EXTRACT
FIELD MANUAL 13-69
WAC, U.S., M1(M1A1)
1. The WAC, U.S., M1 and M1A1 was designed as an auxiliary
component to the BLANKET, Olive Drab shade 36. The WAC is a
breech-loaded, recoil operated, air cooled, pelvic action, ground
environment weapon. It may be put into action at any time and from
any position or elevation.
DESCRIPTION
2. The weapon has an average overall length of approximately 66
inches, while the circumference will vary with age and usage fac-
tors. The weapon is equipped with SHOCK ABSORBERS, two (2) each,
mounted approximately twelve (12) inches below the weapons sight-
ing devices. Size and resiliency of the shock absorbing devices
likewise varies depending on age of equipment and general condi-
tion of the weapon. The shock absorbers may be used as hand
grips during firing operations. The weapon's principle com-
ponent, the breech, will be discussed in a subsequent section.
NOMENCLATURE & FUNCTION OF THE BREECH
3. PRINCIPLE COMPONENTS: The breech of this weapon consists of
three (3) components. The first, COVER, Fur is not essential to
firing. However, the Cover, Fur is provided as standard equip-
ment on all models. The second major component is the LIP,
Breech, Flexible, two (2) each. During firing, these components
insure a snug fit for the projectile and it casing. Similarly,
it prevents the entry of dirt or other foreign objects into the
breech when the weapon is not in use. The third, and most impor-
tant component is the BREECH, which is designed to accommodate a
projectile of 38mm (approximately 1.5 inches). Certain models,
depending on age and frequency of usage, may require a slightly
larger cartridge. (NOTE: Using personnel are urged to request
armament technicians to ascertain precise bore size through pull-
over gage measurements). The length of the projectile is not of
special significance other than increasing the efficiency of the
weapon.
a. The Breech is equipped with a factory-assembled and
sealed SYSTEM, Internal Lubrication. This subsystem prevents
hangfires during operation of the weapon.
b. All newly assembled being brought into the service in-
ventory are delivered with a tough protective coating which is
located between the Breech and the Lips, Breech, Flexible. This
coating can effectively removed by simply loading and firing a
projectile. Unusual noises accompanying this procedure need not
alarm the firing personnel as they will soon subside with
repeated firings.
LOADING AND OPERATION
4. GENERAL. The weapon is most efficiently fired by a one-man
crew. However, it is quite common for the gunner to become
fatigued while operating the weapon and it may be desirable to
employ a multiple gunner crew in rotating shifts. (CAUTION: Per-
mit no more than five men to operate the weapon in a single
firing to avoid undue and dangerous stress on the weapon).
Failure to observe the above listed caution normally results in
extended non-operational time while maintenance personnel rebore
and refinish the weapon.
a. LOADING AND GUN DRILL: The gunner's primary firing posi-
tion is between the mobility devices of the weapon. Mobility
devices should be flexed at the main joints and spread to an
angle of 45 to 60 degrees to ensure minimum recoil effects. At
the count of "one", the gunner assumes the kneeling position,
projectile in the right hand and aligned with the breech. His
FINGERS, Hand, Left, are extended forward and downward to main-
tain balance. On the count "two", the HAND, Right is brought
smartly away from the projectile (which at this time should be
secured between the Lips, Breech, Flexible).
b. FIRING: To fire the weapon, the command "READY, WIGGLE"
is given. On this command of execution, the gunner briskly slides
the projectile fully into the breech and immediately commences a
gradual rocking motion with regular or intermittent lateral mo-
tion (optional) until the projectile detonates.
(1) Special care must be taken to make certain that
fusing is not set for point detonation as such a condition in-
variably results in a misfire.
(2) Qualified and proficient gunners are authorized to
employ variations to the primary firing position outlined above
in para 4.b. A unique feature of the weapon is the fact that it
operates equally well in both indoor and outdoor environments in
an almost infinite variety of firing positions. (NOTE: the
weapon is somewhat less efficient when operated in a totally ver-
tical attitude)
(3) The spent cartridge is withdrawn while the weapon
is allowed to cool and a new, fresh cartridge is prepared for
firing.
STOPPAGES
5. Once the weapon has been sufficiently and properly broken in,
stoppages rarely if ever occur. In rare cases, however, the gun-
ner may find it difficult to insert the projectile into the
Breech. The immediate field action expedient to correct this
condition calls for the gunner to manually operate manipulate the
breech assembly (i.e. Cover, Fur; Lip, Breech, Flexible; and
Breech) which should activate the System, Internal Lubrication
(para 3.a.). In extremely rare cases, use of JELLY, Lubricating,
Type K-Y is authorized and encouraged at the discretion of the
operating gunner.
MAINTENANCE
6. CARE AND CLEANING. A significant design feature on all
models of the weapon is the minimal crew maintenance necessary to
keep the weapon in Equipment Serviceability Criteria (ESC) GREEN.
a. All weapons come equipped with an internally-activated
MECHANISM, Adjustment and Purging, which like the SYSTEM, Inter-
nal, Lubrication, is installed and sealed at the point of as-
sembly. This mechanism functions normally for a period of three
to five days during each operational cycle of twenty-eight days.
Normal functioning of the mechanism during these brief periods
seriously impairs the weapon's functionality and results in an
ESC rating of RED. Gunners are warned to operate the weapon only
at their own risk during these normally non-operational periods.
SAFETY PRECAUTIONS
7. ABNORMAL CORROSION. Gunners may occasionally discover that
the breech and chamber of selected weapons produce a highly cor-
rosive effect on the projectiles and cartridges. This is par-
ticularly likely to occur in using units who fail to maintain
complete and accurate Weapon Records Data (Form 2408-4a). Where
corrosion is observed, gunners are required to make maximum use
of COVERINGS, Latex, Form-fitting, for their projectiles. The
Covering, a one-time use, expendable device must be locally
procured.
8. ABNORMAL BREECH EXPANSION. A swelling condition immediately
above the breech assembly is a critical safety hazard. Such ex-
pansion is invariably preceded by a repeated failure of the
Mechanism, Adjusting and Purging, to activate during successive
operational cycles. While failure of the Mechanism, Adjusting
and Purging, to activate and functions in itself only a short-
coming, such failure, when coupled with the swelling and expan-
sion described previously, definitely constitutes a deficiency.
In such cases, maintenance personnel should place the weapon in a
limited operational status until such time as the weapon returns
to a fully operational status. The gunner who has been deter-
mined to, or who is suspect of being responsible for creating the
subject safety hazard is advised to immediately put as much dis-
tance between himself and the weapon as current transfer regula-
tions permit.
THIS MANUAL IS A CHANGE TO PREVIOUS EDITIONS WHICH MAY BE USED
UNTIL RESCINDED BY COMPETENT AUTHORITY.
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