(1957) tm 9-2111-1 field maintenance cal. 30 browning automatic rifle m1918a2

8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2

1/41

DEP RTMENT

OF

THE RMY

lfTVl (ij)o0)111111o11

T E C H N I CA L MAN UAL

MJ

Q J L £U

FORMERLY Til

9-1211)

DEPARTMENT

OF

THE

A I R i f l n l 1 1 1 1 \ Y . V / 0 o ~ o 0 o 1 1 0 0

FORCE

TECHNICAL

ORDER J U U U \ ~ QJJ

UL £{£

FIEL M INTEN NCE

CAL 3 BROWNING


2/41

This manual is correct to J anuary 957

TM

9- 2111 1 TO 11W3 5 3 122

TECEINLCAL

1\ IA

UA L l

No . 9- 2111- 1

T ECIINI CAL OR ER

No 11W3- 5- 3- 122

DEPARTl\IENTS

OF THE ARl\IY AND

THE

AIR

FOR E

W ASH

L \ GTOX

25, D. C.,

/8

Febmary 957

CAL. .30 BROWNING AUTOMATIC

RIFLE

Ml918A2

Parng-raJ Pn f"'

C' II AI TER

I.

l N TRODUC'T 0:\1 __ _ _______ _ ______ ___ __ _

__

__ _ 2

ion

C HAPTER

crtion

CHAPTER

, et tion

l.

ll

2.

3.

I.

II.

III.

IV.

4.

I.

II

.

ll l .

IV.

v.

VI.

VII .

VIII.

IX.

X.

XI.

c:eneral_______________________________________ _

D e. r ription and data_____________________________

PARTS

, SPE 'lAL TOOLS.

EQlf

iPl\IENT

FOR

FIELD MAlNTENAXCE_ ______________ _

I

N.

PECTIONS _____ ___________________________ _

GeneraL

__________________ __________________

__

_

In

spection of mat eriel

in

h

ands

of t roops___________ _

Pr

ee

mbarkation

inspection ________________________

I nsp

ect

ion of materiel received in

ordnanc

e s hops ___ _

REPAIR____________________________________ __ _

GeneraL _______ _____

____

_______________________

Trigg

er guard asse mbly ___________________ _______ _

Barrel and reC eiver group_________________________

Bolt group _________ _____ ________________________

Butt stock, bufl'er, and

ac t

uato r group ____________ _

lid

ea

nd pi

sto

n

group

____ _______

____

_________

__

_

Gas cylinder and forea rm group_- - - -

Rear sight assemb ly ____ _____________ ---_

l\l agazine assembly __________ _____ ___________ ___ _

Bipod

assembly ________________________________ _

'a.l. .30

joint

ed cl

ea

ning rocll\1L _________________ _

C HAPTER

5. F INAL N ~ P

ri O

N _________________________ _

APPENDIX.

R

EFERE. CE -------- --

-----------------------

Ix

EX _ __ ______________________________________ _____

_________

_

1- 3

4,5

6- 9

10- 12

13-27

2 ,29

30,3 1

32

-

43

44

- 49

50- 53

54 5

59- 62

63-66

67

- 70

71-

75

76-79

Q-4

5, 6

87, 8

:2

3

7

1L

lL

J

:2

18

1\

21

21

25

32

< 4

·

16

52

56

63

66

68

6

71

72

75

*

This manual

s

upersedes

TM 9-1211, 15 September 1947,

and

those portions

of

TB

ORD

507, 1 April 1953, and TB ORD 587, 20 December 1954, pertaining to the

equipment describ ed in this manual.

AGO 4471B-:'-ltLr.


