Mk19 Cracked Sear Bolt

parts.

Install new f t's timing (WP 0069 00).

1LK034

SYMPTOM - Continued

Rounds will not fire.

FIRING PIN DID NOT SPRING FORWARD.

1. Check the bolt sear (1) for damage.

2. Check the firing pin sear (2) for damage.

3. Measure the springs (see WP 0057 00).

4. Replace any worn or broken parts. Test the firing pin operation again.

5. Verify that the pin springs forward.

6. Adjust the bolt's timing (WP 0069 00).

Firing Pin

END OF WORK PACKAGE

DIRECT SUPPORT

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

DIRECT SUPPORT TROUBLESHOOTING - ERRATIC FIRING

INITIAL SETUP:

Tools and Special Tools

Tool kit, small arms repairman,

SC-5180-95-CL-A07 Tool kit, small arms repairman, SC 4933-95-CL-A07 with addition of SL-3-00607A (Marine Corps only) Tool set, intermediate maintenance, SL-3-08669A (Marine Corps only) Tool set, organizational maintenance, SL-3-08668A (Marine Corps only)

References

WP 0057 00 WP 0059 00 WP 0068 00 WP 0069 00 WP 0076 00

SYMPTOM

Erratic firing.

MALFUNCTION

Loose or cracked right-hand (RH) and left-hand (LH) cam followers.

CORRECTIVE ACTION

Manually test the RH and LH cam followers (1) for looseness and check for cracks on the top. Tighten nylon point set screws (2) as required.

If cracked, replace RH and or LH cam follower. Install new nylon point set screw (WP 0068 00).

MALFUNCTION

Cracked or broken alignment guide flat spring.

CORRECTIVE ACTION

1LK020

LOOSE RH OR LH CAM FOLLOWERS OR NYLON POINT SET SCREWS

Tighten RH and LH cam followers (1). Tighten nylon point set screws (2).

CRACKS

Remove the alignment guide assembly from the receiver (WP 0059 00). Check the alignment guide flat spring (1) for cracks around the flat head screw and for breakage.

CRACKED OR BROKEN ALIGNMENT GUIDE FLAT SPRING

Disassemble the alignment guide assembly (WP 0076 00). Install a new alignment guide flat spring. Reassemble (WP 0076 00).

MALFUNCTION

Non-electrical wire missing or broken on bolt sleeves. CORRECTIVE ACTION

Remove the bolt and backplate assembly from the receiver (WP 0059 00). Check for the presence of non-electrical wire (1) on the bolt sleeves.

ILK038

NON-ELECTRICAL WIRE MISSING/BROKEN

Install non-electrical wire after adjusting bolt timing (WP 0069 00).

SYMPTOM - Continued

Erratic firing.

MALFUNCTION

Broken lock plate.

CORRECTIVE ACTION

With the bolt and backplate assembly removed from the receiver (WP 0068 00), check for a broken lock plate (1).

LOCK PLATE BROKEN

Remove the non-electrical wire, bolt sleeve, and damaged lock plate (WP 0068 00). After installing a new lock plate assembly (WP 068 00), adjust the bolt's timing (WP 0069 00).

MALFUNCTION

Worn adjusting screw or spring plunger. CORRECTIVE ACTION

Turn the adjusting screw (1) an equal number of turns in both directions. The screw should click each 1/4 turn. If it does not click, the spring plunger and/or the adjusting screw are worn.

Mk19 Machine Gun
ILK045
Mk19 40mm Bolt

1LK059

1LK059

ADJUSTING SCREW OR SPRING PLUNGER WORN

1. Remove the non-electrical wire, bolt sleeves, and lock plate assembly (WP 0068 00).

2. Disassemble the lock plate assembly (WP 0068 00).

3. Install a new spring plunger in the lock plate (WP 0068 00).

4. If the grooves in the adjusting screw are worn, also install a new adjusting screw (WP 0068 00).

5. Adjust the bolt's timing (WP 0069 00). MALFUNCTION

Broken or worn helical compression spring; missing or out of position sear buffer components.

CORRECTIVE ACTION

Turn the bolt upside down or on its face. Manually attempt to move the bolt sear (1). The bolt sear should not move easily. If it does, the helical compression spring is worn or broken, or the buffer components are out of position or missing.

Machine Gun Silhouette

SYMPTOM - Continued

Erratic firing.

DAMAGED, WORN, OR MISSING COMPONENTS

Remove the components (WP 0068 00) and inspect for broken helical compression spring and for components out of position or missing. If the helical compression spring is intact, measure it (WP 0057 00). Replace any broken, worn, or missing components. Before reassembly, adjust bolt timing (WP 0069 00).

MALFUNCTION

Bolt timing out of adjustment. CORRECTIVE ACTION

Adjust the bolt's timing (WP 0069 00). Install components as directed (WP 0068 00).

MALFUNCTION

Broken firing pin sear or bolt sear.

CORRECTIVE ACTION

Disassemble the bolt (WP 0068 00). Check for broken firing pin sear and firing pin sear springs. While disassembling bolt, check the bolt sear. Assemble and adjust the bolt's timing (WP 0069 00).

END OF WORK PACKAGE

DIRECT SUPPORT

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

DIRECT SUPPORT TROUBLESHOOTING - SLUGGISH FIRING

INITIAL SETUP:

Tools and Special Tools

Tool kit, small arms repairman, SC 4933-95-CLA07 with addition of 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)

Materials/Parts

Abrasive cloth (item 3, WP 0124 00) Lubricant (as required)

References

WP 0057 00 WP 0059 00 WP 0067 00 WP 0068 00 WP 0069 00 WP 0074 00 WP 0082 00 WP 0087 00

SYMPTOM

Sluggish firing.

MALFUNCTION

Carbon buildup or chrome erosion on bore and chamber.

CORRECTIVE ACTION

0 0

Responses

  • AWET
    Is mk 19 open or closed bolt?
    4 years ago

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