FEEDING- The mechanical positioning of an individual round for subsequent insertion into the chamber of a weapon during the cycle or operation.

FIELD FORTIFICATION- Entrenchments, emplace-ments, and obstacles constructed in the field to increase the natural defensive strength of the terrain.

FIELD OF FIRE- The area that a weapon or group of weapons covers effectively with fire.

FIELD STRIPPING- Removal of the groups from a weapon; does not include disassembly of groups.

FILE- A single column of men or vehicles, one behind the other.

FINAL PROTECTIVE FIRES- The "all-out" fires of the defending unit fired as the enemy approaches close to the front-line positions.

FINAL PROTECTIVE LINE- A line along which interlocking bands of grazing fire are placed to stop enemy assaults. The line is placed at a pre-determined distance from all available weapons fixed in direction and elevation that are capable of delivery under conditions of visibility.

FIRE AND MANEUVER- The close coordination of the movement of a unit with its own fire or the fire of supporting weapons. This coordination enables a portion of the unit to move forward, while the remaining portion covers the forward movement by fire.

FIRE CONTROL- All operations connected with the preparation and application of fire to a target.

FIRE DIRECTION CENTER- The element of a command post, consisting of gunnery and communication personnel and equipment, by means of which the commander exercises fire direction and fire control.

FIRE MISSION- A target assigned to a unit or personnel manning a certain weapon or weapons with instructions as to the time and method of firing and placing fire on the target.

FIRE UNIT- A unit whose fire is under the immediate and effective control of one leader.

FIRING MECHANISM- The parts of a weapon that move together to cause the cartridge primer to be struck when the trigger is depressed.

FIRING POSITIONS- Defensive positions from which fire missions are carried out; they are designated primary, alternate, or supplemental

FIXED FIRE- Fire delivered on a point target.

FLANK- The right or left extremity of a unit; the element on the extreme right or left of the line; a direction at right angles to the direction a unit is facing.

FLANK GUARD- A security detachment that protects the flank of a body of troops on the march.

FLANKING FIRE- Fire delivered at right angles to the enemy flank.

FLAT TRAJECTORY- A trajectory having little or no curvature.

FORMATION- Arrangement of the elements of a unit in line, in column, or in any other prescribed manner.

FORWARD DEFENSE AREA- Portion of a battle area defended by front-line companies or platoons.

FORWARD SLOPE- The slope of elevated terrain in the direction of the enemy.

FREQUENCY- The band on which a unit is to operate its radio communications.

FRONT- The line of contact of two opposing forces; the length of space of an element or formation measured from one flank to the other; the direction of the enemy.

FRONTAL FIRE- Fire delivered perpendicular to the enemy (across his front).

FUZE- A device for setting off an explosive charge; a command or request to indicate the type of fuze action desired, such as delay, quick or time for the 60-mm mortar.

GAS OPERATED- The small-arms principle by which gas pressure from a fired cartridge activates the operating parts of a weapon using a piston and cylinder arrangement.

GAS PORT- A small hole drilled in the barrel to allow the expanding gases to strike the piston in the cylinder of a gas-operated weapon; sometimes called a vent.

GENERAL SUPPORT- The support given to a force as a whole and not to any particular subdivision thereof.

GRAZING FIRE- Fire in which the trajectory does not rise higher than the height of a man standing.

GRENADE SUMP- A circular hole large enough to accept the largest known enemy grenade; it slopes downward under the fire step in the fighting hole. Hand grenades thrown into the fighting hole are exploded in this sump; their fragmentation is restricted to the unoccupied end of the fighting hole.

GROOVES- The depressed areas between the lands (raised surfaces) in the bore; the cutaway portion of the rifling into which the jacket or rotating band of a bullet fits to impart rotation to the bulletin its line of flight.

GROUND ZERO- The point on the ground or directly above at which a nuclear weapon has exploded.

GROUP- Two or more parts or assemblies that either function together in a gun or are so closely related to one another that they should be considered as a unit.

GUERRILLAS- Combatants that are members of an organized and recognized military force whose activities normally are directed to harassing, delaying, or disrupting opposing forces; they normally wear civilian clothes.

GUIDE- The individual (base) upon which a formation, or an element thereof, regulates its march.

HAMMER- A lever that is swung around by spring pressure to strike the firing pin of a weapon.

