axis in the direction of
the line of fire, as shown in Fig. 45.

[Illustration: Fig. 45]

In view of the fact that at the long ranges the angle of fall of the
bullets is much greater than at short ranges, it follows that at
short ranges the elliptical figure (beaten zone) is much more
elongated than at long ranges. In other words, the longer the range,
the shorter is the depth of the beaten zone. This is shown in Fig. 45.

=1414. Uncertainty and ineffectiveness of long-range fire.= It follows
from what has been said, that as the range increases the length of the
beaten zone decreases,--that is, a less depth of ground is held under
fire. That being the case, if an error is made in sight setting due,
for example, to an incorrect estimate of the range, the proportionate
loss of fire effect due to misplacement of the center of impact will
be greater as the beaten zone is less,--that is, as the range is
greater.

Furthermore, the difficulty of exact range determination increases
with the distance, the two influences combining to make long-range
fire uncertain and usually ineffective.

=1415. Zone of effective fire.= That portion of the ground which
contains the best 75 per cent of the shots in the beaten zone, is
called the _zone of effective fire_.

Effectiveness of Fire

=1416. Factors involved.= The effectiveness of fire depends upon these
three factors:

(1) The percentage of hits made;
(2) The number of targets hit;
(3) The time of execution.

That is to say, the effectiveness of fire is determined by the number
of enemies disabled or targets hit in a given time.

=1417. Percentage of hits.= By the percentage of hits is meant the
proportion of all the bullets fired that hit the targets. For example,
if 1000 bullets are fired and 750 hit the targets, then the percentage
of hits is 75.

The percentage of hits depends upon the dispersion, and this is
influenced by the precision of the arm, the range, the visibility of
the target, the atmospheric conditions, the training and instruction
of the troops, and upon their physical and moral state at the time. In
addition, the percentage of hits also depends upon the character of
the ground as favoring ricochet hits, upon the correct estimation of
the range and the proper designation of the target.

=1418. Number of targets hit.= The number of targets hit,--that is,
the distribution of fire,--may be affected by varying degrees of
visibility, as men