TM-9-2350-311-10

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; OPERATOR’S MANUAL

NOVEMBER 1994

TM-9-2350-311-10 - Page 279 of 775

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