3/41

CH PTER 1

INTRODUCTION

Section I. GENERAL

1. Scope

a These instructions are published for the use of personnel responsible

for field main tenan ce of this materiel. They contain information on

maintenance which is beyond

the

scope of the tools, equipment, or

supplies normally available to using organizat ion . Thi s publication

doe. not co ntain information which i intended primarily for the using

organization since uch information is available to ordnance maintenance

per ·onnel in FM 23- 15.

b Thi s publication contains a description of and procedures for re

moval, di

a.

sembly , inspection, repair and assembly of the cal. .30

Browning automatic rille M1918A2. The appendix contains a list of

current references, including supply and technical manuals form

s,

and

other available publicat ions applicable to the cal. .30 Browning auto

matic rille 11918A2.

c. FM

23-15 contains operating and lubricating in

st

ru

ct

ions for t

he

mate riel and all maintenance operation allocated to using organizations

in performing maintenance work within their scope.

d. Thi s publi

ca t

ion differ from TM 9- 1211, a follow :

1) Adds information o

a)

In spections.

b)

Ca

l. .30 jointed cleaning rod n

2)

Revises information

on

-

a) Field maintenan ce allocation.

b)

Forms, records, and r ports.

c) Parts, spec ial tools, and equipment for field

maint

e

nan

ce.

d) Repair of the weapon.

2. Field Maintenance Allocation

Th

e publication of instructions fo r

co

mplete disas embly is

not

to

be

co nst rued as authority for the perfo rmance by eld maintenance units

of tho e fllllctions which have been rest ricted to depot shops and arsenals.

In

general, the

pr

e cribed

maint

enance responsibilities will apply as re

l

ected in the allo

cat

ion of maintenan

ce

parts listed in the appropriate

co

lumns of ORD 8 S JL A-4. In st ructions for depot

main

tenance

ar

e

to b u eel by maintenance companies in the field only when the tactical

ituat ion makes

the

repair function imp erative. Provision of parts

li sted in the depot guide co lumn of ORD 8 supply manual will be made

to eld maintenance only when the maintenance to be performed has

b

ee

n

ce

rtified

by

a respon ible officer of the requisitioning organization .

2

AGO

4471B

3. Forms Records and Reports

a

General.

Responsibili ty for

the

proper execution of forms, record

s,

and reports rests upon the officers of all units maintaining this equip

ment However , the value of accurate records

must

be fully appreciated

by all persons respon ible for compilat ion maintenance, and use. Rec

ords, reports, and authorized forms are normally utilized to indicate the

ty

pe,

quantit

y, and condition of m

ate

riel

to

be in pected, repaired, or

used in repair. Properly executed forms convey a uthorizati on

and

se

rv

e

as records for repair or replacement

of

materiel in the hands of troops and

for delivery of materiel req uiring further repair to ordnan ce shops. The

forms, record , and reports e tablish the work required

the

progress of

the work within

the

shops,

and the stat

us of

the

materiel upon complet ion

of

it

s repair.

b. Authorized Fo rms.

Th

e forms generally applicable to units main

taining these weapons are li ted io the appendix. For a complete listing

of all forms, see DA P

am

310- 2.

For

instructions on u of t hese forms,

refer to FM 9- 10 .

c Field Report of Accidents.

1) I nju1·y to ersonnel or damage to materiel. The reports necessary

to comply with the requirem

ents

of the Army afety program

are pre cribed in d

eta

il in SR 385- 10- 40. Th ese report are

required whenever accidents involving inj

w-y

to personnel or

dan1age to materiel occw-.

2)

Ammunition

·wh enever an accident or malfunction involving

the use of amm unition occurs, firing of the lot which malfwlc

tions will be imm ecliately discontinued.

In addit

ion to

any

applicable reports required in 1) abov , d

eta

ils

of

the accident

or malfllllction will be reported as prescribed in SR 700--45-6.

d. Report of nsatisf

ac

tory

q t ~ i p r n e n t

or

lv

aterials. Any deficiencies

detected in the eq uipment covered herein,

wh

ich occur under the cir

cum stances inclicated in AR 700- 38 should be immediate ly reported in

accordance with the applicab le instructions

in

cited reg ulat ion.

Section II. DESCRIPTION ND D T

4. Description

figs .

1

and 2)

a The cal. .30 Browning automatic rifle

r

1J918A2 is an air-cooled,

gas-operated, magazine-fed, shoulder-type weapon.

t

i primarily com

posed of a barrel and receiver group, trigger guard assembly, gas cylinder

and forea

rm

group, slide

and

piston group, rear sight assembly, bu

ff

er

group, hinged butt plate assembly, magazine a sembly, bipod assembly,

and bolt group.

b Th

e trigger guard a .·emb ly,

lo

cated on the bottom of the receiver,

acts as a housing for the trigger mechanism, ejector, magazine catch,

and cyclic change lever.

