M249 MACHINEGUN

SUBCOURSE OD1505

EDITION 7

MAINTENANCE OF THE M249 MACHINEGUN

US ARMY TANK TURRET REPAIRER CORRESPONDENCE COURSE MOS/SKILL LEVEL: 45K30 MAINTENANCE OF THE M249 MACHINEGUN SUBCOURSE NO. OD1505 US Army Correspondence Course Program 6 Credit Hours GENERAL The The purp purpos ose e of this this subc subcou ours rse e is to incr increa ease se know knowle ledg dge e of the the operation of the M249 machinegun and the maintenance and inspection procedures needed to maintain the machinegun at the operator, unit, and intermediate direct support (IDS) maintenance levels. Six Six cred credit it hour hours s are are awar awarde ded d for for succ succes essf sful ul comp comple leti tion on of subcourse. It consists of one lesson of two tasks as follows:

this this

Lesson 1:

M249

OPERATION, MACHINEGUN

MAINTENANCE,

AND

INSPECTION

OF

THE

TASK 1: Describe the operation of the M249 machinegun. TASK 2: Describe Describe operator, unit, and intermediate intermediate direct support support (IDS (IDS) ) main mainte tena nanc nce, e, and and insp inspec ecti tion on proc proced edur ures es for for the the M249 M249 machinegun.

i

M249 MG MAINTENANCE - OD1505

TABLE OF CONTENTS

Section

Page

TITLE................ .......... ....... ...... .... ... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .

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TABL TABLE E OF CONT CONTEN ENTS TS .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..

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Lesson Lesson 1: OPERAT OPERATION ION, , MAINTEN MAINTENANC ANCE, E, AND INSPECTION OF OF TH THE M2 M249 MA MACHINEGUN...................

1

Task 1: Describe the operation of the M249 machinegun..........................................

1

Task 2: Describe operator, unit, and intermediate direct support (IDS) maintenance, and inspection procedures for the the M24 M249 mac machinegun. un.... ....... ...... .... ... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .

16

Pra Practical Exe Exercise 1... 1..... .... .... .... ... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .

56

Ans Answers to to Pr Practical cal Ex Exercise 1. 1..... ..... ..... ..... ..... ...... .... .... .... .... ... .

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REFE REFERE RENC NCES ES.. .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..

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*** IMPORTANT NOTICE ***

THE PASSING SCORE FOR ALL ACCP MATERIAL IS NOW 70%. PLEASE DISREGARD ALL REFERENCES TO THE 75% REQUIREMENT.

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THIS PAGE INTENTIONALLY LEFT BLANK

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STUDENT NOTES

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M249 MG MAINTENANCE - OD1505 - LESSON 1/TASK 1

LESSON 1 OPERATION, MAINTENANCE, AND INSPECTION OF THE M249 MACHINEGUN

TASK TASK 1. 1.

Desc Descri ribe be the the ope opera rati tion on of of the the M249 M249 mac machi hine negu gun. n.

CONDITIONS Within a self-study self-study environment and given the subcourse text, without assistance.

STANDARDS Within two hours

REFERENCES No supplementary references are needed for this task.

1.

Introduction

The M249 machinegun is designed as a fire team automatic weapon to be used for for rear area area security security and and special special missions. missions. The machinegun machinegun is gas operated, operated, air-cooled, air-cooled, and and fires fires from the the open bolt position position. . It has a regulator for selecting normal or maximum (max) rate of fire. Use of the max rate is authorized authorized only in the event that the weapon's firi firing ng rate rate slow slows s down down, , othe otherw rwis ise e stat stated ed: : the the weap weapon on beco become mes s slug sluggis gish. h. It also also has an alte altern rnat ativ ive e 30 round round maga magazi zine ne feedi feeding ng provision. The use of the 30 round magazine is authorized only in an emer emerge genc ncy y situ situat atio ion n sinc since e the the use use of the the maga magazi zine ne redu reduce ces s the the performance of the machinegun. This task will describe the major components and equipment data of the M249 machinegun and the operation of the M249 machinegun under usual and unusual conditions.

2.

Major Major Comp Compon onen ents ts and Equi Equipm pmen ent t Dat Data a of of the the M249 M249 Machi Machine negu gun n 1


FIGURE 1.

a.

LOCATION OF THE MAJOR COMPONENTS OF THE M249 MACHINEGUN.

The majo major r com compo pone nents nts of the the mac machi hineg negun un (sho (shown wn in figur figure e 1) 1) are are: :

(1) Barr Barrel el Assem Assembl bly y . Hous Houses es car cartr trid idge ge projectile, and supports fixed front sight. (2) Rear Rear Sigh Sight t Asse Assembl mbly y . windage and elevation.

Rear Rear

sig sight ht

is is

for for

fir firin ing, g,

adju adjust stab able le

dir direc ects ts

for for

bot both h

(3) Cover/ Cover/Feed Feed Mechan Mechanism ism Assemb Assembly ly . Prov Provid ides es supp suppor ort t for for rear rear sight and and means means for gaining gaining access access to to feed tray. tray. By means means of cam and lever action, feeds linked belt ammo and holds cartridges cartridges in position position for stripping, feeding, and chambering. Feed Pawl Pawl Assemb Assembly ly (4) Feed . Feeds Feeds link linked ed bel belt t ammo ammo, , posi positi tion ons s and and holds cartridges in position for stripping, feeding, and chambering.

(5) Cockin Cocking g Handle Handle Assemb Assembly ly . Pull Pulls s the the mov moving ing part parts s rea rearw rwar ard. d. Moves in a guide rail fixed to the right side of the receiver. 2


(6) Butt Butt Stoc Stock k and and Shou Should lder er Assem Assembl bly y . Serv Serves es as a shou should lder er support support for for aiming aiming and and firing firing the machin machinegu egun. n. Contain Contains s a folding folding shoulder rest. (7) Piston Assembly Assembly . Tran Transf sfers ers pow power er from from prop propel elli ling ng gases gases to to bolt bolt and and slid slide e assem assembl blie ies s as well well as to move move the recoi recoili ling ng part parts s rearward. (8) Bolt Bolt Asse Assemb mbly ly . Prov Provid ides es feed feedin ing, g, stri stripp ppin ing, g, cham chambe beri ring ng, , firing, and extraction, using the propellant gases and recoil spring for power. (9) Slide Assembly .

Houses firing pin and roller assembly.

(10) Rod Buffer and Spring Assembly . Absorbs recoil from bolt and operating rod assembly at the end of recoil movement. (11) Receiv Receiver er Assemb Assembly ly . Serves as a support for all all maj major compone components nts. . Houses Houses actio action n of weapon weapon and, and, throug through h a series series of cam ways, controls functioning of weapon. Trigger r (12) Trigge machinegun.

Mechan Mechanism ism

Assemb Assembly ly .

