Operator’s manual Machine gun, 7.62 mm, MK43 MOD 0

Safety information

Warnings

Keep Weapon Pointed at target - down range/limpact area.

Never stand in front of weapon or expose body or hands to breech, ejection port,

or muzzle.

Keep Safety on S until you’re ready to fire.

Always check the chamber/bore after clearing the weapon.

Check barrel bore and chamber before firing.

Change hot barrels by holdlng onto carrying handle.

(Refer to pages 61 and 84 for procedures.)

Be sure barrel lock lever Is locked down before charging and flring the gun.

Before starting Inspection, be sure to clear weapon (p 26).

If cover is opened on hot cartridge (hot barrel), an open cover cook-off could occur

and result In serious injury or death. Evacuate area for 15 minutes and then do

Immediate Action (p 32).

MK 43 MOD 0

iii

Never reload a runaway gun until it has been repaired.

Cautions

Be sure machine gun is cleared before moving it.

When removing a stuck unfired cartridge, stay clear of the muzzle. Do not allow

Do not use tip of driving spring guide assembly as a tool.

cartridge to contact any hard surface. Cartridge may fire on contact. Remove a stuck

Insert reamer carefully to prevent damage.

unfired cartridge using the same procedures for removing a stuck or ruptured

Do not get lubricant in gas system.

cartridge case.

The climate temperature in different regions will make a difference as to what

constitutes a hot gun. A hot, sunny day can cause a cookoff within 50 rounds, with

weapon and ammunition in sun.

Before field stripping, clear and check that the bolt is in forward position.

Bolt assembly is under spring tension. It can twist and injure your hand.

Barrels issued for a specific gun should not be changed from gun to gun. Each barrel

and bolt assembly should remain together as initially issued.

Only use authorized ammunition in machine gun.

Be sure Blank Firing Adaptor (BFA) is removed before firing live ammunition.

Do not fire blank ammunition towards personnel within 20 feet of muzzle. Fragments

of a closure wad or particles of unburned propellant might inflict injury within that range.

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MK 43 MOD 0

Contents

SAFETY INFORMATION

iii

Section II. Preventive Maintenance Checks and Services(PMCS)

Section Ill. Operation Under Usual Conditions

CHAPTER 1

Assembly and Preparation for Use

INTRODUCTION

Loading Ammunition in the MK43 MOD 0

Section I. General Information

Clearing and Unloading the MK43 MOD 0

Scope

Initial Adjustments, Daily Checks, and Self-Test

Section II. Equipment Description

Field Zeroing

Equipment Characteristics, Capabilities and Features

Operating Procedures Immediate Action

Location and Description of Major Components

Runaway Machine Gun

MK43 MOD 0 Machine Gun

Misfire

CHAPTER 2

Remedial Action (Steps to take if immediate action-misfire does not work) . . . 36

OPERATING INSTRUCTIONS

Removing Stuck or Ruptured Cartridge Case (When round fires

Section I. Description and Use of Operator’s Controls and Indicators1 0

but cartridge case does not extract)

MK43 MOD 0 Machine Gun

Section IV. Operation Under Unusual Conditions

Front Sight Adjustment

In Extremely Cold Climate

Trigger Guard

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MK 43 MOD 0

vii

In Hot, Wet Climate

Section IV. Cleaning and Inspection

In Hot, and Sandy Areas

Bolt Assembly and Operating Rod Assembly

After Exposure to Water

Cover Assembly and Cartridge Feed Tray Assembly

Barrel and Handle Assembly

CHAPTER 3

Trigger Mechanism Grip Assembly

MAINTENANCE INSTRUCTIONS

Receiver

Section I. Lubrication Guide and Instructions

Section V. Reassembling Machine Gun

Recommended Lubrication Areas

Forearm Grip, Sling Swivel and Bipod Assembly

Section II. Troubleshooting Procedures

Trigger Mechanism Grip Assembly

Introduction

Barrel and Handle Assembly

Section Ill. Field-Stripping Machine Gun Procedures

Cover and Cartridge Feed Tray Assembly

Shoulder Buttstock and Buffer Assembly

Bolt Assembly and Operating Rod Assembly

Shoulder Buttstock and Buffer Assembly

Cover and Cartridge Feed Tray Assembly

Assembly of Buttstock to Receiver

Barrel and Handle Assembly

Section VI. Maintenance Checklist

Trigger Mechanism Grip Assembly

Section VII. Machine Gun Check Out Procedure

Forearm Grip, Sling Swivel and Bipod Assembly

viii

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MK 43 MOD 0

CHAPTER 4

Chapter 1-introduction

AMMUNITION

APPENDIX A

Section I. general information

REFERENCES

APPENDIX B

Scope

COMPONENTS OF END lTEM AND BASIC ISSUE ITEMS LISTS

100

Section I. Introduction

100

Type of Manual: Operator’s Manual.

Section II. Components of End Item

103

Model Number and Equipment Name: MK43 MOD 0 7.62-mm Machine Gun.

Section III. Basic Issue Items

104

Purpose of Equipment: The MK43 MOD 0 7.62-mm Machine Gun is a light weight

APPENDIX C

general purpose weapon for assault use. The weapon is intended for hand held or

ADDITIONAL AUTHORIZED LIST

108

blpod supported firing. The weapon is also capable of being fired from standard

Section I. Introduction

108

mounts.

APPENDIX D

EXPENDABLE/DURABLE SUPPLIES AND MATERlALS LIST

110

Section I. Introduction

110

Section II. Expendable/Durable Supplies and Materials List

112

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MK 43 MOD 0

Section II. Equipment description

barrel

assembly

Equipment Characteristics, Capabilities and Features.

