FM 23-45 Basic Field Manual
3
F
IGURE 2.—Rear sight.
This elevating screw mechanism is equipped with a mil click device which may be used
in conjunction with a mil scale engraved on the left side of the rear sight leaf to
measure or establish angles of elevation in mils.
(3) The windage screw mechanism also incorporates a mil click device. Adjustment
of the rear sight leaf in windage is accomplished by rotation of the windage screw knob.
Amount of motion permitted is 10 mils right or left from zero.
(4) The sight radius is 13.94 inches.
■7. PINTLE. — The pintle of the light machine gun (ground), although technically not
a part of the gun, is permanently assembled thereto by a bolt through the trunnions of
the pintle and the trunnion hole of the receiver of the gun. Failure to keep this bolt
tight will result in inaccuracy of fire. This pintle is tapered and mates with the
corresponding tapered pintle bushing of the tripod mount M2 head. This tapered pintle
thus serves as a tight wearing union between the receiver of the gun and its mounting.
The pintle is secured in its mounting by the engagement of a spring actuated pintle
latch of the mounting in a corresponding annular groove of the pintle.
■8. ELEVATING AND TRAVERSING MECHANISM.
a
. As with the pintle, the elevating and traversing mechanism is not technically a
part of the gun. However, the elevating and traversing mechanism is permanently
secured to the receiver of the gun by a bolt through the head of this mechanism and the
elevating bracket of the gun. In guns of new manufacture, the elevating bracket is
integral with the bottom plate.
b
. The elevating and traversing mechanism, when used with the tripod M2, consists
of an upper elevating screw; a lower elevating screw; an elevating handwheel assembly
secured to the head of the lower elevating screw; a housing mating with the lower
elevating screw; a traversing block mounted by a swivel joint to the lower elevating
screw housing.
(1) The upper elevating screw terminates at its upper end in an offset head which
incorporates a recess for the bolt which assembles the entire elevating and traversing
mechanism to the gun. The mechanism is properly assembled to the gun when the
offset head points to the rear, thus permitting the mechanism to be folded to the rear
and seated in its recess in the duralumin grip. The inner elevating screw is externally
threaded to mate with the internal threads of the lower elevating screw. It is equipped
