SECTION V DEFECTS AND STOPPAGES

• 17. DEFECTS AND STOPPAGES.—Defects and stoppages do not occur with sufficient frequency to warrant a special form of drill in remedying them. They are listed herein for informa tion. Such instruction will be given the soldier in their nature and the action necessary to remedy them as will insure the most efficient operation of the gun. 
• (A). When breech cannot be opened and inspection discloses that gun is not cocked.— (1) Causes.— (a) Failure to release pressure on trigger crank lever when the gun fires. 
• (B) Worn or broken sear, or weak sear spring. (2) Action to remedy.—Cock the gun. Caution firer to re lease pressure on trigger crank lever when the gun fires. If the gun will not cock, replace defective part. 
• b. When breech cannot be opened and inspection discloses that gun is cocked.— (1) Causes.— (a) Firing pin is engaged . in primer because of a weak or broken firing-pin spring or burred or dirty rocker mechanism. (&) Piston cross head key has not been inserted fully with the result that the safety bolt is not withdrawn from notch in breechblock cap.
• (2) Action to remedy.— (a) Withdraw safety bolt from notch in breechblock cap and insert piston cross head key properly. (b) Tap with some soft object on the protruding part of rocker and work breechblock lever until firing pin comes loose. This failing, insert rammer into bore from muzzle and tap empty cartridge case. If this is not effective, remove rocker and attempt to withdraw firing pin. As a last resort, break off firing pin by forcing the breech open, replace defective parts, and clean and oil rocker mechanism. If the rocker mechanism is burred, smooth carefully with a fine file or emery paper. c. When gun fails to eject empty cartridge case.— (1) Causes.— (a) Failure to open breech smartly. (b) Defective ammunition. (c) Broken or worn extractor. (d) Dirty chamber. (2) Action to remedy.— (a) Close breech and open smartly. (b) If this is not effective, remove the empty case with the rammer by inserting the rammer through the bore from the muzzle; the hand extractor also may be used to remove rounds or empty cartridge cases from the chamber. (c) Replace extractor if necessary. (d) Clean chamber thoroughly. d. When gun fails to return completely into battery.— (i) Causes.— (a) Dirty or burred slides or shoes; lack of grease on slides for shoes. (b) Expansion of oil in recoil cylinder because of over heating. (c) Weak counterrecoil springs. (2) Action to remedy.— (a) If necessary to continue firing, push the gun forward into battery by hand. When necessity for fire ceases, clean and grease shoes and slides. If burred, smooth them carefully with a fine file or emery paper. (b) If shoes or slides are not dirty or burred, unscrew fill ing plug and allow about a spoonful (spoon issued with mess equipment) of oil to escape. (c) Should the above remedies be ineffective, the gun should be returned to the Ordnance Department for repair.