HANGFIRE- A delay in the functioning of a propelling charge explosive train at the time of firing. In most cases the delay, though unpredictable, ranges from a split second to several minutes.

HEAD- The leading element of a column.

HEADSPACE- In small-arms weapons, the distance between the face of the bolt and the base of the cartridge when it is fully chambered and the bolt is locked.

H-HOUR- The hour an attack is to be launched, an assault wave is to land, or a movement is to begin.

INDIRECT FIRE- Fire delivered at a target that cannot be seen from the gun position.

INFILTRATE- To pass troops in relatively small numbers through an opening in the enemy's position or his field of fire or through territory occupied by other troops or organizations.

INITIAL POINT- A place at which various subdivisions of a command are required to arrive at the proper time to join a marching column.

INSURGENCY- Subversive political activity, civil rebellion, revolt, or insurrection designed to weaken and overthrow a duly constituted authority by its own people.

INSURRECTION- A rising up against an established authority by its own people.

INTERFERENCE- Natural or man-made radiation of electrical energy that causes difficulty in reception of radio signals.

INTERVAL- The lateral space between elements on the same line.

JAMMING- Deliberate interference intended to prevent reception of radio signals in a specific frequency band.

KEY TERRAIN- Land, the possession of which could prove decisive in combat.

LANDS- The spiral raised surface in the bore of a weapon.

LEAF SIGHT- A type of metallic sight in which the aperture is raised to operating position by being swung upward on a hinged leaf.

LEFT (RIGHT) FLANK- The extreme left (right) element or edge of a body of troops in relation to the enemy, regardless of the direction in which the body of troops is facing.

LIMITING POINT- The point along a line of resistance where the responsibility of one unit stops and that of another begins. Limiting points are placed on the boundaries between companies to indicate specific localities on the ground where the battalion command wishes the company commanders to coordinate their defense.

LINE- A formation in which the elements are abreast, except that a section or platoon is in line one behind the other when its squads are in line.

LINE OF DEPARTURE- A line designated to coordinate the departure of attack elements.

LISTENING POST- A one- or two-man post located forward of the battle position for the purpose of listening for enemy activity.

LOADING- The manual procedure of inserting a magazine, clip, belt, or single round into a weapon or its feeding mechanism and the subsequent action for feeding, cambering, or cocking; the physical placing of personnel, equipment, or supplies aboard their carriers.

LOCAL SECURITY- A security element, independent of any outpost, established by a commander to protect his unit against surprise and to ensure its readiness for action.

LOCKING LUGS- Metal projections on the bolt that cam into recesses cut in the sides of the receiver to lock a weapon before firing.

LOCKING RECESSES- Spaces cut in the side of the receiver into which the locking lugs of the bolt are rotated into locking position.

MACHINE GUN- An automatic, rapid-fire weapon that is fired from a mount.

MAGAZINE- A device that stores and supplies ammunition and feeds the ammunition by means of its own spring and follower.

MAIN ATTACK- The part of an attack where the commander concentrates the greater portion of offensive power.

MAIN LINE OF RESISTANCE- An imaginary line along the forward edge of the battle position designed to coordinate the fires of all units and supporting weapons.

MALFUNCTION- The failure of a weapon to function satisfactorily.

MARCH OUTPOST- A security echelon established by a unit on a march during short halts.

MARK- Call for fire on a specified location to orient the spotter or observer or to indicate targets.

MASK- A natural or artificial obstruction that gives shelter form or interferes with observation or fire.

MAXIMUM ORDINATE- The highest point of trajectory.

MEANS OF SIGNAL COMMUNICATION- The means by which a message is conveyed from one person or place to another.

MESSAGE- Any thought or idea expressed in brief form or in plain or secret language; prepared in a form suitable for transmission by any means of communication.

MILITARY CREST- The highest point near the top of a slope from which the entire valley below is visible.

MISSION- The specific task or duty assigned to an individual, weapon, or unit.

MOUNT- The stand on which a weapon is secured to hold it in position for rapid fire. A mount is either fixed (immovable) or flexible (movable). A flexible mount permits the weapon to move in azimuth and elevation.

MUZZLE- The front or forward end of the barrel; the mouth of the barrel.

MUZZLE VELOCITY- The speed at which a bullet travels when it leaves the muzzle of the barrel.

NAVAL LANDING PARTY- A force of naval personnel organized from a ship's complement for the conduct of ground-force operations ashore.