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 491 of 775

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