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 298 of 775

TM 9-2350-311-10

2-12 PREPARATION FOR FIRING — CONTINUED

2-12.4

Pre-Fire Checks — Continued

b. Cannon Tube

1

Cannon tube (7) must be dry and clear with no visible damage or foreign matter present.

•

If cannon is new or retubed, check the following before initial firing. If either step 2 or step 3 is

not right, do not fire. The cannon may blow up, causing severe injury or death to personnel.

Notify unit maintenance.

•

If major work has been done by direct support or general support maintenance, fire first

round using 50 foot lanyard to prevent injury.

•

Do not fire without follower assembly. This will result in injury to personnel and damage to

equipment.

•

High intensity hearing protection is required. Decibel levels from firing exceed safe levels for

human hearing. Failure to wear hearing protection could result in hearing impairment.

•

The ventilation blower VENTILATOR BLOWER INTAKE switch must be turned to INTAKE

during firing (para 2-17.3).

CAUTION

After a new M284 cannon assembly or a new torque key has been installed, a zone 6 charge

must be fired to mate the torque key and the cannon tube. Failure to follow this procedure could

result in equipment damage.

2

Rear face of cannon tube (7) must be flush with forward shoulder of breech ring (8).

3

Measure distance from rear face of cannon tube (7) to rear of breech ring (8). Distance cannot be more

than five inches (12.7 cm).

2-200