Controls

the the

firing

of

the

(13) Guard Assembly Assembly . Provid Provides es therm thermal al insul insulati ation on to to protec protect t the the operator's hands from heat, and houses cleaning equipment. (14) Bipod Machinegun Machinegun. Support Supports s machi machineg negun un in in prone prone and sittin sitting g position. position. The telescopic telescopic legs can can be individu individually ally adjusted adjusted to three three different lengths. (15) Gas Cylinder Assembly . Locks Locks bipo bipod d in place place on on receiv receiver er and and provides passage-way for operating gases. b. Equipment Data. following page.

The equipme equipment nt data data is listed in Table Table 1 on the the

3


TABLE 1.

EQUIPMENT DATA ON THE M249 MACHINEGUN.

°

°

*Cyclic rated at 70 F (21 C) when set at MAX position. 3.

Ope Operation of of th the M2 M249 Ma Machinegun

a. General. The barr barrel el of the M249 M249 mach machine inegun gun is is air-co air-coole oled d and has a fixed fixed head head space. space. Gas is taken taken from from the the barrel barrel acting acting on a piston directly directly fixed to the bolt bolt carrier carrier (slide). (slide). The gas pressure pressure is controlled by a two position regulator; one for normal conditions and the other for delivering additional power for adverse conditions (see figure figure 2 on the following following page). page). The regulator regulator is based based on the the gas exhaust system. The bolt is a multiple4


lug type which rotates into a positive locked position in the barrel extension prior to firing. NOTE

MAX position to be used ONLY when the weapon will not not func functi tion on prop proper erly ly in the the NORM NORMAL AL posi positi tion on (i.e., sluggish operation).

FIGURE 2.

CONTROL OF GAS PRESSURE BY TWO POSITION REGULATOR.

b. Operati Operation on Under Under Usual Usual Conditi Conditions ons. There There are seven seven proced procedure ures s that that are are used used when when oper operat atin ing g the the M249 M249 mach machin ineg egun un unde under r usua usual l cond condit itio ions ns. . Thes These e proc proced edur ures es are are desc descri ribe bed d in the the foll follow owin ing g subparagraphs: (1) Loading . To load load the mach machine inegun gun, , be sure sure the palm palm is up up and then then pull pull the the cock cockin ing g hand handle le to the the rear rear to lock lock the the bolt bolt; ; this this action will charge the weapon. Push the cocking handle forward until a click is heard and then push the safety to the right so that the red ring ring is not visib visible, le, (SAFE (SAFE). ). Now, Now, squeeze squeeze the the latches latches to open open the cover assembly (see figure 3 on the following page). 5


Then Then, , rais raise e the the feed feed tray tray and and look look into into the the cham chambe ber r to make make sure sure there there is no round round chambe chambered. red. If no round round is chambe chambered red, , lower lower feed tray tray (figu (figure re 4). If round round was chamb chamber ered ed, , the the stuc stuck k cart cartri ridg dge e procedures found in paragraph 3b(6) on page 12 of this task would be performed.

FIGURE 3.

FIGURE 4.

6

OPENING COVER ASSEMBLY.

LOOKING FOR CHAMBERED ROUND.


Atta Attach ch the the 200 200 roun round d ammo ammo box box cont contai aini ning ng the the link link belt belt to the the unde unders rsid ide e of the the rece receiv iver er afte after r alig aligni ning ng the the box box latc latch h with with the the receiver dovetail (see figure 5). NOTE

Open side of links are down. Now, Now, plac place e the the link link belt belt in the the feed feed tray tray with with the the firs first t roun round d against the cartridge stop, hold the belt in position, and close the cover assembly assembly (see (see figure figure 6 on the the following following page). The cartridge cartridge indicator should protrude approximately 13mm or one-half inch above the top of the cover if the ammo belt is properly positioned against the cartridge stop.

FIGURE 5.

ATTACHING 200-ROUND AMMO BOX.

If link link belt belt is proper properly ly positi positioned oned, , the cartri cartridge dge indica indicator tor will will stick up above the top of the left side of the cover (see figure 7 on the following page). (2) Clearing . To begin begin clearing clearing the weapon, charge the weapon weapon by pulling the cocking cocking handle handle to the rear. Be sure the bolt bolt is locked locked in the rear position and then push the charging handle forward until a click is heard. heard. Push safety safety to to the right right so that the the red ring ring is not visible (SAFE) (see figure 8 on page 9). 7


FIGURE 6.

FIGURE 7.

8

PLACING LINK BELT IN FEED TRAY.

POSITION OF CARTRIDGE INDICATOR.


FIGURE 8.

CHARGING THE M249 MACHINEGUN.

If the belt feed is being used, squeeze squeeze the latches to open the cover asse assembl mbly. y. Then Then, , remove remove the ammo ammo belt belt and loos loosen en the link links s (see figure 9 on the following page). Now, raise raise the feed tray tray and look into into the chamber. chamber. If the round round is is still chambered, remove the round as discussed in paragraph 3b(6) on page page 12 of this this task. task. If the chamb chamber er is empty empty, , lower lower the feed feed tray tray and and close close the cover cover assemb assembly ly. . Make Make sure that that the cover cover assemb assembly ly locks shut. Push the safety to the left so that the red ring is visible (FIRE) and hold the cocking handle to the rear, while depressing the trigger and riding the bolt forward to close and lock. (3) Field Zero. When field zeroing the machinegun, the first step is to center center the the rear sight sight. . This is is done by rota rotating ting the the windag windage e knob, which is the front knob on the rear sight, until the peep sight is completely completely to the right. Then rotate rotate the windage windage knob backwar backwards ds 12 clicks (see figure 10 on the following page).

9


FIGURE 9.

CLEARING M249 MACHINEGUN WHEN USING BELT FEED.

FIGURE 10.

10

FIELD ZEROING THE M249 MACHINEGUN.


Each sight may vary as to how many clicks are needed to center the sight. sight. To check check the sight sight, , start start with the the sight sight all the way way to the right, rotate the windage knob backwards until it stops on the left side - count the clicks - divide this number by two - example: 24 clicks = 12 to center; example: 23 clicks = 12 to center (11 + 12 = 23, use larger figure). Now, rotate the elevation elevation knob to the desired range and fire a 3 to 5 round burst burst on on the center center of the target. target. At this this time, fine windage windage adjustm adjustment ents s may be needed needed. . When makin making g the fine fine windage windage chang changes, es, rotating the windage knob forward will move the impact to the right, and rotating the windage knob backward will move impact to the left. Each Each clic click k of the the wind windag age e knob knob equa equals ls a 1/2 1/2 mil mil whic which h move moves s the the impact a 1/2 meter meter at a 1000 meters. To change change the elevation elevation of the impact, rotate the elevation knob clockwise to lower the impact or rotate the elevation knob counterclockwise to raise the impact. Each click of the ele elevation knob equ equals a 1/2 mil change in elevati elevation. on. To make make the elevat elevation ion knob knob easier easier to grasp grasp, , rotate rotate the elevati elevation on knob knob to the 1000 1000 meter meter (m) mark. mark. After After making making the the fine adjustment, move the elevation knob back to the start position. (4) Immediate Action. If the weapon stops firing with the trigger depress depressed, ed, immedi immediate ate actio action n must be taken taken. . Charge Charge the weapo weapon n and push the cocking handle forward until a click is heard. If the round is ejected - FIRE AGAIN! WARNING

If nothing is ejected and the barrel is hot (200 roun rounds ds fire fired d with within in a 2 minu minute te peri period od), ), do not not open the cover. cover. Push safety safety to the right so that that the the red red ring ring is is not not visib visible le (SA (SAFE) FE). . Keep Keep the the mach machin ineg egun un poin pointed ted down downra rang nge, e, and and rema remain in clear clear for for 15 minu minute tes. s. Afte After r 15 minu minute tes, s, clea clear r the mach machin ineg egun un as desc descri ribe bed d in para paragr grap aph h 3b(2 3b(2) ) on page 7 of this task.