The MK43 MOD 0 is air-cooled and has fixed headspace allowing quick barrel

changes for cooling and maintenance when required. Two barrel assemblies are

cover assembly

issued with each gun. Barrels issued for a specific gun should not be changed

from gun to gun. Each barrel and bolt assembly should remain together as initially

received. The machine gun is gas operated and fires from the open bolt position.

Location and Description of Major Components.

MK43 MOD 0 Machine Gun

Cover Assembly. Positions and holds cartridge in place for stripping, feeding link belt

and chambering rounds.

Cocking Handle Assembly. Provides a means to manually move the bolt assembly to

cocking handle

the rear.

assembly

Trigger Mechanism and Grip Assembly. Controls the firing of the machine gun.

Barrel/Assembly. The barrel assembly houses cartridges for firing.

trigger mechanism

grip assembly

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MK 43 MOD 0

Carrying Handle Assembly. Provides a means to carry the machine gun and change

barrels with one hand. The carrying handle assembly folds left when the rear sight is

used and the machine gun is fired.

carrying handle

assembly

Receiver Assembly. Supports all major components. Houses internal parts and,

through a series of cam ways, controls operation of weapon.

Shoulder Buttstock. Provides a suitable surface to stabilize the weapon against the

shoulder

shoulder while firing the machine gun from any position except from the hip.

buttstock

Bipod Assembly. Provides a semi-stable platform when the machine gun is fired from

the prone position.

bipod assembly

receiver assembly

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MK 43 MOD 0

Cartridge Feed Tray Assembly. Guides cartridges for positioning and feeding.

Bandoleer Bracket Assembly. This assembly supports the ammunition bandoleer.

rear sight

Rear Sight Assembly. Provides a means to aim the machine gun at the target with

assembly

accuracy. The sigh adjusts horizontally as well as vertically.

cartridge feed

Forearm Grip Assembly. Provides a hand hold when firing from the hip or from the

tray assembly

standing or kneeling position.

Front Mounting Pin. Provides a means to attach gun to a pintle assembly.

forearm grip

front mounting

Bandoleer

assembly

bracket assembly

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MK 43 MOD 0

Equipment Data.

Rifling:

MK43 MOD 0 Machine Gun

Number of lands

Right hand twist

One turn in 12 in. (304.8mm)

Weight

20.8 lb. (9.4 kg)

Trigger pull:

Length:

Maximum

11.5 lb (5.2 kg)

Short Barrel

37.7 in. overall (958 mm overall)

Minimum

8.0 lb (2.7 kg)

Long Barrel

42.2 in. overall (1071mm overall)

Maximum Effective Range

1100 meters

Maximum Range

3725 meters

Tracer Burn Out

900 meters or more

Rates of fire:

Sustained

100 rd per min (4 to 6 seconds between bursts)

Recommend barrel change every 6 min

Rapid

200 rd per min (2 to 3 seconds between bursts)

Recommend barrel change every 2 min

Cyclic

500-650 rounds per minute

Recommend barrel change every min

Muzzle velocity

2800 fps (853 m/sec)

Capacity of bandoleer

100 rds

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MK 43 MOD 0

CHAPTER 2-OPERATING INSTRUCTIONS

SecTION I. DESCRIPTION & USE OF OPERATOR’S CONTROLS & INDICATORS

barrel lock lever

MK 43 MOD 0 Machine Gun

Cocking Handle. Pull back to move bolt rearward.

Cover Latch Lever. Holds cover closed. Pull back on lower end of latch to open.

COVER LATCH

Barrel Lock Lever. Locks barrel in place. To unlock barrel, push in on barrel lock lever

LEVER

from left side of weapon and raise lever.

Bipod Leg Lock. Depress to extend or retract bipod foot.

cocking

Trigger. Pull rearward to fire weapon. Release to stop firing.

handle

Safety Move safety up to F (fire) and down to S (safe).

bidpod leg lock

trigger

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MK 43 MOD 0

Rear Sight

REAR

SIGHT

RANGE

SCALE

Range Scale - use to judge target distance.

Scale Retaining/Adjusting Screw - locks range scale in place.

Elevating Knob - use for minor (fine) adjustments in range.

REAR SIGHT

Windage Scale - indicates left or right windage.

APERTURE

ELEVATING

Windage Knob -adjusts windage scale left or right.

KNOB

Rear Sight Aperture - lines up with front sight for long range targets.

SCALE RETAINING/

ADJUSTING SCREW

WINDAGE

KNOB

WINDAGE

SCALE

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MK 43 MOD 0

Operator/Crew PMCS

Section II. preventative maintenance checks and services (pmcs)

B - Before D - During A - After

Item

Interval

No.

Item to be inspected and procedure

General

Always keep in mind the Cautions and Warnings when performing your before (B) or

WARNING: Before starting inspection, be sure to clear

during (D) PMCS. After you operate, perform your after (A) PMCS.

weapon (p 26)

Perform before (B) PMCS if: (1) you are the assigned opperator and the machine gun

has been stored and not used for a period of 90 days or (2) you have been issued the

•

MK43 MOD 0 Machine Gun Tools and Equipment.

machine gun for the first time.

Visually check for missing or damaged tools and equipment.

•

Barrel Assembly. Open cover, pull bolt to rear, push cocking

handle forward and lock. Close cover, place on safe (S). Tilt weapon

end to end to make sure gas piston slides freely (a clicking sound

will be heard as the piston slides in the cylinder). Run a dry swab

through the bore to remove excess lubricant or obstructions.

Equipment is NOT ready/available if: Gas piston will not slide.

Obstruction in barrel.

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MK 43 MOD 0

Operator/Crew PMCS

B - Before D - During A - After

Item

Interval

Item

Interval

No.