AGO 4471B

3


4/41

4

0

a

AGO

H71B

'

'

.

...

0

a

AGO

4471B

:;;

...

'

53

..:::.

- '

;..

;,

2

-.

:::

-

-:

':::.

. -

....

g

<

' '

::;

,

s

0

i

t

5


5/41

c

On the front of the recei

ver

, just below

the

barrel, is the gas cylinder

and forearm group, within which the slide and pi ston group reciprocates,

actuated by gas pressure and the reco il spring.

d

The rear s

ight

assembly is located on the top of

the

receiver

ju

st

forward of the butt stock.

e.

In

side the butt stock is the buffer tube , which hou ses

th

e buffer

group, co mposed of alternate co nes and cups, and the actuator which,

co mbined with the actuator spring, operates

in

the passage formed by

the actuator tube.

f Th

e rear end of the stock is closed by the hinged butt plate assembly.

g

Th

e magazine assembly, located on

the bottom

of

the

rece

iv

er to

wards the front, holds 20 round

s.

h The

bipod assembly is

mounted with

the

fl

ash hider

and

bipod

bearing on the front of the barrel.

i . The bolt group, housing

the

firing pin and ext ractor, operates inside

the

receiver .

j. Th e rifle is furnished with a cyclic rate m

ec

hanism housed

in

the butt

stock with a trigger guard mechanism. The cycli c ra te mechanism al

lows two rates of automatic fire, 550 rounds per minute normal cyclic

rate) and 350 rounds per minute slow cyclic rate) .

5. Tabulated Data

Weight complete with bipod and magazine

assemb

li

es)_

_____

_______________

_____

l 9.

4lb

Weight

l

ess bipod) _

__ _______

_

_____

_

____ 17lb

Weight of bipod assembly___

___

___________ 2.38 lb

Weight of magazine assembly__________ __

0.44lb

Weight of moving part s ___________ _____ _ 2.25lb

Weight of barrel_ _________ _____ ____ ___ _ 3.65 lb

Length

of

rifl

e

____ __ ___

_

____

_____

_____

_ 4

7.

8 in.

L

engt

h of barrel_

___ __

__ _________ _

____

_ 24.07 in.

Length of rifling___ _

__

__ _______________ 71.1 ca

l.

21.41 in .)

Rifling:

umber

of grooves___

____

_

____

_

____

4

Ri

ght-handed twist

o

ne turn

in

) _____ 33.3 cal. 10 in

.)

De

pth

of grooves__ __ ______________ 0.0040 in.

Cross-sectional a rea of bore______________ 0.0740 sq in.

Type of

me

chanism_ __ ______ _____ ______ gas-operated

Feeding device ___ ____

__

_

____

___________ magazine

Capacity of feeding device______________ 20 rds

{

500 to 650 rds per min fast automat i

c)

Rate of fu·e _____ _______ _

_____

___

___ ___

_ 300 to 450 rds per· min s low a utomat ic)

Cooling system ___

__

_____ __ _________ __ _ air

Si

ght

radius________ ___ _

____

___

__

__

___

_ 31.125 in.

Trigger pull_____________ ____

____

_

_____

10 lb max; 6 lb min

Ammunition types ____ __ ____ _____ ___

___

ball; AP; tracer

AGO 4471B

CHAPTER 2

PARTS

SPECIAL

TOOLS

AND EQUIPMENT FOR

FIELD

MA

INTENANCE

6. General

Tools and equipment and maintenance part over and above those

available

to the

using organization are

sup

plied to ordnance

fi

eld main

tenance unit

s for maintaining and repairing the materie

l.

7

Parts

Main

tena

nce parts are listed in ORD 8 S L A-4, which i s the authority

for requisit ioning replacements.

8. Common Tools and Equipment

Standard and commonly used tools and

equipment having

general ap

plicat ion to this ma teriel are listed in ORD 6 SNL s J- 8 Section 6 and

J- 10 , Section 2, and are authorized by TA and TOE.