11


If nothing is ejected, and belted ammo is being used, look to see if the cartridge cartridge indicator indicator is in the lower (down) position. position. If it is, is, and no rounds remain on the feed tray, you have run out of belted ammo ammo. . If the cart cartri ridg dge e indica indicato tor r is in the up posit positio ion n and the the barrel is not hot, clear clear the the weapon. weapon. If nothing nothing is ejected and the alternate magazine feed is being used, and barrel is not hot, clear the weapon. (5) If Imme Immedi diat ate e Actio Action n Doesn Doesn't 't Work Work. Be sure sure the the weap weapon on is cleared and then check for dirt, proper lubrication, lubrication, and obstructions obstructions under the feed tray. Reload and fire again. (6) Stuck Cartridge Case or Live Round . WARNING

Stay clear of muzzle. muzzle. Do not not allow allow round to hit hit any hard hard surface surface or it may fire. fire. Dispose Dispose of live round in accordance with local regulations. If round round fired fired but did did not extract, extract, the cartridge cartridge case case is stuck. stuck. If round round did not not fire and and did not extr extract, act, a live live round round is stuck. stuck. To begin removal of either the cartridge case or live-round, charge the weapon and push the safety to left so that the red ring is visible, (FIRE). Now, pull pull the trigger. trigger. If the round still doesn't doesn't fire, wait until until the barre barrel l is cool, cool, which which is approxi approximat mately ely 15 minut minutes. es. Charge Charge the the weap weapon, on, plac place e the safety safety on safe and and remove remove the barre barrel. l. Remo Remova val l procedures procedures for the barrel are found in paragraph 20 of task 2 on page 20 of this subcourse. Assemble the cleaning rod without the swab holder and insert the rod through the muzzle muzzle end end of the the barrel. barrel. Then gently gently tap tap out the case case or round (see figure 11 on the following page). (7) Runaway Machinegun. A runaway runaway machinegun machinegun can be described described as a machinegun machinegun that that won't won't stop firing. firing. If runaway runaway occurs, occurs, take take action action to correct it quickly. WARNING

Always keep machinegun pointed downrange. 12


FIGURE 11.

REMOVING A STUCK ROUND.

Take either of the following actions: (a) (a) Let Let the machi machine negu gun n fire if it is near near the the end of the link link belt or magazine capacity, or (b) (b) Grab Grab the cocki cocking ng handl handle e (pal (palm m up), up), and pull pull all the way way back back and hold hold. . Push Push safet safety y to the right right (red (red ring ring not visib visible le), ), raise cover, and remove the link belt or magazine (see figure 12 on the following page). Notify unit maintenance for necessary repairs. WARNING

Neve Never r relo reload ad a runa runawa way y mach machin ineg egun un unti until l it repaired. Be sure the machinegun is cleared.

is

c. Operation Under Unusual Conditions. The only unusual unusual condition condition that is described in this paragraph is when a 30 round magazine is needed in an emergency situation. NOTE

Emer Emerge genc ncy y situ situat atio ion n not available.

exis exists ts when when

link linked ed ammo ammo is 13


FIGURE 12.

CORRECTIVE ACTION FOR RUNAWAY MACHINEGUN.

In an emer emerge genc ncy, y, the the 30 roun round d maga magazi zine ne may may be load loaded ed into into the the machinegun by inserting it into the magazine well, which is on the left side of the receiver. Now, push it firmly to the right until it bottoms in the well and the release tab “clicks" into the recess in the magazine (see view A in figure 13 on the following page). If the alternate (emergency) magazine feed is used, push down on the maga magazin zine e rele release ase tab, tab, pull pull out out used used magaz magazin ine, e, and and raise raise the the cove cover r assembly (see view B in figure 13).

14


FIGURE 13.

4.

LOADING A 30 ROUND MAGAZINE.

Conclusion

This This task task desc descri ribe bed d the the oper operat atio ion n of the the M249 M249 mach machin ineg egun un at the the operato operator's r's level. level. The next next task task will discu discuss ss the maint maintena enance nce and and insp inspect ectio ion n proc proced edur ures es for for the the M249 M249 mach machine inegu gun n at thre three e diff differ eren ent t leve levels ls of main mainte tena nanc nce: e: oper operat ator or, , unit unit, , and and inte interm rmed edia iate te dire direct ct support (IDS). 15


LESSON 1 OPERATION, MAINTENANCE, AND INSPECTION OF THE M249 MACHINEGUN

TASK TASK 2.

Desc Descri ribe be oper operat ator or, , unit unit, , and and inte interm rmed edia iate te dire direct ct supp suppor ort t (IDS) (IDS) mainte maintenan nance, ce, and inspec inspectio tion n proced procedure ures s for the M249 M249 machinegun.

CONDITIONS Within a self-study self-study environment and given the subcourse text, without assistance. STANDARDS Within three hours REFERENCES No supplementary references are needed for this task.

1.

Introduction

The The M249 M249 mach machin ineg egun un must must oper operat ate e prop proper erly ly when when used used for rear rear area area security security or when used used for for special special missions. missions. This task task will will provide provide examples of maintenance and inspection procedures needed to keep the mach machin ineg egun un oper operat atio iona nal. l. Thes These e proc proced edur ures es are are inte intend nded ed for for the the operato operator, r, unit unit mainte maintenan nance, ce, and interm intermedi ediate ate direct direct suppor support t (IDS) (IDS) maintenance. 2.

Fiel Field d Str Strip ippi ping ng the the M24 M249 9 Mac Machi hine negu gun n

a. General. To perform perform maintenan maintenance ce on the the M249 M249 machinegun, machinegun, it must be field field stripped stripped to make every every componen component t accessible. accessible. The following following paragraphs will supply the field stripping procedures. NOTE

Before executing these procedures, the machinegun must be cleared. 16


b.

Operating Rod Assembly Removal. WARNING

Be sure the bolt is in the before removing return spring.

forwa rward

positio tion

If the moving parts are situated at the rear, put safety on fire and hold the cocking handle with one hand. Press the trigger and let the moving parts come slowly forward. Raise the cover assembly and pull the upper retaining pin at the rear of receiver to the left. Let the butt pivot downward so that the rear opening on the receiver is completely free (see figure 14).

FIGURE 14.

FREEING REAR OPENING ON THE RECEIVER.