Item to be inspected and procedure

No.

Item to be inspected and procedure

•

Trigger Mechanism Grip Assembly.

•

Gun Receiver Assembly. Check for free movement of cocking

1. Make sure that flat spring is in place (p 62).

handle. Check barrel lock lever. Make sure it locks barrel in place.

2. Check that Safety is in F position.

Equipment is NOT ready/available if: Cocking handle binds or

3. Pull bolt to the rear.

barrel is loose.

4. Move safety to S

5. Push charging handle foward and lock.

6. Pull the trigger.

•

MK43 MOD 0 Machine Gun. Erratic or sluggish firing may indicate

carbon build-up. Switch barrels (p 61). If firing is still erratic or

Equipment is NOT ready/available if: Weapon functions with

sluggish, field-strip the weapon and perform the necessary

safety at S.

maintenance (p 53) to complete the fire mission.

Equipment is NOT ready/available if: Weapon ceases to operate.

•

Cover Assembly. Lightly lubricate all moving parts before using.

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MK 43 MOD 0

Operator/Crew PMCS

Section III. Operation Under unusual conditions

B - Before D - During A - After

Item

Interval

No.

Item to be inspected and procedure

Assembly and Preparation for Use

•

MK43 MOD 0 Machine Gun. Field-strip (p 53) clean, inspect and

Loading Ammunition in the MK43 MOD0

lubricate entire weapon (p 44).

•

MK43 MOD 0 Machine Gun (Inspection). Inspect operating rod

assembly and barrel assembly for burrs, cracks and chips. Make

sure the gas piston slides back and forth freely. Inspect components

of trigger assembly for wear. Check safety in S position, sear

should move slightly and in F position, sear should move freely.

Inspect breech bolt assembly for defects - e.g., cracks or chips.

Reassemble weapon and check for proper functioning.

Equipment is NOT ready/available if: Weapon fails to function

properly or has damaged or missing parts.

1. Point weapon down range.

2. Move safety to F.

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MK 43 MOD 0

4. Move safety to S.

Clearing and Unloading the MK43 MOD 0:

WARNING: If cover is opened on hot cartridge (hot barrel), an open cover

1. Point weapon down range.

cook-off could occur and result in serious injury or death. Evacuate area for 15

2. Move safety to “F”

minutes and then do Immediate Action, (p 30).

3. Pull cocking handle rearward to the charged position then push it

5. Turn latch lever and open cover.

forward until it locks.

safety

cocking

handle

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MK 43 MOD 0

6. Remove ammunition and link belt and raise feed tray.

7. Inspect chamber. If empty, go to step 8. If a round is

chambered, see page 38 for stuck or ruptured

cartridge case and page 47 for trouble-shooting.

latch lever

cover

feed tray

trigger

chamber

receiver

8. Lower feed tray.

9. Close cover. Cover latch should catch and hold cover closed.

10. Move safety to F. Pull cocking handle rearward and hold it. Pull trigger and allow

cocking ahndle to move forward slowly.

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MK 43 MOD 0

Initial Adjustments, Daily Checks, and Self-Test

RANGE

SCALE

Field Zeroing

REAR SIGHT

1. Choose a target between 300 and 700 meters.

APERTURE

ELEVATING

2. Set range scale on rear sight to 500 meters.

KNOB

3. Zero windage scale with index line.

SCALE RETAINING/

4. Aim at six o’clock on bottom of target.

ADJUSTING SCREW

5. Fire burst of 6 to 9 rounds and observe impact of burst.

6. Correct for left or right wind by adjusting windage knob. Then correct range by

adjusting elevating knob. Adjust until a burst of 6-9 rounds is on target.

WINDAGE

KNOB

7. Loosen scale retaining/adjusting screw and adjust range scale so 500 meter mark

is on top of slide.

Note

One mil is equal to one meter at 1000 meters.

WINDAGE

SCALE

index

line

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MK 43 MOD 0

3. Pull cocking handle all the way back and hold it. Place safety to S and remove

Operating Procedures Immediate Action

link belt.

4. Clear machine gun (pg 26).

Runaway Machine Gun

5. Notify organizational maintenance for repairs.

WARNING: Never reload runaway gun until it has been repaired. Be sure machine

gun is cleared before moving it.

link belt

WARNING: Always keep machine gun pointed down range.

1. If runaway occurs (machine gun won’t stop firing), take the following actions to

correct it quickly.

move safety to s

2. Break link belt (grasp belt and twist firmly) or let machine gun fire if near end of

link belt.

cocking handle

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MK 43 MOD 0

WARNING: If cover is opened on a hot cartridge (hot barrel), and open cover

Misfire

cook-off could occur and result in serious injury or death. Close cover and

If weapon stops firing before you complete your mission, take immediate action within

evacuate area for 15 minutes.

10 seconds.

4. If nothing is ejected and the barrel is hot enough to cause a cookoff (200 rounds

1. Pull cocking handle rearward.

fired within 2 minutes), wait at least 15 minutes (make sure bolt is locked rearward).

2. Check ejection port.

Repeat steps for Immediate Action.

3. If a round or cartridge case is ejected, push cocking handle forward and fire again.

5. If Immediate Action fails to remove cartridge case, take Remedial Action (pg 36).

cocking handle

Fire

again

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MK 43 MOD 0

1. Keep weapon on target (down range/impact area). Clear weapon when barrel is

Remedial Action (Steps to Take if Immediate Action Misfire Fails)

cool (after 15 minutes wait) using the following steps.

