Terminology

Question 1

Trajectory

Answer 1

The path that a projective in flight takes from the muzzle of the weapon to the point of
impact.
As the range to the target increases, so does the curve of trajectory.

Question 2

Maximum Ordinate

Answer 2

The highest point above the line of sight the trajectory reaches between the muzzle of the
weapon and the base of the target. It always occurs at a point two-thirds (2/3) of the distance
from the weapon to the target and increases with range.
→ Like trajectory, maximum ordinate increases as the range increases.

Question 3

Cone of Fire

Answer 3

The cone of fire is the pattern formed by the different trajectories in each burst as they travel
downrange. The pattern that these rounds create on the way to the target is the Cone of Fire.
→ Vibration of the weapon and vibrations in the ammunition and atmospheric conditions all
contribute to the trajectories that make up the cone of fire.
→ It is the space that the rounds occupy in flight.

Question 4

Beaten Zone

Answer 4

The beaten zone is the elliptical pattern formed when the rounds within the cone of fire strike
the ground or target.

Question 5

2 means of adjusting fire

Answer 5

Primary:
▪ Observing the Beaten Zone.

Secondary:
▪ Observing tracers if you cannot observe the Beaten Zone.

Question 6

Effective Beaten Zone

Answer 6

• Because of dispersion, only that part of the beaten zone in which 85% of the
rounds fall is considered the effective beaten zone.

Question 7

Effects of range on beaten zone

Answer 7

As the range to the target increase, the beaten zone becomes shorter and wider.
Conversely, as the range to the target decreases, the beaten zone becomes longer
and narrower.

Question 8

Effects of slope on the beaten zone

Answer 8

On rising ground, the beaten zone becomes shorter but remains the same
width.
▪ On ground that slopes away from the gun, the beaten zone becomes longer
but remains the same width.

Question 9

Danger space

Answer 9

This is the space between the muzzle of the weapon and the target where the trajectory rises less than 1.8 meters above the ground (1.8m is the average height of standing soldier) that
includes the beaten zone.

Question 10

Dead space

Answer 10

Any fold or depression in the ground that prevents a target from being engaged from a fixed position.

Question 11

Sector of Fire

Answer 11

A sector of fire is an area to be covered by fire that is assigned to an individual, a weapon, or
a unit.
→ Gunners are normally assigned a primary and a secondary sector of fire.

Question 12

Final Protective Fire (FPF)

Answer 12

A Final Protective Fire (FPF) is an immediately-available, prearranged barrier of fire to stop enemy movement across defensive lines or areas.

Question 13

Final Protective Line (FPL)

Answer 13

A FPL is a predetermined line along which grazing fire is placed to stop an enemy assault.
→ If a FPL is assigned, the machine gun is sighted along it expect when other targets are being engaged.

Question 14

Principal Direction of Fire (PDF)

Answer 14

A PDF is a direction of fire assigned priority to a gunner to cover an area that has good fields
of fire or has a likely dismounted avenue of approach.

Question 15

Primary sector of Fire

Answer 15

The direction of fire assigned to cover the most likely avenue of enemy approach from all
types of defensive positions.

Question 16

Secondary sector of Fire

Answer 16

The direction of fire assigned to cover the second most likely avenue of enemy approach.
→ It is fired from the same gun position as the primary sector of fire.

Question 17

Grazing fire

Answer 17

Automatic weapons achieve grazing fire when the center of the cone of fire does not rise
more than 1 meter above the ground and has a maximum range of 600 meters over level or
uniformly sloping terrain.

Question 18

Fire control

Answer 18

Predetermined targets, including the FPL or PDF, are engaged on order or by the Standard 
Operating Procedure (SOP). The signal for calling for these fires is normally stated in the 
defense order.

Question 19

Distribution of fire

Answer 19

Distributed fire is delivered in width and depth such as at an enemy formation.

Question 20

Concentration of fire

Answer 20

Concentrated fire is delivered at a point target such as an automatic weapon or an enemy
fighting position.