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 293 of 775

TM 9-2350-311-10

2-12 PREPARATION FOR FIRING — CONTINUED

2-12.3

Standard Angle Method — Continued

a.

Determining the Standard Angle — Continued

7

Boresight using the test target method (para 2-12.2).

NOTE

•

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

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

of tape.

•

Final movement of the azimuth knob when making any setting should be in a clockwise

direction.

8

Using a parallax shield, turn the M117/M117A2 panoramic telescope (11) azimuth knob (12) to aline the

vertical hairline (13) of the M117/M117A2 panoramic telescope on the farthest, left edge of the muzzle

brake (4). Aline the horizontal hairline (14) of the M117/M117A2 panoramic telescope on the top edge of

the muzzle brake by turning the elevation knob (15).

9

Record the reading from the Ml 17/M117A2 panoramic telescope (11) azimuth counter (16) to the

nearest 1/4 mil. This is the standard angle of deflection for this M145/M145A1 telescope mount (6),

Ml 17/M117A2 panoramic telescope, and howitzer.

Change 2

2-195