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071-100-0004 (SL1) - Maintain an M4 or M4A1 Carbine

Created by: Team Quinstreet
Posted : Monday January 01, 1900

Standards: Cleaned, inspected, and lubricated the carbine and magazine so they functioned correctly. Cleaned and inspected the ammunition. Turned in any unserviceable ammunition.

Conditions: Given an M4 or M4A1 carbine, magazine, 5.56-mm
ammunition, and small-arms accessory case
with the following cleaning materials: clean
wiping rags, bore brush, chamber brush,
toothbrush, cleaning rod, small-arms swabs,
pipe cleaners, cleaner lubricant and
preservative (CLP), lubricating oil arctic
weather (LAW), and carbine bore cleaner.

Standards:
Cleaned, inspected, and lubricated the
carbine and magazine so they functioned
correctly. Cleaned and inspected the
ammunition.  Turned in any unserviceable ammunition.

Performance Steps

1.   Clear the carbine.

a.
Remove the magazine from
the carbine, if there is one present.

b.
Cock the carbine.

c.
Turn the selector to SAFE.

Note. The selector cannot be turned to SAFE unless the carbine
is cocked.

d.
Lock the bolt open.

(1) 
Pull the charging handle
rearward.

(2) 
Press the bottom of the
bolt catch.

(3) 
Allow the bolt to move
forward until it engages the bolt
catch.

(4) 
Return the charging handle
to the forward position.

(5) 
Ensure the selector is on
SAFE.

e.
Check the receiver and
chamber to ensure they do not contain
ammunition.

2.   Disassemble the carbine.

CAUTION:
Do not use a
screwdriver or any other tool when
removing the handguards. Doing so
may damage the handguards, slip
ring, or both.

WARNING:
Use care not
to bend or dent the gas tube while
removing handguards

a.
Remove the sling.

b.
Remove the handguards if
you can see dirt or corrosion through
the vent holes. Handguards are
interchangeable because they are
identical.

CAUTION:
Use only hand
pressure to disengage the pivot and
takedown pins. Force other than hand
pressure may cause damage to the
weapon so replacement of the weapon
is required. Push the pivot and
takedown pins only far enough to
disengage the upper receiver from
the lower receiver.

c.
Push the takedown pin as
far as it will go and pivot the upper
receiver from the lower receiver.

d.
Push the receiver pivot
pin.

e.
Separate the upper and
lower receivers.

f. 
Pull back the charging
handle.

g.
Remove the bolt carrier and
bolt.

h.
Remove the charging handle.

CAUTION:
Do not fully
remove the round nuts from the
threaded studs. The threaded studs
are flared on the end to prohibit
removal. However, if the nuts are
inadvertently removed, they may be
reinstalled.

i.  
Remove carrying handle
assembly. Loosen the round nuts on the
left side of the carrying handle
approximately four turns. Loosen the
clamping bar from the left side of the
upper receiver and lift off the
carrying handle.

j.  
Remove the firing pin
retaining pin.

k.
Put the bolt assembly in
the locked position by pushing in the
bolt.

l.  
Remove the firing pin by
allowing it to drop out of the rear of
the bolt carrier into your hand.

m.  
Remove the bolt cam pin by
turning it one-quarter turn and
lifting it out.

n.
Pull the bolt assembly from
the carrier.

Note. Perform steps o through q only when the parts are dirty
or damaged.

o.
Press the rear of the
extractor pin to check spring
function. Report any weak springs to
unit armorer for replacement.

p.
Remove the extractor pin by
pushing it out with the firing pin
(use care not to damage the firing
pin).

q.
Lift out the extractor and
spring, taking care that the spring
does not separate from the extractor.

r. 
Release the buffer by
pressing the buffer and depressing the
retainer.

s.
Remove the buffer and
action spring separating the buffer
from the spring.

t. 
Extend the buttstock
assembly to full open. The M4/M4A1 has
a four-position buttstock: closed, 1/2
open, 3/4 open, and full open.

u.
Grasp the lock lever in the
area of the retaining nut, pull
downward, and slide the buttstock to
the rear to separate the buttstock
assembly from the lower receiver
extension.

3.   Clean the carbine.

a.
Upper receiver group.

(1) 
Use small-arms swabs, CLP,
and bore brush to clean bore.

