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.