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071-030-0001 (SL1) - Maintain an MK19 Machine Gun

Standards: Cleaned and lubricated the MK 19 and its components. Inspected all parts and turned in those in need of maintenance. Reassembled the gun so it was operational. Cleaned and inspected ammunition for serviceability, and turned in any unserviceable ammunition.

Conditions: Given an MK19 machine gun, an M3 tripod, a traversing and elevating (T&E) mechanism, an M64 cradle mount; rifle bore cleaner (RBC), lubricant oil (LSA), or lubricating oil (LSAT or LAW); grease (GMD); cleaning solvent (PD680); wiping rags or cloth (abrasive crocus); a cleaning rod assembly and a small-arms cleaning brush; linked 40-mm ammunition and one spent 40-mm cartridge case.

Standards: Cleaned and lubricated the MK 19 and its components. Inspected all parts and turned in those in need of maintenance. Reassembled the gun so it was operational. Cleaned and inspected ammunition for serviceability, and turned in any unserviceable ammunition.

Performance Steps

1.   Clear the MK19.

a. Place the safe/fire switch in the SAFE (S) position. Ensure the bolt is forward.

b. Open the top cover and inspect the feed tray and extractors on the bolt face to ensure that no round is in the pickup position.

c. Unlock and pull charger handle 2 to 3 inches to the rear; inspect the face of the bolt and the chamber for ammunition.

d. Return the bolt to the forward position and rotate the charger handle to the locked position.

2.   Disassemble the MK19.

a. Remove the feed throat assembly (figure 071-030-0001-1). Squeeze the two sets of grip pins together and pull them straight out.

b. Remove the bolt and backplate assembly.

Figure 071-030-0001-1. Removal of feed throat assembly


WARNING: Make sure the bolt is in the forward position before you remove the backplate pin assembly. Failure to observe this warning will result in injury.

(1)  Place the safe/fire switch on FIRE (F).

(2)  Open the top cover.

(3)  Using the rim of a spent cartridge, pull the backplate pin straight out (figure 071-030-0001-2).

Figure 071-030-0001-2. Removal of backplate pin


(4)  Lift up slightly on the backplate assembly. Slowly pull the bolt and backplate assembly out of the receiver.

(5)  Support the bolt with one hand and maintain a control grip with the other hand. Lift the bolt up slightly and remove it (figure 071-030-0001-3).

Figure 071-030-0001-3. Removal of bolt and backplate assembly


c. Remove the primary drive lever and vertical cam assembly.

CAUTION: Do not rest the vertical cam assembly on its chromed surface.

(1)  Reach under the top of the receiver to locate the drive lever lock on the vertical cam assembly and slide the lock rearward about 1/4 inch (figure 071-030-0001-4).

Figure 071-030-0001-4. Primary drive lever and vertical cam assembly


(2)  Press down on the primary drive lever's pivot post. This releases the primary drive lever and vertical cam assembly (figure 071-030-0001-5).

Figure 071-030-0001-5. Removal of the primary drive lever and vertical cam assembly


(3)  Pull out the cam (to the rear) and the lever from the receiver.

d. Remove secondary drive lever.

(1)  Push down on the pivot post from the outside top cover. This releases the secondary drive lever (figure 071-030-0001-6).

Figure 071-030-0001-6. Removal of the secondary drive lever


(2)  Lift out the secondary drive lever from the top cover (figure 071-030-0001‑7).

Figure 071-030-0001-7. Secondary drive lever.


e. Remove the feed slide assembly (Figure 071-030-0001-8).

Figure 071-030-0001-8. Removal of the feed slide assembly.


(1)  Pivot the tray that holds the feed slide assembly out of the top cover.

(2)  Move the feed slide assembly to line up the tabs with the slots in the tray.

(3)  Lift upward on the feed slide assembly.

f.  Remove the top cover assembly and feed tray (figure 071-030-0001-9).

Figure 071-030-0001-9. Removal of the top cover assembly and feed tray


CAUTION: Using your fingers only, not pliers, remove the top cover pins. Forcing the pin could break the small cross pin on the rod.

Note. The feed tray must be down for you to remove the top cover pins.

(1)  Hold the top cover straight up to align the end of the cross pin.

(2)  Pull straight out on the pins.

(3)  Lift off the top cover.

(4)  Lift the tray out of the feeder.

g. Remove the alignment guide assembly (figure 071-030-0001-10).

Figure 071-030-0001-10. Removal of the alignment guide assembly


(1)  Depress the flat leaf spring by using a cartridge link toggle (male end) or a small tool.

(2)  Slide the alignment guide toward the feeder mouth.

(3)  Pull rearward on the alignment guide and lift it out.

h. Remove the ogive plunger by pulling it out (figure 071-030-0001-11).

