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 270 of 775

TM 9--2350--311--10

2--172

Change 6

2--12 PREPARATION FOR FIRING — CONTINUED

2--12.2

Boresighting — Continued

b. Test Target Method

WARNING

The test target method of boresighting must be used to check M140/M140A1 alinement device.

Failure of M140/M140A1 alinement device reticle to aline with reticles of M117/M117A2

panoramic telescope and M118A2/M118A3 elbow telescope could result in projectiles landing

outside target area. Injury or death of friendly forces can result from firing with misalined fire

control equipment.

1

Perform all preliminary procedures (para 2--12.2a.).

2

Prepare test target (13) as follows:

(a) Fasten test target (13) to a stand (14) for stability.

(b) Prior to boresighting in dark, drill a 1/16 inch (1.59 mm) hole through center of each aiming

diagram (15). Cover holes with a piece of cloth. At night, hold a flashlight to the boresight, against

the cloth.

NOTE

Measurements do not appear on test target. They are shown in case it is necessary to make a

test target.

3

Locate test target (13) 55 yards (50 m) in front of howitzer.

4

Without moving cannon tube, aline center of aiming diagram (15) with muzzle crosshairs (3).