9 Special Tools and Equipment

Th

e special tools

and equipment tabulated in

table I are

li

:sted in ORD

6

St-.TL

J- 12.

Thi

s

tabulation

co

ntain

s only those special tools

and

equipment necessary to perform the operations describ ed in

this

publica

tion, is

in

cluded for inform

at

ion only, and is

not

to be used as a basis for

req

ui

sitions.

Note.

Special tool sets in ORO 6 SNL J- 12 , in audition lo ~ p i tools, a l o

con

ta

in

st and

ard and co mmonl y used tools and equipment spec ifica

ll

y

app

licable

to

this materiel.

Table I . p

ec

ial Tools and Eqtt ipmenl for Field Maintenauce

R eferences

Id entify ing

It

em

No.

Usc

Fig.

P ar.

BLOCK,

vise,

bbl

6316006

4,

10 50a 2)

To provide

positive

re-

holding, S.

tention

aud

prevent

distor t ion

of

ba

rr

el

wh en clamp ed in vise.

BR

US

H,

clean ing,

6528362

4

--

- - -

To clean the chamber.

chamber,

cal. .30,

Ml

EXTRACTOR,

rup - 5507912

4

-- - - - - -

--

-

--

For

extr act iu g

ruptur

ed

tw·ed cartridge case,

cartr

id ges.

ca l. .30, Mk II .

FILLER,

magaz

in

e,

5507913

4

------------

T o a iel in

loadjx1g maga-

ca

l.

.3

0.

zin e rapidly.

AGO

4471B

7


6/41

'l'able I. Special 'l'ool and Eq1tipment for Field Maintenance- continued

Hom

Hcfcrt ·es

I

Id cntifyiUJ< ,_ _ _ _ _

No. / Fil(.

Par. I

Use

- 1

GAGE, breech bore, 5 5 6 1 3 ~ : 3

cal. .30.

GAGE, headspace,

i3

199-14

cal.

.:30,

1.9.J.O in.

GAGE, headspacc,

7:3

19H5-I

cal. .30, 1. J50 in

GAGE, plug, NO GO,

"07720-1

gas

cyl, cal. .30,

dia 0.053.

GAGE, ring,

OGO, 5077201

piston dia, ca l. .30,

clia 0.- 94.

REFLECTOR,

bbl,

726578

cal

.. 30.

ROLL, tool, canvas G5U7:38 J

empty, i\Il2.

TOOL, alinement, 631G001

buffer tube, cal.

.30.

Composed of:

PARALLEL.____ 7ll3327

PLUG ____ _____ _ 7113326

SPACER________ 7113328

3

3, 5

:3 5

3, 2

3, 25

-l

- ,

] j

4, 16

.J , ] j

- ,

13,

2

TOOL, clean in g, gas 726

211 3, 27

l i n d

TO

OL, comb _______ _

72G6- 50 -

WRENCH

single,

G:316005 4, 10

8

open end, receiver

and

bbl.

J8t..,

5 l a(2J(cJ,

88

27b(1 ,

88

27b(2), 88

2:3.f,

68b(3),

8

20b, 64c(2J,

88

51a 2

l

(b

)

53a(:2)

53a 2

)

53a(2)

50r 5

),

53a(2)

23.f,

65a,

68b(2)

G7b(-l

), 69c,

70a

50a(2)

To

gage the lands at the

breech end of

the bar

rei

to detcrn

:tine its

serviceability.

To gage the distance be

tween the

~ h o u l e r

o

the

chn.m l or

and the

face of the bolt.

To gage the distance be

tween

the

shou ld er o

the chamber and the

face of the bolt.

To gage the in ide cliam

eter of the gas cyl

inder.

To

gage

the diameter

of

the piston.

To

provide a ligh t re

flecting surface for vis

ual inspection of rifle

bore without removing

the barrel from re

ccivcr .

To position the buffc

tube

in receiver so tha

one of eight grooves ir

bead of buffer tube

li

e

centra

ll

y horizonta

\l" th top of receiver.

To remove

ca

rbon from

gas cylinder and face

of piston.

To

assemble

and

disas

semble weapon (F:\

23- 15).

