target at its center.

=1432. Fire at moving targets.= In firing at a moving enemy, a beaten zone must be established immediately in front, his forward movement into this zone completing the adjustment of fire. Due to the chance of overestimating the range, a sight-setting must be taken _well under_ the estimated range (usually about 200 yards against advancing infantry).

When the fire becomes effective, as may be judged by the actions and movements of the enemy, the rate of fire should be quickened in order to increase the effect of the fire.

Frequent changes of sight not only cause a loss of time, but they also multiply chances of error in sight-setting. Changes in sight-setting against advancing infantry should not be less than 200 yards at a time, that is to say, when the enemy has pa.s.sed through the zone of effective fire, the sight should be lowered 200 yards and the operation repeated until the battle-sight zone is reached, when the rear-sight leaf is thrown down and no other sight manipulation is made.

Against skirmish lines advancing by rushes, the sight-setting should not be changed during a rush, but it should be done at the halts, so that the greater vulnerability of the targets presented during the rush may be taken advantage of.

Against retreating infantry, use the estimated range, and when the target appears to have pa.s.sed beyond the zone of effective fire, add 200 yards to the sight-setting.

Against attacking cavalry, due to the rapidity of the advance, there will not usually be time for sight manipulation other than throwing down the rear-sight leaf, so that the battle should be resorted to at all ranges.

In firing at a target moving across the line of fire it is desirable, on account of the confusion caused thereby, to hit the head of the column. It is necessary, therefore, to hold to the front a distance sufficient to allow for the time of flight and the rate of march. This will be accomplished by the observance of the following rough rules:

1. Against infantry, hold against the head of the marching column;

2. Against cavalry at a trot, hold to the front 1 yard for every 100 yards of range; and at a gallop, 2 yards for every 100 yards of range.

=1433. Night firing.= In night firing it is almost impossible to adjust the fire by ordinary means.

In night attacks the purpose of the offensive is to gain rapidly and quietly a position where the issue may be decided in a hand to hand encounter, or a position from which the superiority of fire may be gained at daylight. For the offensive, therefore, fire action is a subordinate consideration.

On the defensive, when a night attack is apprehended, preparations should be made to sweep with fire the ground immediately in front over which the a.s.sailant must advance.

Special arrangements may sometimes be made for resting rifles on the parapet, so that the ground in front will be suitably covered. A solid support is necessary for maintaining the proper direction of the pieces during firing. For this purpose notched boards or timbers are convenient. The arrangements should be such that the operations of loading and firing may be performed without removing the rifles from the support.

Searchlight illumination may reveal the position and movements of the enemy sufficiently well to permit the use of the sights. In night operations of small parties fire may be well directed when a bright, well-defined light, such as a camp fire, is presented as an aiming point. In such a case a slight illumination of the front sight is required.