TM-9-2350-311-10

TM 9-2350-311-10

3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED

3-7.7

Testing the M145/M145A1 Telescope Mount (Azimuth Walk-Off)

NOTE

Gun trunnions must be perfectly level before conducting the azimuth walk-off test.

Level the gun trunnions (para 3-7.3).

NOTE

If the azimuth walk-off testis being performed independently, install M117/M117A2 panoramic

telescope in M145/M145A1 telescope mount, and depress cannon tube to zero mils before

doing step 2.

Center the cross-level (1) and pitch level (2) bubbles of the M145/M145A1 telescope mount (3).

NOTE

• A parallax shield can be made to prevent movement in two ways. One is to use a dust cap

with a hole in the center. The second is to use a small opening marked off with strips of tape.

• If the reference point is less than 55 yards (50 m) away, use a parallax shield.

Turn the azimuth knob (4) to place the vertical reticle of the M117/M117A2 panoramic telescope (5) on

any stationary reference point (6), at any defIection. Be sure to approach the reference point from left to

right. Record the reading on the azimuth counter (7) to the nearest 1/4 mil.

NOTE

Be careful not to traverse the cannon tube.

Elevate the cannon tube to 400 mils. Center the cross-level (1) and pitch level (2) bubbles and turn the

azimuth knob (4) to realine the vertical reticle on the same stationary reference point (6). Make sure you

approach the reference point from left to right, The reading on the azimuth counter (7) must be within

± 1.0 mil of the reading taken in step 3. If not, notify unit maintenance.

Elevate the cannon tube to 900 mils. Center cross-level (1) and pitch level (2) bubbles and realine the

vertical reticle as in step 3 on the same stationary reference point (6). Approach the reference point from

left to right. The reading on the azimuth counter (7) must be within ± 2 mils of the reading taken in step

3. If not, notify unit maintenance.

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