Mk19 Sear Assembly

Whenever a new receiver sear is installed, also install a new bolt sear. Adjust the gun's timing.

(Army: Evacuate to Direct Support Maintenance.)

1. Inspect receiver sear (1) for wear. Replace if worn, observing NOTE, above.

Receiver sear shoulder is worn.

PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS) - Continued

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

17

Assembly (Continued)

2. Using a dial caliper, measure the length of the sear spring (2). If it is shorter than 0.960, discard and install a new spring. (Army: Evacuate to Direct Support Maintenance.)

3. Move the thumb safety (3) back and forth to ensure it snaps into and remains in both the 'S' (SAFE) and 'F' (FIRE) positions. (Army: Evacuate to Direct Support Maintenance.)

4. Inspect for broken parts and adequate lubrication.

5. Assure that the safety lever pin (4) is installed.

Sear spring measurement is less than 0.960.

Safety binds or does hold in safe/fire position.

Parts are broken or missing.

Mk19 Sear Assembly
1LK076

PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS) - Continued

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

18

(MK 19 UGWS only)

Inspect the electrical connector receptacle for damage.

Connector is damaged.

19

Removal

Appropriate eye protection is recommended when cleaning the weapon and/or its parts.

Cup is cracked. Set screw or cap screw(s) are missing.

20

*

Check feed slide adjustment. (Army: Feed slide adjustment will be performed at the Direct Support level).

WARNING

Ensure stow pin and depression stop are installed before attaching MK 64 mount to tripod (Refer to TM 9-1010-231-13&P).

Do not relink or fire ammunition which has been cycled through the weapon.

Assemble the weapon and mount it on the MK 64 Machine Gun Mount, MK 16 MOD 0 Stand, or M3 Tripod.

1. Raise the top cover and assure the bolt is in the forward position.

Functional check is to be performed only when one or more of the following parts has been replaced: feed slide assembly (inner/outer feed slide, feed pawls), secondary drive lever assembly, primary drive lever, primary pawl, bolt, top cover, or feed tray.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

20

Check

(Continued)

2. Feed two linked dummy rounds of 40mm ammunition into the weapon until the first round is to the right of the secondary pawl.

3. Move the feed slide assembly to the left and close the top cover. Charge weapon and push the chargers forward and up. Verify that the chargers do not bind when the weapon is charged.

4. Without opening the top cover, verify the second round is now to the right of the secondary pawl. The feed pawl will protrude when felt from the front underside of the feed tray area. Primary and secondary pawls should be in the up position.

5. Move the safety to 'F' (FIRE). Press the trigger to release the bolt forward under spring tension. Raise the top cover. Verify the extractors are seated properly on the ammunition case rim and delinking has occurred. Close top cover.

6. Pull the bolt to the rear until the primary pawl clicks prior to complete charging of the bolt. Push the chargers fully forward and up.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

20

Check

Catch the ejected dummy round as it comes out the bottom of the weapon. The round's ogive may become dented if the round is dropped.

7. Press trigger to release bolt forward. Charge the weapon, catching the ejected round. Place thumb safety on 'S' (SAFE).

8. Raise top cover and verify the ammunition is seated firmly against the bolt face and that the round stop pawl protrudes from the bolt face above the seated ammunition.

9. Verify no malfunctions occurred and no discrepancies were noted during accomplishment of steps 1 through 8.

10. Remove dummy ammunition from the weapon using a cleaning rod section.

11. Install the feed throat and insert a belt of six linked dummy rounds. Verify weapon met requirements of steps 3 through 6 when repeated with the six linked rounds of dummy ammunition.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

20

Check

To prevent dented ogive, catch the ejected dummy round as it comes out of the bottom of the weapon.

12. Remove last dummy round from the weapon, using a cleaning rod section.

13. With rounds removed, charge the weapon and return charging handles forward and in up position. Press trigger and release bolt. Raise the cover and inspect the bolt face to insure that the firing pin protrudes.

14. Charge the weapon again and return the charging handles to the forward position, leaving one charging handle down. Press the trigger and release the bolt. Raise the cover and inspect bolt face to insure that the firing pin does not protrude. This procedure is to confirm stoppage of a runaway gun.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

21

Every 6 months

Detailed Technical Inspection (DTI) (Not for Army use)

WARNING

Appropriate eye protection is recommended when cleaning the weapon and/or its parts.

Detail strip, clean, and inspect the weapon. (Training Commands may establish their own criteria.) A DTI should also be performed if the weapon is immersed in water or is extremely dirty.

22

Every 6 months

Bolt and Backplate Assembly (DTI) (Not for Army use)

WARNING

Appropriate eye protection is recommended when cleaning the weapon and/or its parts.

CAUTION

Do not immerse the cam followers, sear buffer, or the assembled bolt buffer assemblies in cleaning solvent. Solvent damages these parts.

Do not lubricate the internal components in the bolt buffer assemblies. Ensure the components are clean, dry, and not lubricated during assembly or excess recoil will result.

1. Detail strip, clean, and inspect the bolt and backplate assembly.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

22

Every 6 months

Backplate

Assembly

(Not for

Army use)

(continued)

2. Replace any parts required.

3. Verify all springs are not bent, broken, or worn on outer coils. Measure the length of all springs (WP 0057 00).

4. Inspect the mouth of the rods and tubes for burrs. Remove burrs with a stone. Verify rods and tubes are not bent.

NOTE

Anytime the cam followers or the covers, RH and LH, are removed, install new nylon point set screws, flat head screws, and socket head screws.