By holding the weapon with one hand on the butt stock, simultaneously push in and upward on the rear end of the operating rod assembly with the thumb of the other hand (see view A in figure 15 on the following page). The operating rod assembly should now release from the positioning groove groove insid inside e the receiv receiver. er. Withdra Withdraw w the operat operating ing rod rod assembl assembly, y, which consists 17


of the spring, the guide rod and the buffer, from the receiver.

FIGURE 15.

RELEASING AND WITHDRAWING OPERATING ROD ASSEMBLY.

Now, Now, slid slide e the the movi moving ng part parts s out out of the the rear rear of the the rece receiv iver er by pulling the cocking handle to the rear (see view B in figure 15). Rotate the bolt of the bolt carrier (slide) to disengage the lug and pull it out of the slide assembly (see view A in figure 16 on the next page). 18

M249 MG MAINTENANCE - OD1505 - LESSON 1/TASK 2 CAUTION

When the bolt is removed, the firing pin spring is free. Be careful not to lose it. To separate the slide assembly from the piston, press the retaining pin at the rear to the left and lift off the slide assembly (see view B in figure 16).

FIGURE 16.

REMOVAL OF SLIDE ASSEMBLY.

FIGURE 17.

REMOVAL OF BARREL.

19


c. Barrel Removal. Close Close the the cover cover and and depres depress s the locking locking lever lever of the barrel with the the left hand. Hold the the carrying carrying handle handle with with the right hand, lift it up and push the barrel forward (see figure 17 on the previous page). d. Gas Regulator Removal. Remove the barrel and then position position the gas regul regulato ator r lever lever between between NORMAL NORMAL and and MAX. MAX. Place Place the tip tip of the spring guide rod in the notch in the front left of the gas block (NORMAL position position of lever) and hold guide firmly in notch (see view A in figure 18).

FIGURE 18.

REMOVAL OF GAS REGULATOR.

Now, Now, hold holding ing the guide guide rod in posit positio ion, n, turn turn the the coll collar ar back back and and beyond the NORMAL position until the collar can be removed (see view B in figure 18). Note the position of the hand supporting the 20


gas gas regu regula lato tor. r. In this this posi positi tion on, , the the gas gas regu regula lato tor r can can now now be removed from the gas block as shown in view C of figure 18 on the previous page. e. Handguard Removal. Push the handguard handguard retaini retaining ng pin pin to the left left using the spring guide rod, then remove the handguard in a downward motion (see figure 19).

FIGURE 19.

REMOVAL OF HANDGUARD.

f. Butt Butt Stoc Stock k and and Shoul Shoulde der r Assem Assembl bly y Remov Removal al. Usin Using g the the spri spring ng guide rod, push the lower most retaining pin to the left. Remove the butt stoc tock and shoulder asse ssembly, pulling it rearward while supp support ortin ing g the the trig trigge ger r mech mechan anis ism m (see (see figur figure e 20 on the the foll follow owin ing g page). g. Trigger Mechanism Removal Removal. Remov Remove e the the trig trigger ger mecha mechani nism sm in in a downward motion (see figure 21 on the following page). h. Gas Cylinder Removal. the the righ right t to rele releas ase e the the figure 22 on page 23).

Turn Turn the the gas gas cylin cylinder der to the the left left or to to lock lockin ing g spri spring ng, , then then pull pull forw forwar ard d (see (see

i. Bipod Bipod Remova Removal l. After removing the gas cylinder der from the receiver, the bipod can then be removed (see figure 23 on page 23). 21


FIGURE 20.

REMOVAL OF BUTT STOCK AND SHOULDER ASSEMBLY.

FIGURE 21.

22

REMOVAL OF TRIGGER MECHANISM.


FIGURE 22.

REMOVAL OF GAS CYLINDER.

FIGURE 23.

REMOVAL OF BIPOD.

j. Preventive Maintenance Checks and Services (PMCS) (see figures 24A 24A and 24B on the the follow followin ing g pages pages). ). When When perfo perform rmin ing g the PMCS, PMCS, always keep in mind mind the CAUTIONS CAUTIONS and WARNINGS WARNINGS. . Also, the the numbers numbers in the item number column shall be used for the "TM number" column on DA Form Form 2404 2404, , Equi Equipm pmen ent t Insp Inspec ecti tion on and and Main Mainte tena nanc nce e Works Workshe heet et, , when when recording the results of the PMCS.

23


PMCS would be performed if: (1) you are the assigned operator operator and the machinegun has been stored and not used for a period of 90 days, or (2) you have been issued the machinegun for the first time.

FIGURE 24A.

24

PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS).


FIGURE 24B.

PREVENTIVE MAINTENANCE CHECKS AND SERVICES (CONTINUED).

3.

Oper Operat ator or/C /Cre rew w Main Mainte tena nanc nce e Proc Proced edur ures es

a.

Cleaning, Inspection, and Repair . WARNING

Using gasoline, kerosene, hydraulic oil, benzene, bensol, high-pressure water, steam, or compressed air for cleaning is prohibited. CAUTION

Do not use abrasives to clean the bore, piston, gas cylinder, or gas regulator plug. 25


(1) Cleaning Tools. The cleani cleaning ng tool tools s for for the the M249 M249 mach machine inegun gun are housed inside the handguard (see figure 25).

FIGURE 25.

26

CLEANING TOOLS AND LOCATION.


(2) Proc Proced edur ural al Machinegun.

Step Steps s

for for

Clea Cleani ning ng

Gene Genera ral l

Area Areas s

of

the the

M249 M249

CAUTION

Do not oil the gas regulator or the recess in the barrel for the gas regulator. Do not use abrasives to clean the gas regulator. Step 1.

Inspect the bore and chamber (see figure 26).

FIGURE 26.

CLEANING BORE AND CHAMBER.

Step 2. Wipe the outside of the barrel with a lightly oiled rag. If heavy bore and/or chamber deposits are present, clean the bore with a bore brush, and clean the chamber with a chamber brush. Step 3. Inspect Inspect for cracks, cracks, dents, burrs, or other other damage damage on flash flash hider, barrel extension, extension, and and barrel barrel release. release. Check front sight sight for looseness. If looseness is found, notify unit maintenance. Step 4. Check cover assembl assembly y for smooth operation, operation, spring spring tension, tension, bent parts, parts, or excessive excessive wear. wear. Lightly Lightly oil moving moving parts parts marked marked with with an "O" (see view A in figure 27 on the following page). Step Step 5. Chec Check k for for bend bends s and and crac cracks ks, , free free movem movemen ent t of cocki cocking ng asse assembl mbly, y, and excess excessiv ivel ely y worn worn, , burr burred ed, , or chippe chipped d rail rails. s. Chec Check k barrel barrel lockin locking g latch latch and cover cover detent detent springs springs for spring spring tensio tension. n. Lightly oil all rails (see view B in figure 27). 27


FIGURE 27.

LUBRICATION OF M249 MACHINEGUN.