2. Pull cocking handle rearward, to the charged position.

WARNING: If cover is opened on a hot cartridge (hot barrel), and open cover

3. If a round is not ejected, move safety to S.

cook-off could occur and result in serious injury or death. Close cover and

4. Open cover, remove ammunition link belt and raise feed tray.

evacuate area for 15 minutes.

5. Inspect receiver, chamber, extractor, and ammunition.

6. If a round is in chamber, lower feed tray and close cover.

7. Push cocking handle forward.

8. Move safety to F.

9. Attempt to fire.

10. If a round is fired and ejected, reload and continue to fire.

11. If a weapon does not fire or eject, clear and unload weapon, and notify

danger

organizational maintenance for repair.

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MK 43 MOD 0

Removing Stuck or Ruptured Cartridge Case

(When Round Fires but Cartridge Case Does Not Extract)

WARNING: When removing a stuck unfired cartridge, stay clear of the muzzle.

Do not allow cartridge to contact any hard surface. Cartridge may fire on contact.

Remove a stuck unfired cartridge using the same procedures for removing a

stuck or ruptured cartridge case.

1. Pull cocking handle rearward to the charged position, and move safety to S.

2. Remove barrel. See page 53, Field Stripping.

4. Ruptured cartridge case-

a. Push ruptured cartridge extractor inside ruptured case in chamber until it seats.

3. Stuck cartridge case/unfired cartridge-Insert cleaning rod in muzzle and tap out

case/cartridge.

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MK 43 MOD 0

b. Lightly tap out ruptured cartridge with cleaning rod.

5. Install barrel. See Reassembly on page 84.

c. Remove extractor from cartridge case.

6. Close cover.

d. Unscrew extractor tool and remove cartridge case. Reassemble tool.

7. Hold cocking handle rearward.

8. Move safety to F.

9. Pull trigger and ease cocking handle forward.

10. Once weapon is cleared, do not move safety to S when bolt is forward.

Leave safety at F.

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MK 43 MOD 0

In Extremely Cold Climate:

section IV. Operation under unusual conditions

Lubricate according to Lube Guide (pg 44). Keep weapon free of moisture.

WARNING: The climate temperature in different regions will make a difference

In Hot, Wet Climate:

as to what constitutes a hot gun. A hot, sunny day can cause a cookoff within 60

Lubricate and inspect more frequently. Use a light coating of lubricant and keep

rounds, if the weapon and ammunition are left in the direct sun.

weapon dry.

In Hot, and Sandy Areas:

Inspect daily and clean frequently. Wipe lubricant from exposed surfaces and keep

sand out of parts. Cover weapon as much as possible.

After Exposure to Water:

First make sure weapon is dry before lubricating. Then disassemble,

clean, lubricate, and reassemble as soon as possible.

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MK 43 MOD 0

1. Under all but the coldest arctic conditions, LSA or CLP can be used on your

chapter 3-Maintenance Instructions

machine gun. Remember to remove excessive oil from the bore before firing.

2. Lightly Lube-A film of oil barely visible to the eye.

section I. Lubrication Guide and Instruction

3. Generously Lube-Heavy enough so that It can be spread with the finger.

4. External Surfaces. Put lubricant (item 1, 2 or 3, a p D) on a clean swab (item 5, app

D) and generously lubricate alI shaded areas. Lightly lubricate all other areas

except rubber-coated parts.

rollers

LSA - Lubricating Oil

pawl

CLP - Lubricating Oil, Semifluid Weapons

0 F

Between 0°F And -35°F Either CLP Or Law

feed tray

LAW - Lubricating Oil, Weapons

-35 F

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MK 43 MOD 0

Recommended Lubrication Areas

section II. Troubleshooting procedures

front cartridge guide

Introduction

roller

The table lists the common malfunctions which you may find during the operation

feed cam

or maintenance of the machine gun or its components. You should perform the test/

inspections and corrective actions in the order listed.

rails

This manual cannot list all malfunctions that may occur nor all tests or inspections and

rear cartridge

corrective actions. If a malfunction is not listed or is not corrected by listed corrective

guide

locking

actions, notify your supervisor.

lug

roller

WARNING: Keep weapon pointed at target impact area. Never stand in front of

weapon or expose body or hands to breech, ejection port, or muzzle.

camming recess

receiver

rails

camming locking surfaces

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MK 43 MOD 0

Malfunction

Test or Inspection

Corrective Action

Malfunction

Test or Inspection

Corrective Action

Cook Off*

Hot Barrel- If you have fired 200

Cool weapon for 15

Failure to Extract

Broken extractor or spring.

Notify organizational

or more rounds within 2 minutes

minutes

maintenance.

(rapid rate of fire), barrel will be

hot enough to cause cook off.

Short recoil.

Clean gas port,

piston, gas cylinder,

operating rod, and

Failure to Fire

Check ammunition.

Replace faulty

chamber (73-76, 79).

ammunition.

Dirty ammunition or chamber.

Clean chamber

Check for broken or damaged

and/or use new

firing pin.

Notify

ammunition.

organizational

Check for weak or broken firing

mainentance.

Sluggish Operation

Friction from dirt, carbon, burrs, or

Clean/lubricate or

pin spring, guide assembly, or

lack of lubrication.

notify organizational

compression spring.

mainentance.

Wadding and

Manually charge weapon (if firing

Clean/lubricate or

Unburned Powder

blanks).

notify organizational

*COOKOFF - A misfire of a chambered round caused by the weapon overheating.

mainentance.

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MK 43 MOD 0

Malfunction

Test or Inspection

Corrective Action

Malfunction

Test or Inspection

Corrective Action

Failure to

Ruptured cartridge case.

Remove (pg 38).

Failure to Eject

Frozen or damaged ejector

Notify organizational

Chamber

spring.

maintenance.