Adjust the bolt's timing each time the bolt is detail stripped or any of the following items are installed as new parts:

Bolt sear

Sear buffer rod

Buffer washers

Firing pin

Firing pin sear

Lock plate assembly or any of its components.

5. Lubricate and reassemble observing all NOTES mentioned above.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

23

Every 6 months

Assembly (DTI) (Not for Army use)

WARNING

Appropriate eye protection is recommended when cleaning the weapon and/or its parts.

CAUTION

Do not mix up the order or position of the components inside the receiver buffer bodies. Improper sequence or position of these components will cause excess recoil with possible parts damage (WP 0051 00).

1. Detail strip, clean, inspect, and lubricate the sear assembly.

2. Replace any parts required.

3. Verify all springs are not bent, broken, or worn on outer coils. Measure the length of all springs (WP 0057 00).

4. Lubricate and reassemble the sear assembly components.

Table 1. Preventive Maintenance Checks And Services For The MK 19 Mod 3 Machine Gun - Continued

ITEM NO.

INTERVAL

BE CHECKED

OR SERVICED

PROCEDURE

EQUIPMENT NOT READY/AVAILABLE IF:

24

Every 6 months

Other Assemblies (DTI) (Not for Army use)

1. Clean the other assemblies removing only the parts specified in the maintenance procedures for each assembly.

2. Inspect for worn, burred, broken, or missing parts.

3. Discard unserviceable parts and install new parts as required.

4. Verify all springs are not bent, broken, or worn on outer coils. Measure the length of all springs (WP 0057 00).

5. Lubricate and reassemble the weapon.

UNIT

MK 19 MOD 3 40 MM MACHINE GUN (NSN 1010-01-126-9063) UPGUNNED WEAPONS STATION MK 19 40 MM MACHINE GUN (NSN 1010-01-362-6513)

GENERAL MAINTENANCE INSTRUCTIONS

INITIAL SETUP:

Reference

WP 0124 00

GENERAL Initial Setup

The following information will reduce the space required for the initial setup portion of the maintenance procedures.

1. Materials/Parts required are not listed unless they apply to the procedure.

2. Personnel Required, is listed only if the task requires more than one person. If Personnel Required is not listed, it means one person can do the job.

3. The approximate time required is listed on the applicable Maintenance Allocation Chart (MAC).

4. When the term "evacuate to Direct Support [or Depot] Maintenance" is used, the entire MK 19 MOD 3/Upped Gun Weapon Station (UGWS) Machine Gun must be evacuated.

Lubrication

Whenever the words "lubricant," "lube," "LSA," "LSAT," "LAW" or "GMD" are cited in this TM, they are to be interpreted to mean weapons lubricating oil (LSA) (item 7, WP 0124 00), weapons lubricating oil (LSAT) (item 8, WP 0124 00), weapons lubricating oil (LAW) (item 6, WP 0124 00) or grease, molybdenum disulfide (GMD) (item 4, WP 0124 00) can be utilized as applicable. The following constraints must be adhered to:

1. Under all but the coldest arctic conditions, LSAT, LSA and GMD are the lubricants to use on the MK 19 MOD 3/UGWS, at 0 degrees fahrenheit and above.

2. LAW is the lubricant to use during cold arctic conditions (0 degrees fahrenheit and below).

3. Do not mix lubricants on the same MK 19. The weapon must be thoroughly cleaned during change from one lubricant to another. Dry cleaning solvent (SD) (item 10 or 11, WP 0124 00) is recommended for this purpose.

4. Rifle bore cleaner (RBC) (item 1, WP 0124 00) may be used to remove carbon buildup in the bore and other portions of the MK 19.

END OF WORK PACKAGE

UNIT

MK 19 MOD 3 40 MM MACHINE GUN (NSN 1010-01-126-9063) UPGUNNED WEAPONS STATION MK 19 40 MM MACHINE GUN (NSN 1010-01-362-6513)

MAINTENANCE OF THE MK 19 MOD 3 MACHINE GUN DISASSEMBLY/ASSEMBLY

DISASSEMBLY, ASSEMBLY

SL-3-00607A (Marine Corps only) Tool kit, small arms repairman,

SC-5180-95-CL-A07; Tool set, intermediate maintenance, SL-3-08669A (Marine Corps only) Tool set, organizational maintenance, SL-3-08668A (Marine Corps only)

DISASSEMBLY

Before performing any procedure, ensure the weapon is clear of any ammunition.

Do not allow the top cover to slam shut from raised position. Hand injury or equipment damage may result.

1. REMOVE FEED THROAT ASSEMBLY (MK 19 MOD 3 ONLY)

a. Squeeze shoulder pins (1) on feed throat and pull away from receiver (2).

INITIAL SETUP:

Tools and Special Tools

Tool kit, small arms repairman,

SC 4933-95-CL-A07 with addition of

Equipment Condition

Weapon on 'S' (SAFE), clear of ammo, bolt in forward position.

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Responses

  • bisrat
    What do the washers in the sear of the mk 19 do?
    8 years ago
  • sabina
    How to disassemble mk19 sear?
    4 years ago
  • segan
    What are the four screws that need to be replaced on a mk19?
    3 years ago

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