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071-312-4025 (SL1) - Maintain an M249 Machine Gun

Standards: Cleaned and lubricated the M249 machine gun; inspected parts; and turned in unserviceable parts. Assembled the gun and ensured it was operational. Cleaned and inspected linked 5.56-mm ammunition for serviceability. Turned in unserviceable ammunition.

Conditions: Given an M249 machine gun; linked 5.56-mm ammunition; cleaning kit with pipe cleaners, small-arms swabs, chamber and bore brushes, cleaning rod, wiping rags, scraper tool, and cleaner lubricant preservative (CLP). You have a requirement to maintain the weapon.

Standards: Cleaned and lubricated the M249 machine gun; inspected parts; and turned in unserviceable parts. Assembled the gun and ensured it was operational. Cleaned and inspected linked 5.56-mm ammunition for serviceability. Turned in unserviceable ammunition.

Performance Steps

Note. The M249 is available with old and new style barrels. Diagrams used here show the new-style barrel.

1.   Clear the M249 machine gun.

a. Move the safety to the fire position.

b. With your right hand, palm up, pull the cocking handle to the rear and lock the bolt to the rear.

c. Hold the cocking handle to the rear and move the safety to the safe position. Push the cocking handle forward to the locked position. Place weapon on safe.

d. Push the cocking handle forward to its locked position (you should hear a click).

e. Raise the cover and feed mechanism assembly. To check for brass, links, or ammunition-

(1)  Check the feed pawl assembly under the feed cover.

(2)  Check the feed tray assembly.

(3)  Lift the feed tray assembly and inspect the chamber.

(4)  Check the space between the bolt assembly and chamber.

(5)  Insert two fingers in the magazine well and feel for brass or ammunition.

f.  Close the cover and feed mechanism assembly. Move the safety to the fire position.

g. Pull the cocking handle to the rear, press the trigger, and ease the bolt forward.

2.   Disassemble the M249 machine gun.

WARNING: Ensure bolt is in forward position before removing drive spring, return rod, and transfer mechanism assembly

a. Remove the drive spring, return rod, and transfer mechanism assembly.

(1)  Raise the cover assembly. Pull the upper retaining pin at the rear of the receiver to the left. Let the butt pivot downward so the rear opening of the receiver is clear (figure 071-312-4025-1).


Figure 071-312-4025-1. Rear opening of the receiver

 

Note. The upper and lower retaining pins in the rear of the receiver are captured pins. Do not try to remove them completely during disassembly.

(2)  Hold the weapon with one hand on the buttstock. At the same time, push in and upward on the rear end of return rod and transfer mechanism assembly with thumb of other hand to release it from positioning groove. Withdraw return rod and transfer mechanism assembly and spring (figure 071-312-4025-2).


Figure 071-312-4025-2. Removal of the return rod and transfer mechanism assembly

 

(3)  Separate the spring from the return rod and transfer mechanism assembly (figure 071-312-4025-3).


Figure 071-312-4025-3. Removal of the spring

 

b. Remove the operating rod, slide assembly, and bolt assembly.

(1)  Pull the cocking handle to the rear to move operating rod, slide assembly, and bolt assembly out the rear of the receiver (figure 071-312-4025-4).


Figure 071-312-4025-4. Removal of the operating rod, slide assembly, and bolt assembly

 

(2)  Rotate the bolt clockwise to disengage the lug. Remove the bolt from the slide assembly. Separate the piston from the slide assembly by pressing the rearmost retaining pin to the left and lifting the piston off the slide assembly (figure 071-312-4025-5).


Figure 071-312-4025-5. Removal of the bolt and piston

 

c. Remove the heat shield. Hold the weapon with one hand. With the other hand, grasp the heat shield just forward of the barrel handle, and lift it off the barrel (figure 071-312-4025-6).


Figure 071-312-4025-6. Removal of the heat shield

 

d. Remove the barrel (figure 071-312-4025-7).

(1)  Ensure the folding handle on the new style barrel is in carrying (up) position.