Figure 071-030-0001-11. Removal of the ogive plunger


i.   Remove the round positioning block (figure 071-030-0001-12).

Figure 071-030-0001-12. Removal of the round positioning block


(1)  Grasp the two control grips with both hands and lift up slightly to disengage the backplate from the locking lugs in the receiver.

(2)  Pull the round positioning block toward the muzzle end of gun.

j.   Remove the charger assemblies (both sides) (figure 071-030-0001-13).

Figure 071-030-0001-13. Removal of the charger assembly


(1)  Rotate the charger handle up.

(2)  Using either your fingers or a spent case, pry out on the lip of the lock plunger.

(3)  Lift up on the lock plunger to retract it; slide the charger assembly all the way to the rear.

(4)  Pull the charger assembly away from the receiver.

k. Remove the receiver sear assembly (figure 071-030-0001-14).

Figure 071-030-0001-14. Removal of the receiver sear assembly


(1)  Turn the receiver on its top. Put the safe/fire switch in FIRE (F) position.

(2)  Lift up slightly on the lock pin with your fingers, using a cartridge link.

(3)  Squeeze the receiver sear (underneath the safety) and simultaneously rotate the sear housing assembly approximately 15 degrees in either direction.

(4)  Press down on the sear housing assembly and rotate the assembly until it stops (90 degrees from its original position).

(5)  Press the receiver sear and safety together while you put safe/fire switch on safe (S). This locks the sear in the down position and keeps you from accidentally losing the sear spring.

(6)  Lift out the sear housing assembly.

3.   Clean the parts of the MK19.

Note. Do not reverse the direction of the bore brush while it is in the bore.

a. Clean the receiver assembly (figure 071-030-0001-15).

Figure 071-030-0001-15. Receiver assembly


(1)  Apply solvent to a rag or brush. Wipe or brush dirt away from all parts, especially the interior of the receiver housing, receiver rails, and feeder.

(2)  Swab out the bore and chamber, using a bore brush and RBC.

(3)  Wipe all parts dry.

b. Clean the receiver sear assembly (figure 071-030-0001-14).

(1)  Use only cleaning solvent on a rag or brush.

(2)  Wipe or brush away dirt.

(3)  Wipe dry.

WARNING: Never immerse the sear housing assembly in solvent. Solvent may dilute the lubricant inside the sear housing.

c. Clean the alignment guide assembly, ogive plunger, round positioning block, and secondary drive lever; wipe or brush off dirt and dry.

WARNING: Never immerse the ogive plunger assembly in solvent.

d. Clean the charger assemblies.

(1)  Apply cleaning solvent to a rag or brush, and wipe or brush off dirt.

(2)  Wipe dry.

e. Clean the vertical cam assembly, primary drive lever, feed slide assembly, and feed tray.

(1)  Soak in cleaning solvent.

(2)  Wipe or brush off dirt.

(3)  Wipe dry.

f.  Clean the top cover assembly.

(1)  Apply cleaning solvent to a rag or brush and wipe or brush off dirt from all parts.

(2)  Wipe all surfaces dry.

g. Clean the bolt and backplate assembly.

(1)  Apply cleaning solvent to rag or brush and wipe or brush off dirt from all parts.

(2)  Wipe all surfaces dry.

4.   Clean the components.

a. Clean the T&E mechanism.

(1)  Remove foreign matter with a clean, dry wiping rag.

(2)  Use small arms cleaning brush to clean the numbers on the scale.

b. Clean the M3 tripod, MK64 gun cradle mount, and pintle.

(1)  Use a cleaning swab saturated with carbon removing compound to remove dirt.

(2)  Wipe all parts dry with clean wiping rags.

5.   Clean ammunition. Remove foreign matter with a clean, dry wiping rag.

6.   Inspect all MK19 parts for serviceability.

a. Receiver assembly.

(1)  Check the receiver housing for cracks and rust.

(2)  Check the receiver rails for burrs and cracked welds.

(3)  Check the feeder pawls for burrs and lack of spring action. Check the pins for retention.

(4)  Check the barrel for carbon buildup and pitting in the bore and chamber.

(5)  Check the flash suppressor for dents, cracks, and erosion. Make sure minimal movement is maintained.

(6)  Check the rear sight for rust, binding, and broken or bent parts.

b. Receiver sear assembly.

(1)  Check for burrs on all parts.

(2)  Closely inspect the rear shoulder for burrs.

c. Alignment guide assembly.

(1)  Check the alignment guide spring for deformity, cracks, and looseness.

(2)  Check the pin for breaks and cracks.

d. Ogive plunger assembly and round positioning block.

(1)  Check the ogive plunger head for burrs and broken parts.