(2) 
Use rags, cleaning brush,
and CLP to remove powder fouling,
corrosion, dirt, and rust from other
areas.

(3) 
Clean bolt lugs with CLP
and chamber brush.

(4) 
Use CLP and bore brush to
clean barrel locking lugs and gas
tube.

b.
Lower receiver group.

(1) 
Remove powder fouling,
corrosion, and dirt with rags,
cleaning brush, and CLP.

(2) 
Clean buffer tube and
buttstock tube with rag attached to
holder.

(3) 
Clean buffer action spring
and inside lower receiver extension
with brush and rags.

c.
Bolt carrier group.

(1) 
Clean outer and inner
surfaces of bolt carrier with rags and
CLP.

(2) 
Clean carrier key (use worn
bore brush).

(3) 
Clean firing pin recess and
firing pin with brush and CLP.

(4) 
Clean firing pin hole with
pipe cleaner and CLP.

(5) 
Clean carbon deposits and
dirt from locking lugs with cleaning
brush and CLP.

(6) 
Clean areas behind bolt
ring and under lip of extractor with
brush and CLP.

4.   Inspect carbine for serviceability.

a.
Upper receiver group.

(1) 
Check for free movement of
the forward assist assembly.

(2) 
Check for broken or damaged
ejection port cover.

(3) 
Check rear sight windage
and elevation knob for damage and
looseness.

(4) 
Check carrying handle
assembly for missing or damaged parts
and ensure the handle assembly will
mount to the upper receiver.

(5) 
Check front sight assembly
for damage.

(6) 
Inspect bore and chamber
for pitting or obstructions.

(7) 
Inspect bolt lugs for
cracks and burrs.

(8) 
Check for free movement of
slip ring.

(9) 
Check the compensator for
proper alignment.

Note. The compensator has five slots. The third or middle slot
should line up with the front sight
post. If not, turn the compensator in
for maintenance.

(10)
Check the bolt guide rails for
chips and burrs.

b.
Lower receiver.

(1) 
Check trigger mechanism for
missing or damaged parts.

(2) 
Check bolt catch for free
movement.

(3) 
Check magazine release
button for free movement.

(4) 
Check buttstock assembly
for dents and rust and ensure proper
operation of retaining nut and
lock-release lever.

(5) 
Check action spring and
buffer for damage.

c.
Bolt carrier group.

(1) 
Check bolt carrier for
chips, burrs, and cracks.

(2) 
Check bolt for cracks or
fractures, especially in the cam pin
hole area. Bolts that contain pits in
the firing pin hole need replacing.

(3) 
Check firing pin retaining
pin for bends and excessive wear.

(4) 
Check firing pin for bends,
cracks, and blunted or sharp end.

(5) 
Check cam pin for cracks
and chips.

(6) 
Check extractor for chipped
or broken edges in the area of the lip
that engages the cartridge rim. Check
to ensure the rubber insert is inside
the extractor spring.

d.
Report and turn in
unserviceable parts for maintenance.

5.   Lubricate the carbine.

Note.  
Under all but the coldest
arctic conditions, CLP is the
lubricant to use on the carbine.
Between +10 degrees Fahrenheit and -10
degrees Fahrenheit, either CLP or LAW
can be used. For -35 degrees
Fahrenheit or lower, use LAW only.

Note.  
Lightly lube means apply a film
of lubricant barely visible to the
eye.

Note.   Generously
lube means apply the lubricant heavily
enough so it can be spread with the
finger.

a.
Upper receiver and carrying
handle.

(1) 
Upper receiver. Lightly
lube inside of receiver, bore,
chamber, locking lugs, outer surfaces
of barrel and front sight, and mating
surface for carrying handle.

(2) 
Carrying handle. Apply a
drop or two of lubricant to both
threaded studs. Lightly lube the
clamping bar and both round nuts.
Lightly lube the mating surface.

(3) 
Front sight detent. Depress
and apply two or three drops of CLP to
front sight detent. Depress several
times to work lube into the spring.

(4) 
Adjustable rear sights. Use
one or two drops of CLP. Rotate the
following parts to ensure lubricant is
spread evenly above and below:

(a)
Elevation screw shaft.

(b)
Elevation knob.

(c)
Windage knob.

(d)
Windage screw.

b.
Lower receiver group.

