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 3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED 3-7.6 M117/M117A2 Panoramic Telescope Reliability Testing a. Testing Reliability of Deflections 1 2 3 4 Install M117/M117A2 panoramic telescope (1) in M145/M145A1 telescope mount (2) (para 2–11.1). Center the cross-level (3) and pitch level (4) bubbles of the M145/M145A1 telescope mount (2). Set the gunner’s aid counter (5) to 0. NOTE • To prevent eye movement, a parallax shield can be made in two ways. One is to use a dust cap with a pin hole in the center. The second way is to use a small opening marked off with strips of tape. • If reference point is less than 55 yards (50 m) away, you must use a parallax shield. Sight on a reference point (6) at least 55 yards (50 m) away. 3-99