(2)  Check the round positioning block for weak spring action and loose or broken parts.

e. Charger assembly (left and right).

(1)  Check the grooved edges for burrs and bends.

(2)  Check the latches for spring action on detects.

(3)  Check the entire charger assembly for cracks, burrs, bends, and chips.

f.  Vertical cam assembly and primary drive lever.

(1)  Check the vertical cam assembly for bends, burrs, pits, scratches, and aluminum buildup on chromed surface (mirror-like surface).

(2)  Check the drive lever lock for looseness or binding.

(3)  Check the primary drive lever for burrs, especially around the pivot posts.

g. Secondary drive lever.

(1)  Check for missing retaining ring from the pivot post.

(2)  Check the pivot post and forked end for burrs.

h. Feed slide assembly and feed tray.

(1)  Check the feed pawls and feed tray for burrs and binding.

(2)  Check the guide rails for burrs.

i.   Top cover assembly.

(1)  Check the top cover housing for cracks and rust.

(2)  Check the latch for binding, looseness, and breaks.

j.   Bolt and backplate assembly.

(1)  Check the cocking lever for chips, burrs, and breaks.

(2)  Check the guide rods for binding and bends.

(3)  Check the recoil spring for weak action. Position the bolt end against a hard, flat surface and push up and down on backplate assembly.

(4)  Check the backplate pin for missing retaining spring.

(5)  Check for missing, loose or broken safety wire.

k. Report any deficiencies to supervisor.

7.   Inspect all components for serviceability.

a. T&E mechanism.

(1)  Inspect the hand wheels for smooth operation and rust. Check the threads for burrs and rust.

(2)  Check the traversing slide lock for spring action. Make sure the elevating mechanism sleeve fits on the traversing bar and clamps firmly.

(3)  Check the traversing and elevating scales for legibility.

(4)  Inspect the quick release pin and chain for burrs and rust; check for missing spring-loaded balls.

b. M3 Tripod.

(1)  Check for completeness of tripod; make sure all nuts and bolts are tightly secured.

(2)  Check for cracks on the legs and tripod head.

(3)  Check for missing, broken, or inoperative lock latch.

(4)  Check the pintle lock release cam for correct operation.

(5)  Check the locking action of the front leg clamping assembly.

(6)  Make sure the rear legs lock in the open position, the sleeve latch notch and the right leg slide notch engage completely, and the latch spring has good tension.

(7)  Check the telescoping, indexing, and locking actions of rear legs and front leg locking assembly.

c. MK64 gun cradle mount.

(1)  Check for missing or damaged parts.

(2)  Check for rust, cracks, and burrs.

(3)  Inspect pintle lock assembly for nut, bolt, and cotter pin. Check the pintle surface for burrs and rust.

d. Report any deficiencies to supervisor.

8.   Inspect ammunition for damage and corrosion. Turn in any unserviceable ammunition.

9.   Lubricate the MK19 and components. Do not use CLP, and do not mix lubricants.


1. Never immerse the sear housing, ogive plunger, or bolt assemblies in cleaning solvent. Solvent could dilute the lubricant or grease inside.

2. Never lubricate the MK19 with CLP.

3. Avoid mixing lubricants.

4. Completely wipe off all excess lubricants.


a. Lubricate lightly to moderately with LSAT, LSA, or GMD (never CLP). In cold weather (0 to -25 degrees Fahrenheit), use LSAT, LSA, GMD, or LAW. In extra cold weather (-25 degrees Fahrenheit and below), use LAW.

b. Apply lubricant to all weapon parts and surfaces except charger handles. Work in the lubricant by moving the parts.

c. Lubricate all components and wipe them with an oily rag to remove excess oil.

10. Assemble the MK19 machine gun.

a. Attach the charger assemblies (both sides) (figure 071-030-0001-16).

Figure 071-030-0001-16. Attachment of the charger assemblies


(1)  Turn the receiver upright.

(2)  Rotate the charger handles to the straight-up position.

(3)  Line up the lugs on the charger with the slots in the receiver rail. Insert the charger lugs into the slots.

(4)  Hold the charger tightly against the rail. Slide the charger forward until it locks into place.

b. Attach the round positioning block (Figure 071-030-0001-17).

Figure 071-030-0001-17. Attachment of the round positioning block


(1)  Insert the blocks into the slots with the tang end forward.

(2)  Push against the block and slide it toward the rear until the block locks into place.

c. Insert the ogive plunger assembly into the opening.

d. Insert the alignment guide assembly (figure 071-030-0001-18).

Figure 071-030-0001-18. Insertion of the alignment guide assembly


(1)  Position the alignment guide assembly so the pin is lined up with the slot in the feeder wall.

