2011 rhb final revised 02-11-2011

WEAPON

M249

M240B

M2

MK 19

Field Manual

3-22.68

3-22.68

3-22.65

3-22.27

TM

9-1005-201-10

9-1005-313-10

9-1005-213-10

9-1010-230-10

Description

5.56-mm

7.62-mm

.50-caliber

40-mm

gas-operated

gas-operated

recoil-

aircooled,

automatic

medium

operated heavy

blowback-

operated

automatic GL

Weight

16.41 lbs

27.6 lbs

128 lbs

140.6 lbs

(gun w/barrel)

(gun w/ barrel)

(gun w/ barrel

(gun w/ barrel

16 lbs (tripod)

20 lbs (tripod)

and tripod)

and tripod)

Length

104 cm

110.5 cm

156 cm

109.5 cm

Maximum Range

3,600 m

3,725 m

6,764 m

2,212 m

Maximum Effective Range

Bipod/ point:

Bipod/point: 600m

Point: 1,500 m

Point: 1,500 m

600 m

Tripod/point: 800m

(single shot)

Area: 2,212 m

Bipod/ area:

Bipod/area: 800m

Area: 1,830 m

800 m

Tripod/area:1,100m

Grazing: 700 m

Tripod/ area:

Suppression:

1,000 m

1,800 m

Grazing: 600 m

Grazing: 600 m

Tracer Burnout

900 m

900 m

1,800 m

-

Sustained Rate of Fire

50 RPM

100 RPM

40 RPM

40 RPM

Rounds/ burst

6 to 9 rounds

6 to 9 rounds

6 to 9 rounds

Interval

4 to 5 sec

4 to 5 sec

10 to 15 sec

Barrel change

Every 10 min

Every 10 min

End of day

or if damaged

Rapid Rate of Fire

100 RPM

200 RPM

40 RPM

60 RPM

Rounds/ burst

6 - 9 rounds

10 - 13 rounds

6 - 9 rounds

Interval

2 - 3 sec

2 - 3 sec

5 - 10 sec

Minutes to barrel change

2 minutes

2 minutes

Change barrel end

of day or if

damaged

Cyclic Rate of Fire/

850 RPM,

650 - 950 RPM,

450 - 550 RPM,

325 – 375

Minutes to barrel change

continuous

continuous burst/

continuous burst

RPM,

burst/ min

min

continuous

burst

Table 10-2. MACHINE GUN TERMS

Line of Sight

The imaginary line drawn from the firer's eye through the sights to the point of aim.

Burst of Fire

A number of successive rounds fired with the same elevation and poi nt of aim when the trigger is

held to the rear. The number of rounds in a burst can vary depending on the type of fire employed.

Trajectory

The curved path of the projectile in its flight from the muzzle of the weapon to its impactAs.the

range to the target increases, so does the curve of trajectory.

Maximum

The height of the highest point above the line of sight the trajectory reaches between the muzzle of

Ordinate

the weapon and the base of the target. It always occurs at a pointabout two-thirds of the distance

from weapon to target and increases with range.

Cone of Fire

The pattern formed by the different trajectories in each burst as they travel downrange. Vibration of

the w eapon and v ariations i n am munition and at mospheric conditions al l c ontribute t

o t he

trajectories that make up the cone of fire.

Beaten Zone

The elliptical pattern formed when the rounds in the cone of fire strike the ground or target. The size

and shape of the beaten zone change as a function of the rangeto and slope of the target, but is

normally oval or cigar shaped and the density of the rounds decreases toward the edges. Gunners

and automatic riflemen should engage targets to take maximum effect of the beaten zone. Due to

the right-hand twist of the barrel, the simplest way to do this is to aim at the left base of the target.

Sector of Fire

An area to be c overed by fire that is assigned to an i ndividual, a w eapon, or a unit. Gunners are

normally assigned a primary and a secondary sector of fire.

Primary Sector

The primary sector of fire is assigned to the gun team to cover the most likely avenue of enemy

of Fire

approach from all types of defensive positions.

Secondary

The secondary sector of fire is assigned to the gun team to cover the second most likely avenue of

Sector of Fire

enemy approach. It is fired from the same gun position as the primary sector of fire.

Final Protective

An i mmediately av ailable, pr earranged barrier of fire t o s top enemy movement ac ross defensive

Fire (FPF)

lines or areas.

Final Protective

A pr edetermined l ine al ong w hich gr azing f ire i s pl aced t o s top an enemy assault. I f an F PL

i s

Line (FPL)

assigned, the machine gun is sighted along it except when other targets are being engaged. An FPL

becomes the machine gun's part of the unit's final protective fires. An FPL is fixed in direction and

elevation. However, a small shift for search must be employed to prevent the enemy from crawling

under the FPL and to compensate for irregularities in the terrain or the sinking of the tripod legs into

soft soil during firing. Fire must be delivered during all conditions of visibility.

Principal

Assigned to a gunner to cover an area that has good fields of fire, or that has a l ikely dismounted

Direction of Fire

avenue of approach. A PDF also provides mutual support to an adj acent unit. If no F PL has been

(PDF)

assigned, then sight machine guns using the PDF. If a P DF is assigned and other targets are not

being engaged, then machine guns remain on the PDF. It is used only if an FPL is not assigned; it

then becomes the machine gun's part of the unit's final protective fires.

Grazing Fires

Automatic w eapons

graze f ire w hen t he c enter of

t he c one of f ire f ails t o r ise m ore t ha

aboveground. Grazing fire is employed in the final protective line (FPL) in defense. It is possible only when

the terrain is level or uniformly sloping. Any dead space encountered along the FPL must be c overed

by

indirect fire, such as

from an M 203. When firing over

level or uniformly sloping terrain, the machine

M240B and M249 can attain a maximum of 600 meters of grazing fire. The M2 can attain a maximum of 700

meters.

Plunging Fires

Plunging fire occurs when there is little or no danger space from the muzzle of the weapon to the beaten

zone. It occurs when weapons fire at long range, from high to low ground, into abruptly rising ground,

or

across uneven terrain, resulting in a loss of grazing fire at any point along the trajectory.