(2)  Depress the barrel locking lever with your left hand. Grasp and lift the carrying handle with your right hand. Push the barrel forward.


Figure 071-312-4025-7. Remove the barrel

e. Remove the handguard (figure 071-312-4025-8)

(1)  Push the handguard retaining pin to the left using a section of the cleaning rod.

(2)  Pull downward and remove the handguard.


Figure 071-312-4025-8. Remove the handguard

 

f.  Remove the gas regulator.

(1)  Position the gas collar so you can insert the scraper assembly into the notch in the front left of the gas block.

(2)  Insert the tip of the scraper assembly in the notch; hold the scraper firmly in position (figure 071-312-4025-9).


Figure 071-312-4025-9. Insertion of the scraper assembly

 

(3)  Turn the collar counterclockwise and remove it (figure 071-312-4025-10).

(4)  Remove the gas regulator from the gas block (figure 071-312-4025-10).


Figure 071-312-4025-10. Removal of the gas regulator from the gas block

 

g. Remove the buttstock and buffer assembly.

Note. The upper and lower retaining pins in the rear of the receiver are captured pins. Do not try to remove them completely during disassembly.

(1)  Using a section of the cleaning rod, push the lowermost retaining pin to the left.

(2)  While supporting the trigger mechanism with one hand, use the other to pull the buttstock and buffer assembly rearward and remove it (figure 071-312-4025-11).


Figure 071-312-4025-11. Removal of the buttstock and buffer assembly

h. Remove the trigger mechanism by pulling rearward and down (figure 071-312-4025-12).


Figure 071-312-4025-12. Removal of the trigger mechanism

i.   Remove the gas cylinder.

(1)  Turn the gas cylinder to the left or right to release the locking spring.

(2)  Pull the gas cylinder forward to remove it (figure 071-312-4025-13).


Figure 071-312-4025-13. Removal of the gas cylinder

 

j.   Remove the bipod. The bipod should slip off the receiver easily. If it does not, turn the bipod left or right to loosen any dirt or corrosion (figure 071-312-4025‑14).


Figure 071-312-4025-14. Removal of the bipod

 

3.   Clean the M249.

WARNING: Do not use gasoline, kerosene, hydraulic oil, benzene, benzol, high-pressure water, steam, or compressed air for cleaning

Note. Do not use abrasives to clean the bore, piston, gas cylinder, or gas regulator.

a. Clean the bore and chamber using a bore brush, a chamber brush, CLP, and fresh swabs..

b. Clean the gas regulator using the scraper. Do not use CLP on the collar, gas block, or body.

(1)  Clean the gas vent hole (figure 071-312-4025-15).


Figure 071-312-4025-15. Cleaning the gas vent hole

 

(2)  Clean the central hole of the gas regulator with the appropriate part of the scraper by turning the scraper clockwise and pushing it inward toward the bottom of the housing (figure 071-312-4025-16).


Figure 071-312-4025-16. Cleaning the central hole

 

(3)  Clean the two grooves of the regulator body using the protruding tips of the scraper (figure 071-312-4025-17).


Figure 071-312-4025-17. Cleaning the grooves of the regulator body

 

c. Clean the gas cylinder and piston using the scraper. Do not use CLP on the gas cylinder or on the piston.

(1)  Clean the front interior of the gas cylinder (repositioned in receiver with bipod in place) by inserting and turning the flat side of the scraper in a full 360-degree circular motion (figure 071-312-4025-18).


Figure 071-312-4025-18. Cleaning the gas cylinder's front interior

 

(2)  Clean the internal grooves on the front side of the gas cylinder as previously described (using the protruding tips of the scraper), but insert the scraper farther into the gas cylinder (figure 071-312-4025-19).


Figure 071-312-4025-19. Cleaning the gas cylinder's internal grooves

 

(3)  Clean the three grooves of the piston using a full, 360-degree circular motion (figure 071-312-4025-20).


Figure 071-312-4025-20. Cleaning the grooves of the piston

 

(4)  Clean the hole in the front of the piston by inserting and turning the flat side of the scraper in a full 360-degree circular motion (figure 071-312-4025‑21).