To remove receiver from

barrel.

AGO

4471B

CAL. .30 PISTON

DIA NO

GO

RING

GAGE 5077201

CAL

.30

BREECH BORE

.

GAGE 5564343

CAL. .30

GAS

CYLINDER NO

GO

PLUG GAGE 5077204

GAS• CYLINDER

CLEANING TOOL

7268211

1.940 IN. CAL .30

HEADSPACE GAGE

7319944

1.950 IN.

CAL. .30

HEADSPACE GAGE

7319954

RA PD

917520

igure

3. SJJeciol

tool

s for

Ji

eld maintenance.

AGO 4471B


7/4110

a

a..

AGO

447lB

CHAPTER 3

INSPECTIONS

Section I GENERAL

10 Scope

Paragraph

s

10

through 31 provide specific in

struct

ions for

the

techni

cal inspection by ordnance maintenance personnel of materiel either in

the hands of troops or when received for re

pair

in ordnance shops. t

also briefly describes

the in

-pro ce s inspection of

mate

riel during repair

and the final inspection after rep air has been completed . Troubleshoot

ing information is incorporated wherever applicable as a normal phase

of

in

sp

ect

ion .

11 Purpose of Inspections

In

spect ions

are

made for the purposes of 1) determining the condition

of an

item as

to servi ceability 2) recognizing conditions that would

cause failur e, 3) assuring proper application of maintenan ce policies

at

prescribed levels, and 4) determining the ab ility of a unit to accomplish

its maintenance and supply mis. ·ions.

12 Categories of Inspection

n general, five categories of inspection are performed by ordnance

mai

ntenance

personne

l.

a O

verall

Inspection Thi s is a periodic overall inspection performed

by

a c

ont

act

party

on

ma t

eriel in

the han

ds of troops

and an

inspection

performed by maintenance company personnel when materiel is evacu

ated

to the ordnance company. The inspection of evacu

ated ma t

eriel

is

more

thorough and includes check and re

pair

of minor points

that

should not be required in the inspection performed by a contact party .

b reem bcakation Inspection This inspection is conducted on materiel

in alerted units scheduled for oversea

duty to

insure th

at

such materiel

will not become unserviceable or

~ o r

out

in

a relatively short t ime.

t

pre scribes a higher percentage of remaining usable life in servi ceable

mat

eriel to

meet

a specific need beyond minimum serviceability.

c I

n P1·ocess

I nspections These are inspections performed in the

process of repairing the

mat

eriel. Th is is to insm e that all parts con

form

to

the prescribed

sta

ndard

s,

that the workmanship is in accordance

with

app

roved method s

and

pro cedures,

and that

de

i

ciencies

not

dis

closed

:: the

preliminary inspection are found

an

d corrected. Detailed

inst ructio s are contained in chapter 4.

d. F

in

l I nspection Thi

s is

an

acceptance inspection performed by a

final inspect or after repair h

as

been complete d, to insure

that

the materiel

is acceptable for return to user according to the standards establi he

l

.

Detailed

inst

ru

ctions are contained

in

chapter

5.

AGO

4471B


8/41

e. Spot Check spe

ct

i on. This is a periodic overall in spection per

formed on only a percentage of t he materiel in each unit, to determine

the ad equacy and effect iveness of organizational and fi eld maintenance.

Section II INSPECTION OF MATERIEL

N

HANDS OF TROOPS

13

Precautions

Before start ing a t echnical inspection, be sure to clear t he weapon . Do

not

tou

ch

th

e trigger until

the

w

ea

pon has been cleared .

In

sp

ec

t

the

bore and hamber to insure that th ey are empty and check to see

that

no ammunition is in

po

sition to be in troduce d. Avoid having live

am-

munit ion in

th

e vicini

ty

of

th

e work.

