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 341 of 775
TM 9-2350-311-10
2-15 MISFIRE PROCEDURES — CONTINUED
2-15.2
Preventive and Corrective Measures When Howitzer Fails to Fire — Continued
b.
Charge 2 Misfire in a Hot Cannon Tube
1
2
3
4
5
6
If weapon fails to fire after one attempt, immediately attempt to refire two more times.
•
Primer removal may expose cannoneer to danger of a recoiling weapon if a hangfire exists.
•
If a commander, in order to avoid prolonged loss of weapon, determines to fire projectile, it
must be fired within 5 minutes of projectile cambering.
•
Stickers may infrequently occur when firing charge 2. When stickers occur, projectile lodges
in cannon tube and hot gases under pressure are trapped in primer chamber. Removal of
primer is dangerous, as it will be expelled rearward when released. Expelled primer may
cause injury to personnel standing in path of ricochet.
●
Stand clear of recoiling parts, exposing only hand and arm when removing primer before
end of safe wait period.
•
Do not grasp the lock pin, so that hand is exposed to being hit by expelled primer.
If weapon fails to fire, wait 2 minutes after last firing attempt.
Evacuate extra personnel to a safe distance, open hull rear door, and position cannon tube so primer
can be expelled through open hull rear door, should there be a sticker.
Stand to right side of breech, Grab follower assembly knob and pull outward, until it is free to be opened.
Keeping follower assembly knob out, firmly slide block assembly toward the open position until primer
pops and gases are vented or primer is ejected normally.
If sticker occurs, personnel should evacuate vehicle through cab side doors, gunner’s escape
hatch, or commander’s cupola and notify EOD. Exiting through rear doors could cause injury.
Inspect primer if no pop-out occurs.
If primer has fired, a hangfire condition continues so failure to observe hangfire procedures
could cause injury to personnel and damage to equipment.
Immediately insert a new primer and refire.
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