Table 13-1.--Malfunctions or Stoppages, Their Causes, and Corrective Action
Malfunction
Probable cause
Corrective
Malfunction
Probable cause
Corrective
or stoppage
action
or stoppage
action
Failure to feed.
Gas pressure
Ammunition
insufficient . . . . . . . . . . . . .Clean gas port.
faulty . . . . . . . . . .Replace
Feed pawl or feed
ammunition.
pawl spring
Chamber dirty. . .Clean or change
defective . . . . . . . . . . . . . . .Return to
barrel.
Armorer.
Operating rod
From. and rear
drive spring
cartridge guides
weakened or
defective. . . . . . . . . . . . . .Return to
damaged . . . . . . .Armorer
Armorer.
replaces spring.
Cover latch
Failure to extract.
Extractor or
defective. . . . . . . . . . . . . . . Return to
spring broken Armorer
Armorer.
replaces spring.
Feed lever
Short recoil . . . . . . Clean gas port,
cam spring
operating rod
defective . . . . . . . . . . . . . . .Return to
tube, and
Armorer.
lubricate.
Cam roller
Gas piston
defective . . . . . . . . . . . . . . .Return to
installed
Armorer.
backwards. . . . . Install
Lubrication
properly.
Short recoil . . . . . .Clean gas port.
inadequate . . . . . . . . . . . . . Apply lubricant.
Failure to eject.
Ammunition or
Ejector or
link defective . . . . . . . . . . Insert new
ejector spring
ammunition
frozen or
or link.
damaged . . . . . . .Clean or armorer
Ammunition belt
replaces port.
installed wrong. . . . . . . . . . Reverse belt
Failure to cock.
Sear broken . . . . . .Return to
with open
armorer.
portion of
Operating rod
link down.
sear notch
Operating rod
worn . . . . . . . . .Return to
spring damaged
Armorer
armorer.
or weakened . . . . . . . . . . . . . replaces spring.
Sear plunger or
Obstruction in
spring broken
receiver . . . . . . . . . . . . . . . Remove
or defective. . . . . Return to
obstruction.
armorer.
Failure to chamber. Ruptured cart-
Obstruction in
ridge case . . . . . . . . . . . . . . Remove cart-
receiver . . . . . . . .Clear as
ridge case.
required.
Caked carbon in
Short recoil
Clean gas port.
gas cylinder . . . . . . . . . . . . .Remove carbon.
Runaway gun.
Sear broken or
Caked carbon
worn. . . . . . . . . . .Return to
receiver . . . . . . . . . . . . . . . .Remove carbon.
armorer.
Round damaged . . . . . . . . . . . Remove round.
Sear notch on
Failure to fire.
Firing pin
operating rod
damaged or
worn. . . . . . . . . . Return to
broken. . . . . . . . . . . . . . . . .Armorer replaces
armorer.
firing pin.
Sluggish operation.
Excessive
Firing pin spring
friction. . . . . . . . Clean and
damaged
lubricate.
or broken . . . . . . . . . . . . . .Armorer
Excessive loss
replaces spring.
of gas. . . . . . . . .Tighten or
replace gas
port plug.
13-11