Step 6. Check for for broken pistol grip, grip, and chipped chipped or cracked cracked trigger trigger housing holding lug. Step 7. wear. Step 8. 28

Check tripping tripping lever and and sear for burrs, burrs, cracks, cracks, chips, chips, and

Notify unit maintenance if problem exists.


Step 9. Check cocking action by: pushing back on tripping lever (the sear should raise), and pulling the trigger (the sear should lower). Now, push back on the tripping lever. Step 10. Check the the safety function function as follows: follows: when when safety is pushed pushed to the right, pull trigger (the sear should not lower); when safety is pushed to the left, pull trigger (the sear should lower). Step 11. Lightly lubricate tripping lever and sear surfaces, ends of trig trigge ger r pin, pin, safe safety ty shaf shaft, t, and and sear sear pivo pivot t pin pin area areas s whic which h are are highlighted by an "O” (see view C in figure 27 on the previous page). Step Step 12. Chec Check k bolt and oper operat ating ing rod rod for burrs, burrs, crack cracks, s, broke broken n pins, or or frozen frozen roller. roller. Push down down on the the roller roller to make make sure it it will retr retract act. . Check Check driv drivin ing g spri spring ng for for broke broken n stra strand nds. s. Noti Notify fy unit unit maintenance if more than one broken strand is found on the same coil or on the entire spring. NOTE

Do not not lubricate lubricate top or face face of bolt. Do not not oil piston. piston. Notify unit maintenance maintenance if heavy carbon deposits cannot be removed. Lightly Lightly oil drivin driving g spring spring, , bolts bolts and operati operating ng rod moving moving parts, parts, polished areas, firing pin, and roller designated by an "O” (see view D in figure 27). Step Step 13. Clea Clean n and and chec check k bipo bipod d legs legs for opera operati tion on and light lightly ly lubricate lubricate the areas where an "O" is shown (see view A in figure 28 on the following page). Notify unit maintenance if problem exists. Step Step 14. Clean Clean and check check the the rear sight sight assem assembly bly for for azimuth azimuth and and elevation and lightly lubricate the sections designated by an "O”. Be sure sure to oil the the knob deten detent t (see view view B in figur figure e 28). If rear rear sight does not function properly, notify unit maintenance. (3) Proc Proced edur ural al Machinegun.

Step Steps s

for for

Clea Cleani ning ng

Spec Specif ific ic

Area Areas s

of

the the

M249 M249

29


FIGURE 28.

LUBRICATION OF BIPOD LESS AND REAR SIGHT ASSEMBLY.

(a) Regulator . Step 1. The regulato regulator r must be cleaned cleaned with with a special special tool called called a scraper. scraper. Clean the the gas vent vent hole of the regulato regulator r body as as indicated indicated in view A of figure 29 on the following page. Step Step 2. The regul regulato ator r body may may be heavily heavily foule fouled d and requir require e more thorough thorough cleaning. cleaning. Clean the the central central hole hole of the regulator regulator with the appropriate part of the scraper by turning it clockwise and pushing it inward to the bottom of the housing (see view B in figure 29). 30


Step Step 3. Use Use the protr protrud udin ing g tips of the the scrape scraper r to clean clean the two groo groove ves s of the regu regula lato tor r body body (see (see view view C in figu figure re 29). 29). The The regulator sleeve is generally not heavily fouled and can be easily cleaned with a rag.

FIGURE 29.

CLEANING THE GAS REGULATOR.

(b) Gas Cylinder and Piston. Step 1. Clean the front front of the the gas cylinder cylinder (internal (internal diameter) diameter) by inserting and turning the flat side of the scraper in the hole (see view A in figure 30 on the following page). Step Step 2. Clea Clean n the inter interna nal l groove grooves s of the front front side side of the gas gas cylinder using the flat side of the scraper (see view B in figure 30). 31


FIGURE 30.

CLEANING OF GAS CYLINDER AND PISTON.

Step 3. The grooves grooves of the piston piston should should be cleaned cleaned as shown shown in view view C of figure 30. Step Step 4. Clea Clean n the hole hole on the the front front of the the piston piston with with the the same same scraper part as the front hole of the gas cylinder (see view D in figure 30). 4.

Uni Unit Maintenance Pro Procedures

a.

Maintenance of Rod Buffer and Spring Assembly .

(1) Initial Setup. 32


(a) Materials/Parts. Clea Cleane ner r small arms repairman tool kit. (b) Personnel Required . (c) Equipm Equipment ent removed. (2) Proc Proced edur ural al (figure 31).

FIGURE 31.

for for

pres preser ervat vativ ive e

(CL (CLP) P); ;

Supply clerk/unit armor.

Condit Condition ion.

Step Steps s

lub lubri rica cant nt

Rod

buf buffer

Disa Disass ssem embl bly, y,

and and

spr spring

Insp Inspec ecti tion on, ,

asse assem mbly

and and

Repa Repair ir

DISSASSEMBLY, INSPECTION, AND REPAIR OF THE ROD BUFFER AND SPRING ASSEMBLY.

33


Step 1. Replace driving spring (1) if more than one broken strand is found or overall spring length is less than 18 and 9/16 inches long. Step Step 2. Place Place the rod rod buffer buffer assemb assembly ly (2) in vise vise with with protect protective ive jaws in a vertical position. Step Step 3. (4).

Use punch punch and and hammer hammer to drive drive out pin pin (3), and and remove remove rod

Step Step 4. Unscre Unscrew w and separa separate te spring spring pin pin (5), ring ring spacer spacer (6), (6), and buffer spring (7). Step Step 5. 5. Visual Visually ly inspec inspect t rod rod (4). (4). missing, replace.

If bent, bent, or tip of rod (4) is

Step 6.

Check spring (7) for cracks.

If spring is cracked, replace.

Step 7.

Check spacer (6) for burrs.

Remove any burrs that are found.

Step 8. Check spring pin (5) for missing threads or cracks. spring if damaged.

Replace

(3) Procedural Steps for Reassembly (figure 32).

FIGURE 32.

REASSEMBLY OF THE ROD BUFFER AND SPRING ASSEMBLY.

Step 1. Install buffer spring (1) over spring pin (2). spacer (3) with beveled side out and insert rod (4). 34

Install ring


Step Step 2. Screw Screw spring spring pin (2) (2) until until it is flush flush with with or just just below below the pin hole in spacer (3). Step 3.

Align the slot in spring pin (2) with holes in spacer (3).

Step Step 4. Use Use a hamme hammer r to driv drive e pin (5) unti until l equal equal leng length ths s are exposed on each side of the ring spacer. b.

Maintenance of Trigger Mechanism Assembly .

(1) Initial Setup. Tools and Specia Special l Tools Tools. (a) Tools box spanner.

(b) Materials/Parts.

Small Small arms arms repair repairman man tool tool kit; kit;

Cleaner lubricant preservative (CLP).

(c) Personnel Required . (d) Equipment Condition.

Supply clerk/unit armorer. Trigger mechanism removed.

Procedural ural Steps Steps for Disass Disassemb embly, ly, Cleani Cleaning, ng, Inspec Inspection tion, , and (2) Proced Repair.