Carbon build-up in gas cylinder.

Remove carbon.

Short recoil.

Clean gas port,

Carbon build-up in receiver

Remove carbon.

piston, gas cylinder,

assembly.

chamber, and

operating rod tube

Damaged round.

*Remove round and

(pg 73-76 & 79).

recharge weapon.

Failure to Cock or

Operating rod sear notch or sear

Notify organizational

Dirty chamber.

Clean or replace

Runaway Gun

worn.

maintenance.

barrel.

Sear plunger or spring broken or

Notify organizational

missing.

maintenance.

* Dispose of damaged round according to range SOP.

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MK 43 MOD 0

Malfunction

Test or Inspection

Corrective Action

section III. Field-stripping machine gun procedures

Failure to Feed

Insufficient gas pressure (short

Clean gas system,

Shoulder Buttstock and Buffer Assembly

recoil).

barrel, chamber and

socket (p 73-76).

WARNING: Before field stripping, clear and

verify that the bolt is in the forward position.

Improper lubrication.

Lubricate as

yoke

neccessary (44-46).

1. Clear the weapon.

Defective ammunition or links.

Use new ammunition

2. Close cover.

belt.

3. Hold cocking handle rearward.

4. Move safety to F.

Ammunition belt installed wrong.

Install with open side

of link down (p 24).

5. Pull trigger and ease cocking

handle forward slowly. The

Damaged or weak operating

Notify organizational

breech bolt should now be in

parts.

maintenance.

the forward position.

6. Open cover.

Obstruction in receiver assembly.

Remove.

7. Push the buttstock forward in

the direction shown and remove the yoke.

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MK 43 MOD 0

WARNING: Drive spring and drive spring guide are under spring tension. These

10. Remove the buffer assembly from the buttstock as shown.

parts may eject when the buttstock is being removed from the receiver. Avoid

exposing your body to ejection parts.

8. Slide the buttstock off the end of the receiver.

9. Remove the drive spring and drive spring guide from the receiver.

buffer

assembly

buffer assembly

receiver

drive spring

guide

buttstock

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MK 43 MOD 0

4. Push operating rod assembly toward rear of slot in bolt assembly.

Cover and Cartridge Feed Tray Assembly

5. Separate operating rod assembly from bolt assembly.

CAUTION: Do not use tip of driving spring guide assembly as a tool.

1. Use a round (cleaning rod) or similar item to unlatch hook of hinge pin latch.

Remove hinge pin latch and cover hinge pin.

operating rod assembly

hinge pin

latch

cover hinge

bolt assembly

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MK 43 MOD 0

2. Grasp the flat spring on the right side of the grip assembly and pull the latch from

Trigger Mechanism Grip Assembly

the front pin.

3. Slide the slotted end of the spring from the grooved pin.

1. Use cleaning rod or similar item to push the latch in the head of the front pin to

disengage it.

CAUTION: Do not use tip of driving spring guide assembly as a tool.

grooved pin

grip

assembly

latch

assembly

flat

spring

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MK 43 MOD 0

4. Push out front pin.

Forearm Grip, Sling Swivel, and Bipod Assembly

5. Slide trigger mechanism grip assembly forward and pull out.

forearm

1. Insert the end of the punch in the grip access

grip ring

hole and push down on the spring detent.

2. Slide the forearm grip, sling swivel and bipod

assembly forward.

guide

CAUTION: Do not use tip of driving spring

tube

guide assembly as a tool.

front

trigger mechanism

Spring

grip assembly

detent

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MK 43 MOD 0

3. Remove forearm grip assembly, sling swivel

section IV. Cleaning and Inspection

and bipod assembly from the guide tube.

Bolt Assembly and Operating Rod Assembly

4. Separate sling swivel and bipod assembly

from the forward grip ring of the forearm grip

Inspect and Clean Bolt Assembly

assembly.

I. Inspect bolt assembly for burrs and cracks.

2. Make sure roller operates freely and is not cracked.

NOTE: Rotate cam actuator assembly so holes line up with headless straight pin.

Use reamer of combination wrench to remove or replace headless straight pin.

3. Remove headless straight pin and unscrew bolt plug assembly. Remove cam

actuator assembly from breech bolt. Separate spring, guide, and firing pin.

4. Make sure spring is not kinked.

5. Inspect threads on bolt plug assembly and in breech bolt for damage.

6. Clean powder fouling, corrosion, and dirt from all parts.

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MK 43 MOD 0

yoke

operating rod

cam

firing pin

roller

spring

guide

actuator

roller

sear notch

pins

operating rod drive

headless

bold plug

spring

straight pin

drive spring guide

assembly

bolt assembly

fluted carbon remover

NOTE: Use fluted carbon remover to clean inside of receiver (p 81).

7. Drop firing pin into breech bolt. Assemble and drop spring and guide into breech bolt.

Inspect and Clean Operating Rod Assembly

8. Assemble cam actuator assembly on breech bolt with roller to front. Screw in bolt

plug assembly and align three holes. Insert headless straight pin. Make sure cam

1. Inspect operating rod, yoke, sear notch, pins, and drive spring guide for burrs,

actuator assembly rotates freely when headless straight pin is fully seated.

cracks and chips.

2. Inspect operating rod drive spring for tension, kinks, breaks and wear.

3. Make sure roller operates freely.

4. Clean power fouling, corrosion, and dirt from all parts.

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MK 43 MOD 0

Inspect and Clean Cartridge Feed Tray Assembly

Cover Assembly and Cartridge Feed Tray Assembly

1. Inspect for burred, cracked, missing, or loose parts.

Inspect and Clean Cover Assembly

2. Check that feed tray fits on receiver and that feed pawl works properly and rollers

turn freely.