Figure 071-312-4025-21. Cleaning the hole in the piston

 

d. Remove carbon and dirt from all other parts of the weapon using CLP and a wiping rag.

e. Clean ammunition boxes with a brush and clean dry wiping rag.

f.  Clean ammunition with a clean dry wiping rag.

4.   Inspect the M249 machine gun.

a. Inspect the bore and chamber for chips and pitting.

b. Check the front sight for looseness.

c. Inspect the flash suppressor (old style barrel) or compensator (new style barrel), the barrel extension, and the barrel release for cracks, dents, burrs, or other damage.

d. Check the cover assembly for smooth operation, spring tension, bent parts, and excessive wear.

e. Check the cocking assembly for free movement and for bent or cracked parts.

f.  Check the rails for excessive wear, burrs, and chips.

g. Check the barrel locking latch and cover detect springs for spring tension.

h. Check for broken pistol grip and chipped or cracked trigger housing holding lug.

i.   Check the tripping lever and the seat for burrs, cracks, chips, or wear.

j.   Check the cocking action by pushing back on the tripping lever; the sear should rise. Pull the trigger; the sear should lower.

k. Check the safety function. Push the safety to the right (RED BAND NOT VISIBLE). Pull the trigger; the sear will not lower. Push the safety to the left (RED BAND VISIBLE). Pull the trigger again; the sear will lower.

l.   Check the slide assembly, bolt assembly, piston assembly, and return rod and transfer mechanism assembly for burrs, cracks, and broken pins. Push down on roller of slide assembly to ensure it retracts. Check the driving spring for broken strands.

m.   Check bipod legs for correct operation.

n. Check the rear sight assembly for serviceability.

o. Check the ammunition box for damage. Make sure the box latch will engage the receiver dovetail.

p. Inspect ammunition.

(1)  Check for damaged, corroded, or loose bullets.

(2)  Check for damaged links.

(3)  Report to your squad leader or NCOIC any deficiencies you cannot correct.

5.   Lubricate the M249.

Note. Use only CLP on the M249.

a. Lubricate exposed metal parts and all moving parts with a light coat of CLP.

b. Do not lubricate the gas regulator hole in the barrel or the gas regulator itself.

6.   Assemble the M249.

a. Replace the bipod and gas cylinder.

(1)  Place the bipod on the receiver.

(2)  Push the gas cylinder through the bipod yoke into the receiver.

(3)  Push the cylinder to the rear while countering the pressure of the locking spring and guiding the end of the cylinder into the receiver with the other hand applying downward pressure. When you have fully inserted the gas cylinder, rotate it until the spring clicks into place in the recess at the rear of cylinder (figure 071-312-4025-22).


Figure 071-312-4025-22. Replacement of the bipod and gas cylinder

 

b. Replace the handguard.

(1)  Stow the cleaning equipment in the handguard.

(2)  Place the handguard onto the receiver and slide it backward until it stops.

(3)  Using a cleaning rod section, push the handguard retaining pin to the right. This locks the handguard into position (figure 071-312-4025-23).


Figure 071-312-4025-23. Replacement of the handguard

 

(4)  Pull downward on the handguard to ensure it locks into position.

c. Replace the gas regulator.

(1)  Insert the gas regulator into the lower end of the hole in the gas block. Align the notch on the gas regulator body with the notch in the gas block (figure 071-312-4025-24).


Figure 071-312-4025-24. Replacement of the gas regulator

 

(2)  With the gas regulator installed and supported on a firm surface, place the gas collar on the protruding end of the gas regulator. Rotate the gas collar until it slips in place. To lock the gas regulator in place, press it in and rotate it (figure 071-312-4025-25).


Figure 071-312-4025-25. Replacement of the gas collar

 

d. Replace the barrel.

(1)  Depress the barrel locking lever with your left hand (figure 071-312-4025‑26).