Step Step 1. Open Open plate plate asse assemb mbly ly (1). (1). Usin Using g 11m 11mm m end end of box box spa spann nner er tool, and screwdriver or punch, loosen machine bolt (figure 33 on the following page). Step 2. 33).

Remove machine bolt (2) (2) and pistol pistol grip grip housing housing (3) (figure (figure

Step 3. 33).

Remove trigger guard (4), (4), and and front spring pin (5) (figure (figure

Step 4. Inspect spring pin (1) without removing housing. spring pin is defective (see figure 34 on page 37). Step Step 5. Inspec Inspect t trigge trigger r guard guard (2). (2). (see figure 34).

Replace if

Replace Replace if sprung sprung or cracke cracked d

Step Step 6. Insp Inspec ect t pis pisto tol l grip grip (3) (3) for for crac cracks ks or break breaks. s. pistol grip if defective (see figure 34).

Repl Replac ace e

35


FIGURE 33.

DISASSEMBLY OF TRIGGER MECHANISM.

Step 7. Check plate (4) (4) and closure locking locking clip (5) for cracks or bends. bends. Replac Replace e plate plate assembl assembly y (6) if eithe either r part is is defecti defective ve by removing retaining pin (7) (figure 34 on the following page). Step 8.

Clean all parts with a rag dampened with CLP.

(3) Procedural Steps for Reassembly . Step 1. 1. Place trigger trigger housing housing (1) (1) with with trigger trigger facing facing upwards upwards (see figure 35 on the following page).

36


FIGURE 34.

FIGURE 35.

INSPECTION OF THE TRIGGER MECHANISM ASSEMBLY.

REASSEMBLY OF TRIGGER HOUSING AND TRIGGER GUARD.

37


Step 2. Hook trigger trigger guard (2) behind behind spring spring pin pin (3) (figure 35 on the previous page). Step Step 3. Insert Insert machi machine ne bolt bolt (1) into into pistol pistol grip grip housing housing (2) (2) and place on trigger housing (3) securing rear portion of trigger guard (4) (figure 36). Step 4. Using I1mm end of box spanner tool and screwdriver or punch, tighten machine bolt (1) (figure 36).

FIGURE 36.

38

REASSEMBLY OF PISTOL GRIP HOUSING.


Step Step 5. Instal Install l retaini retaining ng pin (5) (5) securing securing plate plate (6) (6) and locki locking ng clip (7) in pistol grip housing (2) (figure 36 on the previous page). Step 6. c.

Close plate assembly (8) (figure 36).

Maintenance of Receiver Assembly .

(1) Initial Setup. (a) Tools and Special Tools. (b) Personnel Required . (c) Equipment Condition.

Small arms repairman tool kit.

Supply clerk/unit armor. Field stripped.

(2) Procedural Steps for Disassembly, Inspection, and Repair . Step 1. Compress Compress retaining retaining clip clip (1) loose loose from receiver receiver (2) (2) and lift lift ejector (3) from receiver (2) (figure 37 on the following page). Step 2. Remove retaini retaining ng clip (1) (1) and cartridge cartridge ejector ejector pin pin (4) from from cartridge ejector (3) (figure 37). Step 3.

Visually inspect parts for cracks or damage.

Step 4.

Replace any unserviceable parts.

Step 5. Remove retaining retaining clip clip (1) from from headed headed grooved grooved pins pins (2) and (3) on the rear portion of receiver (4) (figure 38 on the following page). Step Step 6. 38). Step 7.

Remove Remove groov grooved ed pin assem assembly bly (2) (2) from recei receiver ver (4) (4) (figure (figure

Remove grooved pin (3) and retaining clip (5) (figure 38).

Step Step 8. Visual Visually ly inspec inspect t parts parts for cracks cracks or burrs. burrs. unserviceable parts.

Replac Replace e all

39


FIGURE 37.

DISASSEMBLY OF CARTRIDGE EJECTOR.

FIGURE 38.

DISASSEMBLY OF RECEIVER.

(3) Procedural Steps for Reassembly . Step Step 1. Insta Install ll retai retaini ning ng clip clip (5) and groo groove ved d pin (3) on lowe lower r portion of receiver (4) (figure 38). 40


Step Step 2. Install Install reta retaini ining ng clip clip (1) betwee between n outersi outerside de of flange flange on lower left hand receiver (4) and retaining clip (5) into groove on headed pin (3) (figure 38 on the previous page). Step Step 3. Inst Instal all l groove grooved d pin assem assembl bly y (2) into into receiv receiver er (4) and and insert retaining clip (1) (figure 38). Step 4. Install Install ejector ejector (3) on pin (4) and and snap retaining retaining clip clip (1) over groove of ejector pin with curved end overlapping front part of ejec ejecto tor. r. Inst Instal all l ejec ejecto tor r pin, pin, ejec ejecto tor r and and reta retain inin ing g clip clip onto onto receiver (refer back to figure 37 on the previous page). Step 5. Compress retaining clip (1) and install ejector assembly (3) into recess of receiver (2) (figure 37). Check for spring tension. 5.

Inter Interme medi diat ate e Dir Direct ect Supp Suppor ort t (ID (IDS) S) Maint Mainten enan ance ce Proc Procedu edure res s

a.

Maintenance of Barrel Assembly .

(1) Initial Setup. (a) Tools and Special Tools. Front sight base adjusting adjusting tool; small arms repairman tool kit; spanner wrench front sight post. (b) Materials/Parts.

As required.


Small arms repairer. Barrel removed.

(2) Procedural Steps for Disassembly of Front Sight Assembly (see figure 39 on the following page). Step Step 1. Drive Drive out pin pin spring spring (1) from from right right to left left with 5/16 5/16 inch inch punch and hammer. Step 2.

Remove front sight (2) and key (3).

41


FIGURE 39.

DISASSEMBLY OF FRONT SIGHT ASSEMBLY.

NOTE

If repl replac acem emen ent t part parts s are are requ requir ired ed (i.e (i.e., ., new new barrel (4) or, new sight (2)), the spring pin (1) must be replace replaced. d. The key (3) maintains maintains a rigid position of the front sight on the gas block (5) of the barrel (4). (3) Procedural Steps for Reassembly of Front Sight Assembly . Step Step 1. Place Place barrel barrel (1) in a prote protecti ctive ve jawed jawed vise, vise, clamp clamp in gas bloc block k area area with with the the front front sight sight portion portion up (see (see figu figure re 40 on the the following page). Step Step 2. Cent Center er sigh sight t asse assemb mbly ly (2) (2) on the the gas block block (3) (3) so one one serration serration is visible visible on each each side of of sight assembl assembly y (2). Install key (4) with the large chamfered (beveled) edge of the key to the left side of the sight. Step Step 3. Place Place the the tool, tool, front front sight sight adjust adjustin ing g (5), on the the front front sight (see figure 41 on the following page). 42


FIGURE 40.

FIGURE 41.

REASSEMBLY OF FRONT SIGHT ASSEMBLY.

REASSEMBLY OF FRONT SIGHT ASSEMBLY (CONTINUED).