1. Inspect cover assembly for bent, burred, cracked, loose, or missing parts.

3. Clean corrosion and dirt from all areas.

2. Check spring action of front and rear guides, feed pawls (beneath the cartridge

guides), and feed cam assembly.

4. Remove lubricant from top surfaces of feed tray if gun is to be fired.

3. Make sure feed cam assembly is secure and operates freely.

4. Clean powder fouling corrosion, and dirt from all areas.

cartridge feed

tray assembly

rear cartridge

guide

front cartridge

guide

feed cam

feed pawl

cover assembly

US ORDNANCE

MK 43 MOD 0

Barrel and Handle Assembly

WARNING: Barrels issued for a specific gun should not be changed from gun to

gun. Each barrel and bolt assembly should remain together as Initially issued.

Inspect Barrel

4. To clean barrel, keep barrel and handle assembly upside down to keep gas

1. Check for burrs, cracks and wear especially in the barrel socket area.

system dry.

2. Make sure sight and flash suppressor are tight.

5. Run a clean rod with swab (item 5, app D) saturated with lubricant through bore.

3. Make sure handle is secure but turns freely.

Leave bore wet.

sight

handle

cleaning

rod

gas cylinder

swab

socket

barrel

gas cylinder

flash

extension assembly

suppressor

US ORDNANCE

MK 43 MOD 0

Inspect and Clean Gas System

2. Disassemble gas cylinder extension assembly with combination wrench. If gas

cylinder extension assembly is difficult to move, add a drop of lubricant where the

NOTE: Gas piston clicks when barrel is tilted. Take gas system (gas cylinder)

two protrusions contact the serrated lock nut and try again.

apart only when you don’t hear a click.

3. Clean extension vent hole with safety wire.

1. Use combination wrench and clean swab item 5, app D) to clean powder fouling,

corrosion, and dirt from alI parts.

gas cylinder

gas piston

extension assembly

combination

wrench

US ORDNANCE

MK 43 MOD 0

CAUTION: Insert reamer carefully to prevent damage.

Trigger Mechanism Grip Assembly

4. Clean gas port, gas piston holes, and gas cylinder vent hole with reamer portion

Inspect and Clean Trigger Mechanism Grip Assembly

of wrench.

5. Bottom the reamer in the gas port to make sure you have removed all carbon.

sear

Run small arms cleaning brush (bore) through bore to remove carbon deposits.

CAUTION: Do not get lubricant in gas system.

sear

plunger

6. Reassemble gas system (gas cylinder).

spring

trigger

7. Tighten gas cylinder extension assembly with wrench. Do not over-tighten. Then

sear pin

loosen the gas cylinder extension assembly 2 or 3 clicks.

combination

wrench

reamer

1. Hold down on sear and remove sear pin.

2. Remove sear, sear plunger and spring.

trigger

3. Remove trigger pin and trigger.

4. Clean powder fouling, corrosion,

and dirt from all areas.

US ORDNANCE

MK 43 MOD 0

5. Inspect sear for chips, cracks, and signs of wear.

Receiver

6. Inspect sear plunger and spring for signs of wear.

7. Position trigger in grip. Align holes and insert trigger pin through the right side of

Inspect and Clean Receiver

grip and secure trigger.

1. Clean powder fouling, corrosion, and dirt from all areas.

8. Insert spring and sear plunger into hole. Position sear and apply slight pressure to

2. When weapon is disassembled, use fluted end of operating rod assembly to

align holes. Insert sear pin through left side of grip and secure sear.

remove carbon from (operating rod) guide tube.

9. Check safety:

3. Check receiver rails for burrs and wear.

• F-Sear moves freely.

4. Check that cocking handle moves freely.

• S-Sear moves slightly.

guide

fluted carbon

operating rod

tube

remover

US ORDNANCE

MK 43 MOD 0

section V. reassembling machine gun

forearm

grip ring

Forearm Grip, Sling Swivel and Bipod Assembly

1. Position forearm grip under the

guide tube of assembly. Push

guide

assembly upwards over the

tube

guide tube and slide the assembly

guide

rearward until the forearm tabs

tube

engage the receiver grooves.

2. Position sling swivel and

bipod assembly in line with

forward grip ring.

3. Slide forearm grip assembly,

4. Depress spring detent with punch or

sling swivel and bipod assembly

receiver

forearm grip

Spring

suitable tool.

onto guide tube end.

assembly

detent

5. Slide forearm grip ring onto guide tube

until spring detent aligns/engages

bipod assembly

with hole in guide tube. Verify that all

components are secured.

US ORDNANCE

MK 43 MOD 0

Trigger Mechanism Grip Assembly

grooved pin

1. Position trigger mechanism grip assembly in bottom slot of receiver.

2. Align holes and install front pin. Position the flat on the head of the pin parallel with

the gun receiver so it fully enters the hole.

grip

assembly

latch

assembly

flat

spring

flat head

front pin

3. Hold latch assembly with latch pointed towards the front of the grip assembly. Slide

slotted end of flat spring onto grooved pin in the grip assembly.

trigger mechanism

4. Align latch pin with the hollow front pin and push it into the pin until the hook snaps

grip assembly

into position.

5. Verify that the latch is secured.

US ORDNANCE

MK 43 MOD 0

Barrel and Handle Assembly

Cover and Cartridge Feed Tray Assembly

1. Make sure barrel lock lever is up (unlocked).

1. Position cartridge feed tray

2. Install barrel and handle assembly.

assembly on receiver assembly.

