TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
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TM 9-2350-311-10 Item No. 23 Interval Before Table 2-1. PREVENTIVE MAINTENANCE CHECKS AND SERVICES FOR M109 SELF-PROPELLED HOWITZER - CONTINUED Location Item to Check/ Service Firing Mechanism, Firing Block Assembly, And Primer Chamber Crewmember Procedure CANNONEER NO. 1 a. With firing block assembly (1) in center position, push firing mechanism (2) into firing block as- sembly and rotate clockwise to remove. Remove lock pin and firing pin (3) and check to see if firing pin is damaged or broken. NOTE The M35 firing mechanism is used with the M109A2/M109A3/M109A4 M178 mount/M185 cannon assembly. The M49 firing mechanism is used with the M109A5 M182 mount/M284 cannon assembly. b. Replace firing pin (3) and firing mechanism (2). Place firing mechanism in firing position. c. Attach lanyard and check operation of firing mechanism with a steady pull on the lanyard. A click will be heard and firing mechanism (2) should recock. d. Check follower assembly (4) operation. e. Check primer chamber (5) for rust and powder fouling. f. Clean primer chamber (5) by inserting reamer assembly into primer chamber as far as it will go. Rotate briskly. g. Slide firing block assembly (1) back and forth to check for smooth movement. If firing block as- sembly binds, notify unit maintenance. Not Fully Mission Capable If: Firing mecha- nism (2) or fol- ower assembly 4) is unservice- able or missing. Firing pin (3) is damaged or bro- ken. Change 2 2-39