Step Step 4. Push Push alignm alignment ent pin pin (6) in throu through gh the sigh sight t base and and key until it is flush with the inner curvature of the slot in the tool. Tighten two screws (7) snugly to hold tool (5) in place. Step Step 5. When When the desire desired d adjustm adjustment ent is obtai obtained ned, , place place spring spring pin (8) into the slot of tool (5) and 43


press spring pin (8) into place by turning screw (9) with screwdriver (see figure 42). Step Step 6. Loosen Loosen the the screws, screws, remov remove e the front front sight sight adjust adjusting ing tool, tool, and then restake the spring pin.

FIGURE 42.

b.

REASSEMBLY OF FRONT SIGHT ASSEMBLY (CONTINUED).

Maintenance of Cover and Feed Mechanism Assembly.

(1) Initial Setup. (a) Tools Tools and Specia Special l Tools Tools. small arms shop set. (b) Materials/Parts.

Small Small arms arms repair repairman man tool tool kit; kit;

Inspection penetrant; CLP.


Small arms repairer. Weapon field stripped (cover removed).

(2) Procedural Steps for Disassembly . Step 1. Remove retaining retaining clip (1), shoulder shoulder pin pin (2), and spring spring (3) (figure 43 on the following page). Step Step 2. 2. Insert Insert screwd screwdriv river er into into loop loop of retain retaining ing clip (4). toward feed mechanism assembly and remove (figure 43). 44

Pull Pull


FIGURE 43.

REMOVAL OF RETAINING CLIPS, SHOULDER PIN, AND SPRING.

Step 3. Lift feed lever (1) up and out from rear. spring (2) (figure 44 on the following page).

Remove retaining retaining

Step Step 4. Appl Apply y slight slight press pressur ure e to cart cartri ridge dge reta retain inin ing g pawls pawls and remove hooked retaining pin (3) (figure 44). Step 5. Remove front (1) (1) and rear rear (2) cartrid cartridge ge retaining retaining pawls pawls and remove two cartridge pawl helical springs (3), link ejection cover (4), (4), cart cartri ridg dge e indi indica cato tor r (5), (5), and and cart cartri ridg dge e indi indica cato tor r heli helica cal l compression spring (6) (figure 45 on the following page). Step Step 6. 6. Using Using small small screwdr screwdrive iver, r, remove remove retain retaining ing ring (7). (7). feed pawl assembly (8) off feed pawl pivot post (figure 45).

Lift Lift

45


FIGURE 44.

FIGURE 45.

46

REMOVAL OF RETAINING SPRING AND HOOKED RETAINING PIN.

DISASSEMBLY OF FEED MECHANISM ASSEMBLY.


Step Step 7. Compres Compress s cover cover latches latches (1) (1) and using using screwd screwdriv river, er, pry pry out retaining clip (2). Remove two cover latches (1) (figure 46). Step Step 8. Remo Remove ve two selfself-lo lock ckin ing g screws screws (1) and lockw lockwas ashe hers rs (2) (figure 47).

FIGURE 46.

FIGURE 47.

REMOVAL OF COVER LATCHES.

REMOVAL OF REAR SIGHT ASSEMBLY AND COCKING COVER CHANNEL.

47


Step Step 9. page).

Remove Remove rear rear sight sight assemb assembly ly (3) (figu (figure re 47 on the previ previous ous

Step Step 10. 47).

Pry retai retainin ning g spring spring (4) over over retai retainin ning g pins (6) (6) (figure (figure

Step 11. 11. Remove pins pins (5), (5), spring spring (4), and and cocking cocking cover cover channel channel (6) from from cove cover r asse assemb mbly ly and and sepa separa rate te spri spring ng (4) (4) from from cock cockin ing g cove cover r channel (6) (figure 47). (3) Procedural Steps for Inspection and Repair (see figure 48 on the following page). Step Step 1. broken.

Repl Replac ace e retai retaini ning ng clip clip (1) if it is weak, weak, defo deform rmed ed, , or

Step Step 2. Replac Replace e retaini retaining ng spring springs s (2) and (3) (3) and retai retainin ning g clip (4), if they have lost spring tension. Step 3.

Replace cover latches (5) if they are cracked or deformed.

Step Step 4. Replace Replace heli helical cal cartr cartridg idge e pawl sprin springs gs (6) if spri springs ngs are are crac cracke ked, d, brok broken en, , or have have lost lost thei their r spri spring ng tens tensio ion. n. Repl Replac ace e retaining ring (7) if broken or cracked. Step 5. Replace feed lever lever (8) if channel channel is distorte distorted, d, or cracked, cracked, or if pivot hole (9) is elongated or enlarged. Remove any burrs. Step 6.

Replace hooked retaining pin (10) if bent or broken.

Step Step 7. Cart Cartri ridg dge e cracks.

Repl Replac ace e rear rear cartr cartrid idge ge retai retaini ning ng pawl pawl (11) (11) and front front reta retain inin ing g pawl pawl (12) (12) if they they are are bent bent, , brok broken en, , or have have

Step Step 8. Replac Replace e cover cover (13) (13) if cover cover has crack cracks s or if pivot pivot posts posts (14) are broken, loose, or bent. Step Step 9. broken. Step 10.

48

Repla Replace ce feed feed pawl pawl assemb assembly ly (15) (15) if pawls pawls are crack cracked ed or

Replace rear sight if sight base (16) is cracked or broken.


FIGURE 48.

INSPECTION AND REPAIR OF COVER AND FEED MECHANISM ASSEMBLY.

(4) Procedural Steps for Reassembly . Step Step 1. Instal Install l two retain retaining ing pins pins (1) from from insid inside e of cover cover (see figure 49 on the following page). Step Step 2. Attach Attach sprin spring g (2) to cockin cocking g cover cover channel channel (3) (3) and secure secure cover to retaining pins (1) with spring (2) (figure 49). 49


FIGURE 49.

REASSEMBLY OF COCKING COVER CHANNEL AND REAR SIGHT ASSEMBLY.

Step 3. Align holes of rear sight (4) with holes on top of cover (5) (figure 49). Step 4. From inside inside cover, cover, install install two two lockwashers lockwashers (6) (6) and two two self locking screws (7). Tighten the two screws securely (figure 49). 50


Step 5.

Install two cover latches (1) (figure 50).

Step Step 6. Comp Compre ress ss cover cover latch latches es and insta install ll retai retaini ning ng clip clip (figure 50).

FIGURE 50.

(2) (2)

INSTALLATION OF COVER LATCHES AND RETAINING CLIP.

Step 7. Place feed feed pawl pawl assembly assembly (1) on feed pawl pivot pivot post post (2) and and secure with retaining ring (3) (figure 51 on the following page). Step Step 8. Plac Place e cartri cartridg dge e pawl helic helical al sprin springs gs (4) and cart cartri ridg dge e indicator helical spring (5) in recessed holes in cover (6) (figure 51). Step Step 9. Inse Insert rt cart cartrid ridge ge indic indicat ator or (7) in cove cover r (6) resti resting ng on helical spring (5) (figure 51). Step 10. 10. Start hooked retaining retaining pin (8) through through cartrid cartridge ge indicator indicator (7) and into cover housing holes (9) (figure 51). 51


FIGURE 51.

