BOLT-- A mechanical device for blocking the breech
AUTOMATIC-- The self-powered action of a weapon,
and holding the cartridge in the chamber during
using recoil, gas, or blowback operation, that
firing to prevent rearward escape of gases.
produces a rapid and continuous burst of shots while
the trigger is depressed.
BORESIGHTING-- A process by which the axis of a
AXIS OF THE BORE-- An imaginary centerline of the
gun bore and the line of a gunsight are made parallel
or are made to converge on a point.
bore of a gun.
BOUNDARIES-- The battalion and company defense
AZIMUTH-- A direction in a horizontal plane.
areas that are limited because of terrain features and
BARRAGE-- Final protective fires of indirect fire
avenues of approach.
weapons.
Company boundaries immediately forward of the
BARREL-- A metal tube used to direct the bulletin its
FEBA assign responsibility for an avenue of approach
line of flight.
to a company, preferably the company most threatened
BASE (BASE UNIT)-- The element or unit in a tactical
by the avenue. Boundaries between companies extend
operation around which a movement or maneuver
forward of the FEBA, but stop short of the combat
is planned and performed.
outpost line (COPL). They extend to the rear far enough
to provide sufficient area for the companies to organize
BASE OF FIRE-- One or more units that give sup-
their defense in depth.
porting fire to an attacking unit and serve as the base
around which attack operations are carried out.
Establishing rear boundaries may become
necessary during fluid operations when infilltration and
BATTALION FORWARD DEFENSE AREA--
guerrilla activities are possible. Rear boundaries help
Portion of a battle area defended by front-line
the company coordinate and control its maneuvers and
companies; it extends to the limit of the rearward
fires.
extension of lateral boundaries of the front-line
companies.
BREECH-- The rear end of the barrel.
BATTERY-- The position of a weapon when cocked and
BREECHBLOCK or BREECH MECHANISM-- The
its recoiling parts are forwarded.
metal block used to seal the rear end of the bore
against the force of the charge; in small arms, the
BATTLE AREA-- The area in which the forward forces
breech mechanism is the bolt.
and their reserves are located; it is described by
coordinating points, flank boundaries, and
BRIDGEHEAD-- An area of ground taken and held in
sometimes a rear boundary.
enemy territory.
BATTLE POSITION-- The position on which the main
BULLET-- The projectile of a small-arms cartridge that
effort of defense is, or is to be made.
is discharged from a weapon toward a target.
BEACHHEAD-- A designated area on a hostile shore or
BURST OF FIRE-- A number of shots fired
territory which, when seized and held, ensures the
automatically with a single squeeze of the trigger.
continuous landing of troops and material, and
BURSTING CHARGE-- The force of an explosive that
provides maneuvering space for subsequent
breaks the casing of a projectile to produce a
projected operations into enemy territory; the
demolition, fragmentation, or chemical action.
physical objective of an amphibious or airborne
operation.
CADENCE-- A rhythmic rate of march at uniform step.
BEATEN ZONE-- The area on the ground or target on
CALIBER-- The diameter of the bore measured from
which the shots forming the cone of dispersion
land to land; usually expressed in decimal fractions
strike.
of an inch.
BLADE-- The front sight; usually a small piece of metal
CAM-- An inclined surface that imparts a desired motion
used in conjunction with the rear sight for sighting
to a sliding piece. (This is a generalized small-arms
the target.
definition.)
BLOWBACK-- The energy produced in a weapon by
CANNIBALIZATION-- The act of taking apart or parts
expanding gases and powder; it forces the cartridge
from an unserviceable piece of equipment to make
case rearward out of the chamber.
another piece of equipment serviceable.
AI-2
