Figure 14-5.--Sight unit (M64/M64A1).
telescope mount and a nonmaintainable elbow
telescope, fastened into one unit for operation. The
elbow telescope provides magnification and a line of
Figure 14-6.--Boresight (M115).
sight from which the mortar is aimed. The elbow
telescope is a 1.5-power, fixed-focus telescope. The
deflection knob during firing. The coarse deflection
cross lines are at right angles to each other.
scale is fixed to the upper parts of the center section and
The TELESCOPE MOUNT consists of the lower,
has 64 graduations. This scale rotates with the upper part
center, and upper parts. The lower part contains a
of the telescope mount. The coarse deflection slip scale
locking lever latch, an elevation micrometer knob with
is located adjacent to the coarse deflection scale. The
scale, and an elevation locking knob. There is also a
dovetail bracket located on the right side of the mount
graduations, numbered from 0 to 100 in increments of
that mates with the dovetail slot located on the yoke of
1 mil. The M225 cannon, the M8 baseplate, and a heat
the biped. A semicircular, coarse elevation scale
protective mitten are all that is required to use this
indicates from 700 to 1,600 mils in 100-mil increments.
weapon in the hand-held mode.
The ELEVATION KNOB contains an elevation
The BORESIGHT (Ml15) (fig. 14-6) is used to
micrometer scale of 100 mils, numbered in l-mil
calibrate the sight for the mortar. Since no two mortars
are exactly alike, each sight MUST be calibrated on its
increments from 0 to 100. Turning the elevation knob
tilts the mount in elevation to the desired angle, as read
own mortar. The body of the boresight contains three
level vials. They are used to determine that the angle of
on the coarse and micrometer elevation scales. The
elevation (preset at 800 mils) and to determine that the
elevation locking knob prevents the elevation knob from
V-slides are in a perpendicular position.
rotating during firing.
THE AIMING POST (M1A2) is used with the
The center part of the telescope mount has a
mortar as an aiming point. Two aiming posts are
deflection knob that rotates the mount for direction. A
provided for each mortar. These aiming posts can be
crank is provided on the knob for rapid deflection
separated in the center so as to be more compact when
movement. The deflection locking knob locks the