Machinegun employment Flashcards
What are the classes of fire?
- Respect to the ground
- Respect to the weapon
- Respect to the target
What is trajectory?
The path of the fired round in flight to the target
What is maximum ordinate?
The highest point of the trajectory between the muzzle of the weapon and the base of the target
When does the maximum ordinate occur in the trajectory?
About 2/3 of the distance between the muzzle of the weapon and the target
Explain cone of fire…
Each round fired in a burst from the same weapon has a slightly different trajectory. The pattern these rounds create on the way to the target is the cone of fire
How is the cone of fire created?
By vibrations of the gun, variations in ammunition, and variations in atmospheric conditions
What are the two ways to determine round impact?
- The beaten zone (primary)
2. Tracer rounds (secondary)
What is danger space?
The space between the gun and target where the trajectory rises less than 1.8m (average height of a man) from the ground
What are the two types of fire in respect to the ground?
- Grazing fire
2. Plunging fire
What is grazing fire?
Fire that occurs when the center of the cone of fire rises less than 1m off the ground
What is plunging fire?
Fire that occurs when DANGER SPACE is within the beaten zone. Plunging fire occurs at longer ranges when firing from high ground onto low ground or when firing onto abruptly rising ground
What are the six classes of fire in respect to the weapon?
- Fixed
- Traversing fire
- Searching fire
- Traversing and searching fire
- Swinging traverse
- Free gun
Define “fixed” fire
Fire delivered against a point target when depth and width of the beaten zone covers the target. Only one point of aim is needed to provide target coverage
Define “traversing” fire
Fire distributed in WIDTH with successive changes in direction. The gunner selects several aiming points throughout the width of the target that are close enough to provide coverage without wasting ammunition
Define “searching” fire
Fire distributed in DEPTH by changes in elevation. The gunner selects several points of aim. Changes to aim points depend on the range/slope of the ground
Define “traversing and searching” fire
Fire distributed in WIDTH and DEPTH by making changes in elevation and direction. Provides good target coverage
Define “swinging traverse”
Wider distance covered with distribution of fire laterally; no changes in elevation or range. Targets usually have great width.
Define “free gun”
Fire distributed against a target that requires rapid, major changes in direction AND elevation that are difficult to make with the T and E
What are the four types of fire in respect to the target?
- Frontal fire
- Flanking fire
- Oblique fire
- Enfilade fire
Define “frontal fire”
Frontal fire occurs when the long axis of the beaten zone is at a right angle to the front of the target (e.g firing at the front of a target)
Define “flanking fire”
Flanking fire occurs when firing at the side of a target
Define “oblique fire”
Oblique fire is when the long axis of the beaten zone is at an angle other than a right angle to the front of the target
Define “enfilade fire”
Enfilade fire is when the long axis of the beaten zone coincides with the long axis of the target. This type of fire is either frontal or flanking. It is the most desirable type of fire with respect to a target, because it makes maximum use of the beaten zone
What class of fire (in respect to the weapon) is used for point targets?
Fixed fire
What technique and class of fire (in respect to the weapon) is used for area targets, e.g. linear targets with depth?
Aim center mass, traverse and search to either flank and then reverse to the other flank. Work from the center-out.
Target engagement technique for linear targets (i.e. targets with WIDTH)?
Initial point of aim is the target’s midpoint; using traverse fire, work from center-out
Target engagement technique for deep targets (i.e. targets with DEPTH)?
Initial point of aim is the target’s midpoint; using searching fire, work from center-out
How do gunners work in pairs?
When engaging targets, each gunner fire on his half of the target. The gunners DIVIDE THE TARGET IN HALF. They then divide each respective half into two sections. Using the midpoint reference of each section, both gunners distribute fire by applying the direction and elevation changes for best coverage, working their way from the middle of their respective sections out to the left/right limit of their target, and then back inward. A rapid rate of fire is used after fire superiority is gained, talking the guns.
What is the purpose of “talking guns?”
By default, it give a sitrep on the other friendly gun teams (e.g. that their gun is up and ammunition is not black). Also, conserves ammunition
What are the keys to overhead fires?
- Coordination
- Communication
- Situational awareness (SA)
What gun configuration is required for overhead fires?
Fires must be delivered from a tripod or vehicle mount using a T&E device
Explain the “gunner’s rule”
The “gunner’s rule” is applied when friendlies are at least 350m in front of the gun and the range to the target from the gun is 850m or less
“Old” method (preferred)
- Set the gun and put the rear sight to the proper range
- Without disturbing the lay of the gun, set the rear sight to 1600m
- Look through the rear sight and notice where the new line of aim meets the ground; this is the limit of troop safety. When friendlies reach this point, fires must be shifted or lifted
What are some safety measures for overhead fires?
- Securely emplace tripods
- Use field-expedient stops to avoid barrel dipping
- Avoid overhead obstacles
- Ensure entire gun crew knows safety limits
- Use good, reliable barrels
Define “defilade position”
When a gunner and his crew are completely masked by terrain
What does a defilade position require?
An observer to the rear of the gunner’s position, along the target line
What are some methods of fire control?
- Verbal
- Hand and arm signals
- Prearranged signals
- Personal contact
- Range cards
- Standard operating procedures (SOPs)
What are the six elements of fire commands?
