TM-9-2350-311-10

TM 9-2350-311-10

3-7 FIRE CONTROL ALINEMENT TESTS AND

3-7.8

Testing and Scribing M15 Elevation Quadrant

a. Testing

NOTE

MEASUREMENTS — CONTINUED

• If M15 elevation quadrant is already scribed, proceed to field verification of scribe lines

(para 3-7.11).

• The M15 elevation quadrant is scribed so that the crew may accurately level the gun

trunnions without using the plumbline.

Level the gun trunnions (para 3-7.3).

Turn the elevation knob (1) to place the elevation counter (2) on zero.

Turn the correction knob (3) to place the correction counters (4) on zero.

Turn the cross-level knob (5) to center cross-level (6) bubble.

Manually elevate or depress the cannon tube until the elevation level (7) bubble centers and the cannon

tube is at zero elevation. The elevation counter (2) and the correction counters (4) should still read zero.

Relevel cross level (6) if necessary.

Set the elevation counter (2) to 600 mils while watching the cross-level (6) bubble and slowly elevate the

cannon tube to 600 mils. During elevation movement, the bubble must not move over 2 graduation

marks from the center of the cross-level, If it does, the M15 elevation quadrant (8) may be defective;

notify unit maintenance.

Set the elevation counter (2) to zero mils and depress the cannon tube to zero mils. Again observe the

cross-level (6) bubble. It must not move over 2 graduation marks on the cross-level.

When the cannon tube is at zero elevation, carefully recenter the cross-level (6) bubble, if necessary.

If bubble in cross-level (6) does not center, repeat steps 4 through 8. If it still does not center, notify unit

maintenance.

3-104

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