Figure 3-66.--Delivering of overhead fire.
handwheel. Also, it is used against targets that are
Overhead fire will not be delivered by use of these rules
moving so rapidly across the front of the gunner that he
at ranges less than 400 yards or greater than 1,800 yards.
or she cannot maintain effective fire while using the
The steps in using the GUNNER'S RULE are as
traversing handwheel.
follows:
FREE GUNFIRE is delivered from the tripod
1. Lay the gun on the target with the correct sight
mount against a target requiring rapid, major changes
setting to hit the target.
in direction and elevation that cannot be made with the
2. Without disturbing the lay of the gun, set the rear
traversing and elevating mechanism. Free gunfire can
sight at 1,500 yards.
also be used from a vehicular mount against a target that
cannot be adequately covered by selecting a series of
3. Look through the sights and note the point where
aiming points.
this new line of aim strikes the ground. If this point is
beyond the feet of friendly troops, you may deliver
All types of fire can be delivered with biped-,
overhead fire safely until the troops reach this point. It
tripod-, or vehicular-mounted guns except as follows:
is not safe to fire when they pass this point.
swinging traverse fire cannot be delivered with bipod-
or vehicular-mounted guns; free gunfire cannot be
The steps in the application of the LEADER'S
delivered with bipod-mounted guns.
RULE are as follows:
1. Select a point on the ground to which you believe
OVERHEAD FIRE
friendly troops can advance with safety.
2. Determine the range to this point by the most
Overhead fire with the rifle is safe when the ground
accurate means available.
affords protection to friendly troops or when the troops
3. Lay the gun on the target with the correct sight
are far enough below the line of fire (fig. 3-66). Whether
setting to hit the target.
or not overhead fire should be used in any particular case
is a matter of judgment.
4. Set the rear sight at 1,500 yards or at the
A machine gun on a tripod is capable of delivering
estimated range to the point plus 600 yards, whichever
accurate overhead fire because of the small, uniform
is greater, without disturbing the lay of the gun. Under
dispersion of the cone of fire. In the attack, the use of
no condition should the sight setting be less than 1,500
overhead fire permits the machine gun to support the
yards.
advance of the rifle units. To permit overhead fire on any
5. Note the point where the new line of aim strikes
target, pass the cone of fire over the heads of friendly
the ground. If it strikes at the selected point, that point
troops by a certain distance, called the MINIMUM
marks the limit of safety.
CLEARANCE. Two rules are prescribed by which the
minimum clearance may be determined: the
6. If the new line of aim strikes the ground short of
GUNNER'S RULE for ranges up to 900 yards and the
the selected point, troops can advance safely to the point
LEADER'S RULE for ranges greater than 900 yards.
where the line of aim strikes the ground and to an
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