M2/M3 BFV: FIRE CONTROL SYSTEM - OD1608 - LESSON 1/TASK 1
begin. When choosing a target for boresighting of the 25mm gun, keep
in mind that a square shape makes the best target for boresighting.
Briefly, the boresighting procedure will be accomplished as follows:
the vehicle will be positioned and the gun aimed at an appropriate
target; the boresight telescope and adapter will be installed in the
gun barrel; the boresight telescope reticle will then be focused on a
target aiming point; and, the boresight controls will be used to
align the 25mm gun reticle on the same aiming point as the boresight
The specific procedures for performing this
boresighting task are described in paragraphs 3b(1) through (25)
below. Before starting the procedure, observe these warnings:
Never look at the sun through the ISU; doing so
could cause blindness.
Accidental firing of the 25mm gun may result in
death or injury.
Make sure that the ARM-SAFE-
RESET switch is in the SAFE position. Clear and
unload the 25mm gun before boresighting.
(1) Start the engine.
(2) Drive the vehicle to within 3960 feet (1200 meters) of a
Remember that a square target is the best for
boresighting. Position the vehicle facing the target.
(3) Stop the engine.
(4) Move the TURRET POWER switch to ON.
(5) The NIGHT VISION PWR (power) switch (figure 3 on the
following page) should be turned ON now. The ISU needs ten minutes
to cool down after the NIGHT VISION PWR switch is turned ON.
Therefore, since the night sight is to be boresighted to the day
sight (in a later task), the NIGHT VISION PWR switch is turned ON at