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 6 2--181 2--12 PREPARATION FOR FIRING — CONTINUED 2--12.2 Boresighting — Continued d. Checking Boresight of M117/M117A2 Panoramic Telescope Using the M140/M140A1 Alinement Device — Continued WARNING The breechblock must be opened and the operating handle left unlocked. To prevent injury to personnel, be careful not to lift up on operating cam before securing operating handle after leveling cannon tube. 4 Unlatch operating handle (33) enough to place M1A1 gunner’s quadrant (5). 5 Depress or elevate cannon tube to 0 mils using M1A1 gunner’s quadrant (5) on elevation seats (8) of breech. Make sure cannon tube and M1A1 gunner’s quadrant corrections are added when depressing or elevating cannon tube (para 3--7.5). 6 Aline scribed lines on cross-level mechanism knob (34) and pitch level knob (35) of M145/M145A1 telescope mount (12) (para 3--7.7). 34 35 12 8 5 33