ADD-RMC
- Alert
- Direction
- Description
- Range
- Method of fire
- Command to fire
What are the eight principles of machine gun (MG) employment?
PIC-M-DEEP
- Pairs
- Interlocking fires
- Coordinating fires
- Mutual support
- Defilade
- Enfilade
- Economy of Ammunition/Force
- Protection
How are gun teams best employed in defense?
- Make use of channelizing obstacles
- Mutually supported by other weapons
- Guns have primary, alternate, and supplementary positions
What are the rates of fire for the M249 SAW?
Sustained - 50rpm w/ 3-5rd bursts; barrel change every 10 minutes
Rapid - 100rpm w/ 6-8rd bursts; barrel change every two minutes
Cyclic - 850rpm; barrel change every minute
What are the rates of fire for the M240B?
Sustained - 100rpm w/ 6-9rd bursts; barrel change every 10 minutes
Rapid - 200rpm w/ 10-12rd bursts; barrel change every two minutes
Cyclic - 650-950rpm; barrel change every minute
What are the rates of fire for the M60?
Sustained - 100rpm w/ 6-9rd bursts; barrel change every 10 minutes
Rapid - 200rpm w/ 10-12rd bursts; barrel change every two minutes
Cyclic - 550rpm; barrel change every minute
What are the two techniques for air defense for machine guns?
- Football field technique
2. Reference point technique
What are the two methods of measurement for the football field technique?
Fast-movers = 2 football fields Slow-movers = 1/2 football field
What are the three assault firing positions for machine guns?
- Hip
- Underarm
- Shoulder
What are the three types of wire obstacles?
- Protective wire
- Tactical wire
- Supplementary wire
What is the ideal placement of protective wire?
Protective wire is placed outside of the defensive trace and outside of hand grenade range (35m)
What is the ideal placement and function of tactical wire?
Tactical wire is placed on the friendly side of the final protective line (FPL); It gives defensive gun positions enfilade fire
What is the ideal placement and function of supplementary wire?
Supplementary wire disguises tactical wire and channelizes the enemy into tactical wire
What sector does an alternate fighting position cover?
The same sector as the primary position
What sector does a supplementary fighting position cover?
A different one than the primary/alternate position
Define sector of fire
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.
Who covers the primary sector of fire?
Usually the gun team covers the primary sector of fire
What does the secondary sector of fire cover?
The second most likely enemy avenue of approach
What is an FPF?
A Final Protective Fire (FPF) is an immediately available prearranged barrier of fire to stop enemy movement across defensive lines or areas.
What is the FPL?
An Final Protective Line (FPL) is a predetermined line along which grazing fire is placed to stop an enemy assault.
How is an FPL set up and assigned?
If an FPL is 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
What is a PDF?
A Principal Direction of Fire (PDF) is a direction of fire assigned priority to cover an area that has good fields of fire or has a likely dismounted avenue of approach. It also provides mutual support to an adjacent unit
How and when is a PDF used?
Machine guns are sighted using the PDF if an FPL has not been assigned. If a PDF is assigned and other targets are not being engaged, machine guns remain on the PDF
On the M122 tripod’s T&E mechanism, what value is the scale graduated in?
5 mil increments
What values does the scale on the M122 tripod’s traversing bar go to on the left and right?
Left: 100-450 mils
Right: 100-425 mils
What is the total value of mils on the M122 tripod’s traversing bar?
875 mils total
What is the range of mils on the traversing hand wheel on the M122 tripod?
100 mils of total movement
What is the range of mils on the elevating hand wheel on the M122 tripod?
50 mils total
What is the range of mils on the elevating bar on the M122 tripod?
Up: 200 mils
Down: 200 mils
Total: 400 mils
What is the military designation for the standard range card?
DA Form 5517-R
What is the range on the elevation scale of the M192 tripod?
0-530 mils
What is the range on the traverse scale of the M192 tripod?
0-900 mils
How many mils does one full handle manipulation on the M192 tripod equal?
Approximately 5 mils
Is the M192 tripod one mil adjustable? One mil readable?
The M192 tripod is one mil readable but NOT one mil adjustable
Define “beaten zone”
The beaten zone is the elliptical pattern formed by the rounds striking the ground or the target.
What causes changes to the size and shape of the beaten zone?
The size and shape of the beaten zone changes when the range to the target changes or when the machine gun is fired on different types of terrain.
How does the gunner determine “dead space” and “grazing fire?”
In the preferred method, the machine gun is adjusted for elevation and direction. A member of the squad then walks along the FPL while the gunner aims through the sights. In places where the soldier’s waist (midsection) falls below the gunner’s point of aim, dead space exists.
What are the characteristics of fire?
- Trajectory
- Maximum ordinate
- Cone of fire
- Beaten zone
- Danger space
What are the minimum components needed for a standard range card?
- Weapon symbol
- Sector of fire.
- PDF or FPL.
- Range, azimuth, and number label to predetermined targets.
- Dead space.
- Distance and azimuth from a known point or eight-digit grid coordinate (reference point).
- Magnetic north arrow.
- Data section.
When is the range card prepared?
The range card is prepared immediately upon occupation and is constantly revised
How many copies of the range card are made and for whom?
Two, one for the gunner and one for the squad leader