3. Push barrel lock down (locked).

2. Install torsion spring in cover.

cover

Make sure that ends of torsion

spring are inserted in holes of

cover and receiver.

barrel and handle

torsion

barrel lock

assembly

spring

lever

cartridge feed tray

receiver assembly

US ORDNANCE

MK 43 MOD 0

Bolt Assembly and Operating Rod Assembly

hinge pin

latch

operating rod assembly

cover

hinge pin

3. Apply slight pressure to line up

torsion .spring and insert cover

bolt assembly

hinge pin. Install hinge pin latch

through hinge pin until it locks.

1. Place tower of operating assembly against spool of firing pin in slot of bolt assembly

Keep cover assembly open until

and push spool forward.

machine gun is reassembled.

2. Seat tower between spools of firing pin. Let tower slide back in bolt assembly.

US ORDNANCE

MK 43 MOD 0

3. Start operating rod assembly with bolt assembly into weapon. Turn bolt assembly

so that stripping lugs line up with upper rails. Push in until stripping lugs engage rails.

roller

breech

bolt

stripping lugs

operating rod

assembly

receiver

receptor

4. Turn roller straight up and push bolt

assembly and operating rod assembly

rails

as a unit into weapon.

5. Move safety to F. Pull back on trigger and hold.

trigger

Push breech bolt into receiver until it locks in place.

US ORDNANCE

MK 43 MOD 0

Shoulder Buttstock and Buffer Assembly

Assembly of Buttstock to Receiver

1. Install the buffer assembly into the buttstock as shown.

1. Install the drive spring and the drive spring guide into the receiver.

2. Align the drive spring guide with the buffer assembly.

3. Slide the buttstock onto the end of the receiver.

shoulder

buttstock

buffer

assembly

buffer

receiver

drive

assembly

spring

drive spring

guide

shoulder

buttstock

US ORDNANCE

MK 43 MOD 0

4. Push the buttstock forward as shown and install the yoke.

section VI. Maintenance Checklist

5. Close cover.

6. Manually cycle weapon system to ensure proper function.

Check the cleanliness and overall condition of the following:

1. Barrel assemblies. Chamber, bore and flash suppressor, gas cylinder, gas port, and

gas piston.

2. Receiver assembly. Operating rod guide, rails, and rear bridge rivets.

retaining

3. Bolt assembly.

yoke

4. Front and rear sights.

5. Shoulder buttstock.

6. Bipod assembly.

7. Trigger mechanism grip assembly.

8. Cocking handle assembly.

9. Cover assembly and cartridge feed tray assembly.

10. Blank firing attachment (BFA). Clean after firing 500 rounds or after each day’s

firing, whichever comes first. Remember BFA causes carbon fouling.

US ORDNANCE

MK 43 MOD 0

section VII. machine gun check out procedure

WARNING: After unloading dummyround, be sure the barrel is cleared.

7. Move safety to S.

Bolt Assembly Rearward? Good. Safety in S? Good.

8. Unload dummy ammunition and clear weapon (p 26).

1. Point weapon down range.

9. Verify that the projectile stayed with the dummy cartridge case.

2. Load machine gun with dummy ammunition (p 24).

10. Close cover and latch.

3. Squeeze trigger. Nothing should happen.

11. Move safety to F. Pull cocking handle, squeeze trigger and ease bolt assembly

4. Move safe to F.

forward.

5. Squeeze trigger. Bolt assembly should move forward, strip and chamber a dummy

round, and lock.

6. Pull cocking handle back. Dummy round should eject, and bolt assembly should

lock to rear.

US ORDNANCE

MK 43 MOD 0

Care, Handling, and Preservation.

chapter 4 - ammunition

a. Do not open ammunition containers until the ammunition is to be used. Ammunition

removed from the airtight containers, particularly in damp climates, is likely to corrode.

b. Protect ammunition from mud, dirt and water. If the ammunition gets wet or dirty,

wipe it off prior to use. Wipe off light corrosion as soon as it is discovered. Heavily

WARNING: This is the only ammunition authorized for use in your machine gun.

corroded cartridges or cartridges which have dented cases or loose projectiles should

If it is not shown, it is not authorized.

not be fired.

c. Do not expose ammunition to the direct rays of the sun. If the powder is hot,

black

4-1 combat

red or

excessive pressure may be developed when the gun is fired.

mix

orange

d. Do not oil or grease ammunition. Dust and other abrasives collecting on oiled or

greased ammunition will damage the operating parts of the gun.

Ammunition Which Fails To Fire.

Dispose of any ammunition, which fails to fire, according to authorized procedures.

armor

ball

tracer

dummy

blank

piercing

US ORDNANCE

MK 43 MOD 0

Forms

appendix a

DA Form 2028 -Recommended Changes to Publications and Blank Forms SF 368 -

Quality Deficiency Report

references

Technical Manuals.

TM 02705E-IO/l- Operators Manual for Machine Gun, 7.62 MM, M60E3 and Mount,

Tripod, Machine Gun, 7.62MM, M122.

Scope.

This appendix lists some manuals referenced in this manual, and some other sources

TM 3-220 - Chemical, Biological and Radiological (CBR) Decontamination

of information about M60 machine guns and ancillary equipment.

TM 11-5855-213-10 -Operators Manual for Night Vision Sight, Individual Served

Field Manuals.

Weapon, AN/PVS4

Machine gun 7.62-MM, M60 -- FM 23-67

Firing Table.

FT 7.62-A-2

Machine Gun, 7.62-mm; M60 on Mount, Machine Gun: 7.62-mm, Ml22 and Machine

Gun, 7.62-mm: M73 on Tank, Combat, Full-Tracked: 105-mm Gun, M60 Series and

Rifle, 7.62mm: M14; Firing Cartridge, 7.62mm, Ball, NATO, M59; Cartridge, 7.62mm,

Ball, NATO, M80; Cartridge, 7.62mm: AP, NATO, M61 and Cartridge, 7.62mm: Tracer,

NATO, M62.