REASSEMBLY OF FEED MECHANISM ASSEMBLY.

Step 11. Place together front (10) and rear (11) cartridge retaining pawls (figure 51). Step 12. Place front front (1) and and rear (2) (2) cartridge cartridge retaining retaining pawls pawls onto onto cover (3) (see view A in figure 52 on the following page). Step 13. Place front front (1) and and rear (2) (2) cartridge cartridge retaining retaining pawls pawls onto onto cartridge pawl helical springs (4) (see view B in figure 52).

52


FIGURE 52.

REASSEMBLY OF CARTRIDGE RETAINING PAWLS AND LINK EJECTION COVER.

Step 14. 14. Compress Compress front front (1) and rear rear (2) (2) cartridge cartridge retaining retaining pawls pawls and helical springs (not shown) to align holes of front (1) and rear (2) cartridge retaining pawls with holes in cover (3) (see view C in figure 52). Step 15. Align link ejection cover (5) holes with front (1) and rear (2) cartridge cartridge retaining pawl holes and holes in cover (3) and push in hooked retaining pin (6) through all aligned holes (see view C in figure 52). Step 16. 16. Lift straight straight leg leg over hooked leg of retainin retaining g spring spring (1). Install loop of retaining spring (1) over the feed lever pivot (2) with legs of retaining spring (1) pointing forward (figure 53 on the following page). 53


FIGURE 53.

REASSEMBLY OF FEED LEVER.

Step Step 17. 17. Engage Engage the feed feed lever lever (3) on roller roller (4). (4). Place Place on pivot pivot (2) and and drop in place place. . Be sure sure feed lever lever (3) (3) is flush flush with top top of feed lever pivot (2) (figure 53). Step 18. 18. Install retaining retaining clip clip (1) (1) with legs pointed pointed rearward rearward and loop of clip toward feed cover (2) and push into position on feed lever pivot (3) (figure 54 on the following page). NOTE

Retaining secured.

clip

(1)

will

lock

when

properl erly

Step Step 19. Unho Unhook ok strai straight ght leg leg of retai retaini ning ng sprin spring g (4) by hold holdin ing g hooked leg in place with screwdriver (figure 54).

54


FIGURE 54.

6.

REASSEMBLY OF FEED COVER.

Conclusion

This This comp comple lete tes s the the disc discus ussi sion on of the the main mainte tena nanc nce e and and insp inspec ecti tion on procedures procedures for the M249 machinegun. machinegun. The situations situations describ described ed in this this task task were were only only exam exampl ples es of proc procedu edure res s that that are are neede needed d to perfo perform rm main mainte tena nanc nce e of the M249 M249 mach machin ineg egun un. . Prio Prior r to worki working ng on any any equipment, ensure the required TMs are on hand and are being used. For the M249 machinegun this would include both TM 9-1005-201-10 and TM 9-1005-201-23&P.

55

M249 MG MAINTENANCE - OD1505 - LESSON 1/PE 1

PRACTICAL EXERCISE 1 1.

Instructions

Read Read the the scen scenar ario io and and resp respon ond d to the the requ requir ireme ement nts s that that foll follow ow the the scenario. 2.

Scenario

SSG Thatcher is an instructor in the Artillery Branch of the Weapons Department. Department. After 2 years years of instruct instructing ing in this this branch, branch, he has been been informed that as of Monday he will be teaching the M249 machinegun, whic which h is in the Small Small Arms Arms Branch Branch of the same same depar departme tment nt. . Bein Being g unfamiliar unfamiliar with small arms after so many years of teaching teaching artillery, he decides to give himself a sample test to see how much he really knows about the M249 machinegun. 3.

Requirement

Belo Below w is a list list of ques questi tion ons s he feel feels s will will give give him him a gene genera ral l knowledge of the operation and maintenance of the M249 machinegun. a.

What What is is the the purp purpose ose of the the but butt t stoc stock k and and shou should lder er assem assembl bly? y?

b. What What is is the the rate rate of of fire fire of of the the M249 M249 mac machi hine negu gun n when when it it is set set on MAX? c. What What is the the firs first t step step tha that t shou should ld be be perf perfor orme med d when when loadi loading ng the the machinegun? d.

What What con condi diti tion on exist exists s whe when n a live live round round is stuc stuck k in in the the wea weapo pon? n?

e.

How How wou would ld a run runaw away ay mach machin ineg egun un be desc descri ribe bed? d?

f.

What What thr three ee comp compon onent ents s mak make e up up the the opera operati ting ng rod rod ass assemb embly ly? ?

g. What What par part t of the the mach machin ineg egun un mus must t be remo remove ved d befo before re rem remov ovin ing g the the bipod? h. What What is is used used to to clea clean n the the bore bore of of the the barr barrel el whe when n heav heavy y depo deposi sits ts are present?

56


i. When checking the driving spring for broken strands, unit maintenance maintenance would be notified if how many strands on the same coil of the spring were broken? j. Wha What tool is use used to tighten the mach achine bol bolt of the trig rigger mechanism during reassembly? k. When inspecting the cover and feed mechanism assembly, the retaining clip would be replaced if it was _________________________.

57


LESSON 1. 1.

PRACTICAL EXERCISE - ANSWERS

Requirement

a. The butt stock and shoulder assembly serves as a shoulder support support for for aiming aiming and and firing firing the mach machine inegun gun. . It also also contain contains s a folding shoulder rest. b.

The The max max rate rate of fire fire is 1000 1000 rds/ rds/mi min. n.

c.

The The fir first st step step is to char charge ge the the wea weapo pon. n.

d. A live live rou round nd is is stuc stuck k when when the the rou round nd did did not not fir fire e and and did did not not extract. e. A runa runawa way y mach machin ineg egun un can can be desc descri ribe bed d as a mac machin hineg egun un that that won won't 't stop firing. f. The thre three e comp compon onen ents ts that that mak make e up up the the ope opera rati ting ng rod rod asse assemb mbly ly are are a spring, a guide rod, and a buffer. g.

The The ga gas cy cylinder mu must be be re removed.

h.

The The bor bore e of of the the barr barrel el is clea cleane ned d wit with h a bore bore brus brush. h.

i. Unit Unit main mainte tena nanc nce e would would be noti notifi fied ed if more more than than one one stra strand nd was was broken. j. The The 11mm 11mm end end of of a box box span spanne ner r tool tool, , and and a scre screwd wdri rive ver r or pun punch ch, , are used to tighten the machine bolt. k.

58

weak, de deformed, or or br broken.

M249 MG MAINTENANCE - OD1505 - REFERENCES

REFERENCES

59

M249 MG MAINTENANCE - OD1505 - REFERENCES

REFERENCES The following documents were used as resource materials in developing developing this subcourse: TM 9-1005-201-10 TM 9-1005-201-23&P

60

M249 MACHINEGUN

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