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 Change 3 3–71 3–6 ARMAMENT AND CAB MAINTENANCE — CONTINUED 3–6.8 Breech Mechanism — Continued c. Assembly WARNING The breechblock weighs approximately 125 pounds (57 kg). It takes two personnel to install the breechblock to prevent injury to personnel. 1 Slightly raise operating cam (12) enough to clear rollers (11) from operating cam path. Rotate operating crank assembly (71) to move gear rack and sector gear timing marks (72) to the center of the inspection hole (73) in the carrier assembly (39). Scribe a line (73.1) from gear rack timing mark (73.2) onto carrier assembly (39), insure line extends completely down and onto outer edge of carrier assembly. Slowly lower operating cam to rest on rollers. 1.1 Scribe a line (73.3) from timing mark (73.4) onto breechblock (9), insure line extends completely down and onto outer edge of breechblock. 12 11 71 72 73 39 73.2 73.1 39 73.3 9 73.4