188.8.131.52 Firing fixture. Machine guns shall be tested using
the test fixture conforming to drawing 7273907 and 11017785.
With the rear sight set at zero windage and the elevation scale
set so that the scale retaining screw is approximately at the
midpoint in the slot, the sight aperture slide shall be brought
to the elevation setting indicated on the targeting and accuracy
With the sights aligned at 6 o'clock on the sighting
image of the targeting and accuracy diagram, a 10-round burst
shall be fired for the targeting and accuracy measurement. The
barrel assembly with biped assembly shall be replaced by the
spare barrel assembly with biped assembly and with a 6 o'clock
hold on the sighting image of a new target, a 10-round burst
shall be fired for the targeting and accuracy requirements.
Adjustment of the sights may be made within the limitations of
184.108.40.206 to bring the two barrels within the targeting
requirements with the same sight setting. A 3-round warmup burst
is allowable when testing each barrel assembly with biped
Adjustment to the rear sight shall not
220.127.116.11 Rear sight.
cause overhanging of the rear sight base. Vertical adjustment
shall be made by movement of the adjustable elevation scale and,
after adjustment, determination shall be made that the required
Filing of the
additional adjustment is available (see 3.4.6).
top of the front sight base shall be allowed to correct for
vertical deviation provided that resulting bright areas are
covered with an approved touch-up paint or coating.
18.104.22.168 Rear sight base. Upon satisfactory completion of
the targeting and accuracy firing test, the rear sight base shall
be staked in place and the adjustable elevation scale shall be
set at the correct scale graduation.
4.5.7 Interchange of Parts
22.214.171.124 In plants
Machine guns shall be tested for
126.96.36.199.1 Machine suns.
interchange of parts (see 3.4.7) by disassembling and then
reassembling parts using the parts and prearranged system
Interchange of parts shall be
prescribed below in Table II.
accomplished by dividing the parts of each machine gun into 10
groups of nonmating parts as shown below and distributing the
groups into 10 different trays until each tray contains a
Groups of parts from machine gun number 1
complete machine gun.
shall be taken in-order and-placed in tray 1 through 10; groups
of parts from machine gun number 2 shall be taken in order and