Figure 071-312-4025-26. Replacement of the barrel

 

(2)  Hold the carrying handle with your right hand; pull the barrel rearward into the receiver. Push the carrying handle downward and release the barrel locking lever. Check to ensure the barrel locks into position.

e. Replace the trigger mechanism (figure 071-312-4025-27).


Figure 071-312-4025-27. Replacement of trigger mechanism

 

(1)  Pull the retaining pin to the left side of the receiver.

(2)  Align the trigger mechanism with the slot on the bottom of the receiver. To hold the trigger mechanism in place, push the lower retaining pin into the right side hole on the rear of the trigger mechanism assembly.

f.  Replace the buttstock and shoulder assembly (figure 071-312-4025-28). Support the trigger mechanism with your left hand. Align the lower hole in buttstock and buffer assembly with the rear hole in the trigger mechanism. Push the lower retaining pin to the right.


Figure 071-312-4025-28. Replacement of the buttstock and shoulder assembly

 

g. Replace the operating rod, slide assembly, and bolt assembly.

(1)  Secure the slide assembly to the piston by pushing the retaining pin from the left to the right. Place the firing pin spring on the firing pin (figure 071-312-4025-29).


Figure 071-312-4025-29. Attachment of the slide assembly to the piston

 

(2)  Put the bolt assembly into the slide assembly. Press in to compress the firing pin spring. Rotate the bolt and hook its driving lug into the slide assembly (figure 071-312-4025-30).


Figure 071-312-4025-30. Attachment of the bolt assembly to the slide assembly

 

(3)  Put the assembled parts into the receiver with the feed cover open. Align and place the bolt lugs; slide the cutouts carefully onto the receiver rails. Press the trigger and at the same time, push the parts all the way forward (figure 071-312-4025-31).


Figure 071-312-4025-31. Replacement of the operating rod, slide assembly, and bolt assembly

 

h. Replace the spring, return rod, and transfer mechanism assembly.

(1)  Put the slide spring on the return rod and transfer mechanism assembly (figure 071-312-4025-32).


Figure 071-312-4025-32. Replacement of the spring

 

(2)  Ensure that the headed end of the vertical pin in the transfer mechanism assembly points upward (on top of the transfer mechanism assembly) (figure 071-312-4025-33).


Figure 071-312-4025-33. Replacement of the return rod and transfer mechanism assembly

 

(3)  Hold the pistol grip with one hand. With the other hand, push the return rod and transfer mechanism assembly into its housing in the piston. Press inward and downward on the rear of the assembly until its two lugs move into the receiver grooves.

i.   Pivot the buttstock and buffer assembly upward into position. Push the retaining pin to the right, and close the cover assembly (figure 071-312-4025-34).


Figure 071-312-4025-34. Replacement of buttstock and buffer assembly

 

j.   Replace the heat shield assembly (figure 071-312-4025-35).


Figure 071-312-4025-35. Replacement of the heat shield assembly

 

(1)  Hook the metal extensions of the heat shield assembly under the front sight pins (new style barrel) with the spring clips down on top of the barrel.

Note. Although old style barrels do not have protruding front sight pins, you can still install heat shield assemblies on them.

(2)  Apply downward pressure and snap the heat shield onto the barrel. Be careful not to pinch yourself.

7.   Perform a function check to ensure you have assembled the weapon correctly.

Evaluation Preparation: 

Setup: At the test site, provide all the equipment and materials listed in task conditions.  Use only dummy ammunition for training purposes.

Brief Soldier: Tell the soldier to perform maintenance on the M249, ammunition box, and linked 5.56-mm ammunition.

Performance Measures

GO

NO GO

1.   Cleared the weapon.

--

--

2.   Disassembled the weapon without damaging any parts.

--

--

3.   Cleaned the weapon, ammunition box, and ammunition.

--

--

4.   Identified any damaged, worn, or malfunctioning part.

--

--

5.   Identified any damaged ammunition.

--

--

6.   Lubricated the weapon using the correct lubrication technique.

--

--

7.   Assembled the weapon in correct sequence without damaging any parts.

--

--

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 9-1005-201-10

FM 3-22.68