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 496 of 775

TM 9-2350-311-10

3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED

3-7.3

Leveling Gun Trunnions — Continued

b. Scribed Lines Method

1

2

3

4

NOTE

This procedure applies only to weapons with M15 elevation quadrants that have been previously

scribed (para 3-7.8).

Position the weapon on as firm and level ground as is possible or hardstand if one is available.

Turn on M15 elevation quadrant (12) lights with toggle switch (13) and carefully aline scribe lines (16)

and (17).

Set zero mils on M15 elevation quadrant (12) and level the elevation bubble (15) by elevating or

depressing the cannon tube (6).

Manually and slowly traverse the cannon tube (6) (either direction) while someone watches the

cross-level bubble (18). Stop traversing when the cross-level bubble centers. Manually elevate or

depress the cannon tube until the elevation bubble (15) centers. Recheck the cross level bubble. If

cross-level bubble remained exactly centered, the gun trunnions are level. If not, traverse until the

cross-level bubble is centered. The gun trunnions are now level.

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