TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
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3-7 FIRE CONTROL ALINEMENT TESTS AND 3-7.3 Leveling Gun Trunnions — Continued a. Plumbline Method — Continued 3 Suspend plumbline (4) with weight (5) attached at a TM 9-2350-311-10 MEASUREMENTS — CONTINUED location where there is little or no wind. The plumbline must be high enough (22 feet (6.7 m)) to elevate cannon tube (6) to 600 mils. 4 Place weight (5) in waste oil or water. 5 Position weapon so that cannon tube (6) is within 12 inches (30.48 cm) of the plumbline (4). NOTE Use jacks with capacity of 10 tons or better. Ensure hydraulic jacks do not leak so test will be accurate. NOTE An alternate method to steps 6 and 7 is to place one jack under center front of vehicle and two jacks under left and right rear sides of vehicle. 6 Install two jacks (7) on the left and right front sides under 1 inch (2.54 cm) pads (8). Raise jacks until they support a load. 3-87