(2)  Hold the alignment guide against the front wall and slide the alignment guide into the receiver until it clicks.

e. Attach the feed tray and feed slide assembly (figure 071-030-0001-19).

Figure 071-030-0001-19. Attachment of the feed slide assembly


(1)  Place the tray in the top of the feeder, recessed side up.

(2)  The pinholes on the tray should line up with the lugs on the receiver.

(3)  Position the feed slide assembly by lining up the tabs with the slots on the tray.

(4)  Insert the tabs into the slots. Drop the feed slide assembly into the tray and move it slightly to ensure engagement.

f.  Attach the top cover assembly (figure 071-030-0001-20).

Figure 071-030-0001-20. Attachment of the top cover assembly


(1)  Ensure the feed tray is in the proper place in the receiver.

(2)  Place the top cover on the receiver. Line up the pinholes on the cover with the receiver's lug end and the pinholes on the feed tray.

(3)  Hold the top cover straight up. Insert the top cover pins on both sides. Fully insert the cross pin. Rotate the top cover so it is fully open.

WARNING: To avoid breaking the cross pin, be sure to insert it fully into the receiver before you close the top cover.

g. Engage the secondary drive lever (figure 071-030-0001-21).

Figure 071-030-0001-21. Engaging the secondary drive lever


(1)  Rotate the feed slide assembly and tray upward.

(2)  Engage the forked end of the secondary drive lever with the feed slide pin.

(3)  Press the raised pivot post through the hole in the stop cover.

(4)  Press the secondary drive lever against the top cover until it locks into place.

CAUTION: Be sure to engage the secondary drive lever with the feed slide pin, or the gun will not fire.

h. Engage the vertical cam assembly (figure 071-030-0001-22).

Figure 071-030-0001-22. Engaging the vertical cam assembly.


(1)  Slide the vertical cam assembly through the rear of the receiver. The raised portion should slide over the top of the receiver. The drive lever lock should be underneath.

(2)  Engage the forked end in the notch.

i.   Engage the primary lever (figure 071-030-0001-23).

Figure 071-030-0001-23. Engaging the primary drive lever


(1)  Hold the vertical cam assembly in place and slide the primary drive lever into the receiver.

(2)  Slide the primary drive lever lock to the rear and engage the pivot post lever through the holes in the receiver and vertical cam.

(3)  Slide the primary drive lever lock forward. (The primary drive lever lock is located on the vertical cam just beneath the top of the receiver).

j.   Insert the bolt and backplate assembly (figure 071-030-0001-24).

Figure 071-030-0001-24. Insertion of the bolt and backplate assembly


(1)  Place the safe/fire switch in the fire (F) position.

(2)  Press the receiver sear using your thumbs or the rim of a cartridge case.

(3)  Make sure the cocking lever is cocked and forward.

(4)  Slide the bolt and backplate assembly all the way forward.

(5)  Insert the backplate pin to lock the assembly in place.

(6)  Close the cover.

WARNING: Before inserting the bolt and backplate assembly, put the cocking lever in the forward position.

CAUTION: Before closing the top cover, always make sure the secondary drive lever engages the feed slide pin, the feed slide assembly is to the left, and the bolt is forward. Never try to force the top cover closed. Doing so could damage the weapon.

k. Attach the receiver sear assembly (figure 071-030-0001-25).

figure 071-030-0001-25. Attachment of the receiver sear assembly


(1)  Turn the receiver over on its top.

(2)  Place the sear housing on the receiver and line up the sear housing assembly at a right angle to the barrel center line.

(3)  Put the safe/fire switch on fire (F) position.

(4)  Press down and rotate the housing assembly until it stops.

(5)  Press up on the sear and rotate it until it locks in position.

l.   Attach the feed throat assembly.

(1)  Squeeze the grip pins and align them with the holes in the receiver.

(2)  Release the grip pins to attach the feed throat.

11. Perform a function check to make sure you have assembled the weapon correctly.

Evaluation Preparation: 

Setup: At the test site, provide the soldier with the equipment listed in the task conditions. Use the performance steps in the training outline to evaluate the soldier's performance of the task.

Brief Soldier: Tell the soldier to perform operator level maintenance on the MK19 and to perform a function check to ensure the weapon functions correctly.

Performance Measures



1.   Cleared the weapon.



2.   Disassembled the weapon without damaging any parts.



3.   Cleaned the weapon parts.



4.   Cleaned the components.



5.   Cleaned the ammunition.



6.   Inspected all parts, components, and ammunition for serviceability.



7.   Reported all deficiencies to your supervisor.



8.   Lubricated the weapon parts and components using the correct lubricant and lubrication techniques.



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



10. Performed a function check.



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.







FM 23-27



TM 9-1010-230-10