US ORDNANCE

MK 43 MOD 0

Although shipped separately packaged, BII must be with the MK43 Mod0 machine

appendix b

gun during operation and whenever it is transferred between property accounts. The

illustrations will assist you with hard-to-identify items. This manual is your authority to

section I. Introduction

request/requisition replacement BII, based on approved allowance for the end item.

Explanation of Columns

Scope.

The following provides an explanation of columns found in the tabular listings:

This appendix lists components of end item and basic issue items for the MK43 MOD

a. Column (I) - Illustration Number. This column indicates the number of the illustration

0 machine gun to help you inventory items required for safe and efficient operation.

in which the item is shown.

General.

b. Column (2) - National Stock Number. Indicates the National stock number assigned

The Components of End Item and Basic Issue Items Lists are divided into the

to the item and will be used for requisitioning purposes.

following sections:

c. Column (3) - Description. Indicates the Federal item name and, if required, a

a. Section II. Components of End Item. This listing is for informational purposes only

minimum description to identify and locate the item. The last line for each item

and is not authority to requisition replacements. These items are part of the end

indicates the Contractor and Government Entity Code (CAGEC) (in parentheses)

item but are removed and separately packaged for transportation or shipment. As

followed by the part number.

part of the end item, these items must be with the end item whenever it is issued

d. Column (4) - Unit of Measure (U/M). Indicates the measure used in performing

or transferred between property accounts. Illustrations are furnished to assist you

the actual operational/maintenance function. This measure is expressed by a two-

identifying the items.

character alphabetical abbreviation (e.e., ea., in., pr.).

b. Section III. Basic Issue Items. These are the minimum essential items required

e. Column (5) - Quantity required. Indicates the quantity of the item authorized to be

to place the MK43MOD0 machine gun in operation, to operate it, and to perform

used with/on the equipment.

emergency repairs.

100

US ORDNANCE

MK 43 MOD 0

101

section III. basic issue items

(1)

(2)

(3)

(4)

(5)

Illustration

National

Description

U/M

Quantity

Number

Stock Number

CAGEC & Part Number

Required

1005-01-184-6362

Barrel and carrying

handle assembly (26978)

MD3521

1005-01-791-5420

Carrying case for barrel

assembly and equipment

(19205) 7791009

4933-00-652-9950

Extractor for ruptured

cartridge case (19205)

7790352

5120-00-461-1075

Wrench, screwdriver, and

reamer (combination)

(19204) 8448458

0640-LP-544-4800

TM, Operators Manual

SW-370-AJ-OPII-010/

M43 MOD 0

104

US ORDNANCE

MK 43 MOD 0

105

section II. additional authorized list

appendix c - additional authorized list

section I. Introduction

(1)

(2)

(3)

(4)

National

Description

U/M

Quantity

Stock Number

FSCM & Part Number

Required

Scope.

The appendix lists additional items you are authorized for the support of the MK43

1005-00-140-3515

Firing attachment, blank:

MOD0 Machine Gun.

(19204) 12002981

1005-00-556-4174

Brush, cleaning, small arms:

General.

(bore) (19204) 5564174

This list identifies items that do not have to accompany the MK43 MOD 0 Machine

Gun and that do not have to be turned in with it.

1005-00-690-3115

Brush, cleaning, small arms:

(chamber) (19204) 7790452

Explanation of Listing.

National stock numbers, descriptions, and quantities are provided to help you identify

1005-00-350-4100

Brush, cleaning, small arms:

and request the additional items you require to support this equipment.

(receiver) (19204) 8448466

Bore

chamber

receiver

Brush

brush

108

US ORDNANCE

MK 43 MOD 0

109

c. Column (3) - National Stock Number. This is the National stock number

appendix d - expendable supplies

assigned to the item; use to request or requisition the item.

d. Column (4) - Description. Indicates the Federal item name and, if required, a

section I. Introduction

description to identify item. The last line for each item indicates the Contractor and

Government Entity Code (CAGEC) in parentheses followed by the part number.

e. Column (5) - Unit of Measure (U/M). Indicates the measure used in performing

Scope.

the actual maintenance function. This measure is expressed by a two-character

This appendix lists expandable su plies and materials you will need to operate and

alphabetical abbreviation (e.g., ea., in., pr.). If the unit of measure differs from the

maintain the MK43 M 8 D 0 Machine Gun.

unit of issue, requisition the lowest unit of issue that will satisfy your requirements.

Explanation of Columns.

a. Column (1) - Item Number (Item Number). This number is assigned to the entry in

the listing and is referenced in the narrative instructions to identify the material

(e.g., “Use wiping rag, item 4, app D).

b. Column (2) - Level. This column identifies the lowest level of maintenance that

requires the listed item.

110

US ORDNANCE

MK 43 MOD 0

111

section II. expendable/durable supplies and materials list

(1)

(2)

(3)

(4)

(5)

Item

Level

National Stock

Description

U/M

Number

CAGEC & Part Number

9150-01-102-1473

Cleaner, lubricant and

preservative (CLP) 1/2 oz.

bottle (81349) MIL-L-63460

9150-00-753-4686

Lubricating Oil (LSA)

9150-00-292-9689

Lubricating Oil (LAW)

7920-00-205-1711

RAG WIPING: (cotton) 50lb.

bdl. (81348) a-a-531

1005-00-288-3565

Swab, small arms cleaning

(cotton) 2 1/2 in. sq. (1000

per pkg.) (19204) 5019316

112

US ORDNANCE