SECTION III CARE AND CLEANING • 7. CLEANING.

• A. Bore, chamber, and breech ring.—Ordi nary cleaning after firing using waste or rags includes the fol lowing procedure. Remove breechblock. Thoroughly sluice and sponge bore and chamber with either hot water and issue soap, sal soda solution, hot water alone, or in the absence of these with cold water. Then with dry waste or rags swab bore and chamber until they are perfectly dry and clean. Finally oil parts lightly, making certain that the oil covers all surface of the bore. This cleaning should be done as soon as practicable after firing. If the gun is not to be fired for several days a daily inspection should be made to determine whether further cleaning is necessary. The interior of the breech ring should be cleaned and then wiped with an oily rag. If the gun is to be stored for an appreciable period a heavy grease, such as rust-preventive compound (U. S. Army Spec. No. 2-82B), should be applied as a preservative. 
• B. Breechblock.—Remove breechblock from breech ring and disassemble it. With a dry rag clean dirt and oil from the block and all parts contained therein. Using light oil, lubri-cate recesses for firing pin, rocker, and rocker plunger. With an oily rag wipe the breechblock, leaving a thin coating of oil, especially on threads and face of the block. 
• C. Extractor and sear.—Remove extractor and sear from the gun, and clean and oil by wiping thoroughly, first with a dry and then with an oily rag. Oil recesses for the extractor pin and sear plunger before replacing these parts. 
• D. Outer surfaces of gun.—Clean the outer surfaces, then dry and wipe all exposed metal parts with a lightly oiled rag. Oil interior of the striker housing. Place a drop of oil in recesses for the striker and the safety bolt. 
• E. Tripod.—Clean outer surfaces, including mortises of axle stay clamps and the holes through which the traversing screw passes. Oil lightly trunnion bearings, pintle bushing, socket, stud, bearings of traversing screw, traversing screw, travers ing screw plunger, elevating screw latch housing, elevating screw nut, and elevating screw. 
• F. Axle and wheels.—Using a sponge, wash with water to remove dirt and other fouling that gathers during trans portation. Oil pintle socket bearing lightly. Grease axle spindles at intervals to suit circumstances, insuring that they are properly lubricated at all times.
•  G. Guides, jacket shoe, and clip shoe.—Remove barrel from cradle. With a cloth wet with dry-cleaning solvent, clean inner surfaces of guides and outer surfaces of shoes, then dry the parts. Grease liberally with a heavy oil and reas semble. This will be necessary only in sandy country or under other unusual circumstances. 
•  8. SPECIAL PRECAUTIONS DURING UNUSUAL CONDITIONS.—a. Cold weather.—The gun should be tested frequently by hand manipulation to insure that it is functioning properly. b. Gas attack.—lids on ammunition chests should be closed and if practicable a heavy coating of thick oil applied to the bore and working parts of the gun. Directly after gas at tack the gun should be thoroughly cleaned, using hot water containing a little soda if obtainable. Ammunition should be wiped with an oily rag and fired as soon as tactical condi tions permit. Ammunition that has been subjected to gas action should be inspected very carefully and thoroughly before firing.
•  9. PILLING RECOIL CYLINDER OF CRADLE.—a. The recoil cyl inder has a capacity of about 2.75 pints of oil. It must be kept properly rilled in accordance with the following in structions, or damage to the gun will probably result. The Ordnance Department will furnish the proper grade of oil for recoil cylinders. The following specification is used: Oil, recoil, heavy, U. S. Army Spec. No. 2-36C. The substitu tion of any filler other than that issued by the Ordnance Department is prohibited. 6. To fill the recoil cylinder, proceed as follows: (1) By means of the elevating screw depress the muzzle as far as possible. (2) Fill oil gun with oil. (Unscrew cap with muzzle at tached, draw piston back to its full extent, fill cylinder, screw on cap with nozzle attached, and with nozzle pointing up ward push in piston until oil starts to flow in order to force the air out of the oil gun.) (3) Unscrew filling plug in front end cap of recoil cylinder and screw nozzle end of oil gun into position in its stead. (4) Unscrew drain plug. (5) Introduce oil into recoil cylinder by slowly pushing in piston of the oil gun, and continue until the oil escaping through the drain hole (from which the drain plug was removed) no longer carries air bubbles. (6) Holding a finger over the overflow hole to prevent rapid escape of oil, unscrew oil gun, and allow about 1 spoonful (spoon issued with mess equipment) of oil to escape. (7) Screw both plugs tightly in place. • 
• 10. PRACTICES To BE AVOIDED IN USE AND OPERATION OF GUN.— a. Snapping trigger mechanism when chamber is empty. b. Pressing trigger crank lever, the breech not being com pletely closed. c. Rotating or attempting to rotate breechblock, gun being uncocked. d. Putting a strain on the shoulder guard, either in carry ing the gun or by leaning on it while getting into or out of gunner's position on left trail. e. Putting a strain on elevating handwheel by allowing rear end of cradle to drop, or to rest on it when elevating screw is unlatched from elevating screw latch catch bracket in removing the gun from the mount. The material of which the handwheel is made is quite brittle and will not stand rough handling.