M2/M3 BFV: FIRE CONTROL SYSTEM - OD1608 - LESSON 1/TASK 1
Boresighting is a procedure that establishes a relationship between
the lines of sight of the sighting equipment (the integrated sight
unit and the backup sight) and the lines of sight of the weapons
(25mm gun, 7.62mm coaxial machinegun, and missile launcher) at a
given range. Boresighting establishes the starting point from which
all mechanical adjustments are made.
This task describes the
procedures for boresighting the 25mm gun.
However, before the
specific procedures for boresighting are introduced, it is necessary
to be familiar with the major components to be boresighted.
2.
Major Components of the Fire Control System
The procedures for boresighting five major components of the Bradley
fighting vehicle fire control system will be described in this and
the four subsequent tasks. The 25mm gun, the 7.62mm machinegun, and
the tube-launched, optically-tracked, wire-guided (TOW) missile
launcher are the weapons to be boresighted. The sighting devices are
the integrated sight unit (ISU) and the backup sight.
a. Weapons.
The three main weapons of the Bradley fighting
vehicle are the 25mm gun, the 7.62 coaxial machinegun, and the TOW
missile launcher (figure 1 on the following page).
The vehicle is
also equipped with two grenade launchers, but these will not be
discussed here. Either the gunner or the commander can select, arm,
and fire the main weapons.
(1) 25mm Gun.
The 25mm gun is an externally powered, chain
driven weapon. It can be operated electrically or manually. It is
controlled for single shot and low and high automatic rates of fire.
At a low rate of fire, between 75 and 125 rounds are fired per
minute. At a high rate of fire, between 175 and 225 rounds are fired
every minute. The 25mm gun is fed by a metallic link belt, and can
fire
armor-piercing
(AP)
or
high-explosive
(HE)
ammunition. The selection of ammunition and rate of fire is made at
the weapon control box.
The ISU allows day and night vision for
aiming the gun.
2
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