(1) 
Lightly lube inside and
outside lower receiver extension,
buffer, and action spring. Lightly
lube inside buttstock assembly.
Generously lube buttstock lock-release
lever and retaining pin.

(2) 
Generously lube takedown
pin, pivot pin, detents, and all other
moving parts and their pins.

c.
Bolt carrier group.

(1) 
Lightly lube charging
handle and inner and outer surfaces of
bolt carrier.

(2) 
Place one drop of CLP in
the carrier key.

(3) 
Apply a light coat of CLP
on firing pin and firing pin recess in
bolt.

(4) 
Generously lube outside the
bolt body, bolt rings, and cam pin
area.

(5) 
Apply a light coat of CLP
on extractor and pin.

6.   Assemble the carbine.

a.
Install buttstock assembly.
Align the buttstock assembly with
lower receiver extension; pull
downward on the lock release lever
near the retaining pin, and slide the
buttstock assembly onto the lower
receiver extension.

b.
Insert action spring and
buffer.

c.
Insert extractor and
spring.

d.
Push in extractor pin.

e.
Slide bolt into carrier.

WARNING:
Be sure the
cam pin is installed in the bolt
group. If it is not, the carbine can
still fire and will explode.

f. 
Replace bolt cam pin.

g.
Drop in and seat firing
pin.

h.
Pull bolt back.

i.  
Replace retaining pin.

j.  
Engage, then push charging
handle in part of the way.

WARNING:
Do not
exchange or switch bolt assemblies
from one M4 or M4A1 to another.

k.
Slide in bolt carrier
group.

l.  
Push in charging handle and
bolt carrier group together.

m.  
Join upper and lower
receivers.

n.
Engage receiver pivot pin.

o.
Close upper and lower
receiver groups. Push in takedown pin.

p.
Replace handguards.

q.
Replace sling.

7.   Perform a function check on the M4 or M4A1 carbine
to determine correct functioning
according to Task 071-100-0005.

8.   Maintain M16/M4 magazine and ammunition.

a.
Maintain magazine.

(1) 
Disassemble magazine.


  • Insert the nose of a
    cartridge into the hole in the base of
    the magazine and raise the rear of the
    magazine until the indentation on the
    base is clear of the magazine.

  • Slide the base forward
    until free of the tabs.

  • Remove the magazine
    spring and follower (do not separate).

(2) 
Clean all parts using a rag
soaked with CLP. Dry all parts.

(3) 
Inspect parts for damage
such as dents and corrosion. If any
damage is found, turn in to
maintenance.

(4) 
Lubricate the magazine.
Lightly lube the spring only.

(5) 
Assemble the magazine.


  • Insert the follower and
    spring in the magazine tube and jiggle
    the spring to seat them in the
    magazine.

  • Slide the base under all
    four tabs until it is fully seated.
    Make sure the printing is on the
    outside.

b.
Maintain ammunition.

(1) 
Clean ammunition with a
clean dry rag.

(2) 
Inspect 
and turn in any ammunition with
the following defects: corrosion,
dented cartridges, cartridges with
loose bullets, and cartridges with the
bullet pushed in.

Evaluation Preparation: 

Setup: Have soldiers use their own weapons and magazines. Provide
swabs, cleaner, lubricant, preservative (CLP),
pipe cleaners, lubricating oil, and rifle
bore cleaner (the soldier should not select
rifle bore cleaner for use). Also provide
several rounds of dummy ammunition, if
available.

Brief
Soldier: Tell the soldier to clean,
inspect, and lubricate the weapon and
magazine following normal safety practices.

Performance
Measures

GO

NO GO

1.   Cleared the carbine.

2.   Disassembled the carbine.

3.   Cleaned the weapon using the correct materials.

4.   Inspected for unserviceable parts.

5.   Assembled the carbine.

6.   Performed a function check.

7.   Disassembled the magazine.

8.   Cleaned the magazine.

9.   Assembled the magazine

10. Cleaned the ammunition.

Evaluation
Guidance:
 
Score the soldier GO if all
performance measures are passed. Score the
soldier NO GO if any performance measure is
failed. If the soldier scores NO GO, show
him what was done wrong and how to do it
correctly.

References


 

Required


Related


 

 

TM
9-1005-319-10