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 291 of 775

TM 9-2350-311-10

2-12 PREPARATION FOR FIRING — CONTINUED

2-12.3 Standard Angle Method

a. Determining the Standard Angle

NOTE

When performing fire control alinement tests and measurements, ensure the gun trunnions are

leveled using the plumbline method (para 3-7.3) and that the M1451M145A1 telescope mount is

scribed (para 3-7.9).

1

Perform fire control alinement tests and measurements (para 3-7).

2

Inspect recuperator assembly pins (1) to ensure that the recoil system contains the proper amount of

hydraulic fluid (item 12, Appx G).

NOTE

The scribe line at the junction of the variable recoil cylinder and the machine bushing verifies that

the recoiling and non-recoiling parts of the howitzer have the same relationship as when the

standard angle was determined during fire control alinement tests.

3

Scribe a line at the junction of the variable recoil cylinder (2) and the machine bushing (3).

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