14

General

a. R efer toT 9- 1100 for res ponsibilities and fundamental du ties of

in pecting personnel, the neces ary notice and

pr

epara tions t o be made,

forms to be used, and general procedm es and methods to be followe d by

in p

ect

ors. Materiel t o b e

in

spected includes organi zational spare part s

and equipment and

th

e s tocks of cleaning

and

preserving ma

te ri

als.

b. Check to see th at the weapon ha been cleaned of all corrosion

prevent i

ve

compound, grease, excessive

oil

,

dirt

, or foreign ma tt er whi ch

might in terfere with proper fun ctioni ng or obscure the true condi tion of

th

e parts .

c. fake an overall in pection of the weapon for general

app

earance,

condit ion, opera tion , and manual fun ctioning. U. e dummy or drill

car tridge .

d . D ete rmi ne servi ceabili ty, i . e., the degree of serviceability, com

pl ete ne , and reacliness for immediate use, wi th pec ial reference to safe

and proper functioning o f t he mate

ri

el. f the ma teriel is found service

abl e it ill be ontinued in servi ce.

In

the eve

nt

it is found un ervi e

a ble or incipient failm es are dis

cl

o eel , t he de

fi

ciencies will be corrected

on t he pot or advi ce given

a:

to corrective measm es when applicabl e,

or,

i

nece ary, the mate riel \\ill be tagged for delivery to and repair by ,

ordnance ma

in

tenance per onne

l.

e.

Determine cau ses of mec hanical and ftmctio

na

l difficulties that

troops may be expe

ri

encing

an

d chec k for a

pp

arent re ult s of lack of

lrno ,Yle

cl

ge mi information neglect , improper handling and storage, se

c

mi

ty , a nd prese

rv

ation.

f

Check

on

appli

cat

ion of all urgen t modifications,

and

if

any

un

a

uthOL

·ized a

lt

erations have been m ade, or if work beyond the a uthorized

scope of the unit is bein g attemp ted 'l:WO ORD A4- W6 which provides

the rifle wi th the late:t gas cylinder assembl y is co

ns

idered mand

at

or

y;

however, a] o check DA Pam 310- 4 an d the current modification \\"Ork

order

fi

le for any additional work orders promulgated ubse

qu

ent to

this pr inting.

12

AG

O

4


9/41

d In

speet locking

act

ion of bolt lock

and

bolt.

e

Fire

several rounds of service ammLmition, and examine primers of

fired casings. f primer shows indi cations of being set back in firing pin

ho

le of bolt, due to

an en

larged

fi

ring

pin

hole or re essive weat· of bolt

face, rep lace

the

bo l

t.

Warning:

Test -fire when

and

where conditions permit, consi

der

ing

safety and

expediency.

16 SIGHTS

a

Check

front

sight

ba

se for looseness on

the

barrel, and check blade

for looseness

in

the

base.

b

Blade

mu

st be st raight and top of the blade square and properly

darken

ed.

c In ·pect rear sight base for looseness on receiver.

d

In spect windage scale for looseness on base.

e

Check s

pring

for fun

ct

ioning.

f Inspect functioning of elevat ing >crew and leaf with slide. Both

mu

st operate freely and retain setting .

g

Windage

knob

will turn freely by hanrl and ret a

in

se t . An accept

able dull finish i s required on all

par

ts.

17 Bipod Group

a In spect bipod assembly for proper fit

on

flash hid er bearing.

b In spect bipod assembly for looseness on ba

rr

el.

c In

sp

ect

for missing or brok

en

friction washer and s

ight

cover.

d

Sliding legs will

move

read ily to any position and wil l be locked and

held by the bipod leg thumbscrews.

18 Barrel and Receiver Group

Note

Weapon must

be field-stripped FM 23- 15)

to

perform pertinent gage

checks.

a In spect

head

s

pa

ce as described in paragraph 27.

b Check breech bore dim ension, using breech bore gage 556 ±3 ±3

(

fig

. 3).

In

se

rt

the

gage

into the

chamber. Looking

through the

ejec

tion

port and

using

the

ca

librated

sca

le

of

the

gage, r

ea

d indi

cat

ion

that

appears

ju

st flush i\rith the r

ea

r face of the barrel. t should be 0.3

1

in ch or less.

c In sp

ect

receiver for wear, burs, rust,

and

foreign matter.

d

In s

pect

for loose bolt s

upport

s.

e Inspect bolt lock recess in top of receiver. Check especia lly where

lock seats when bolt is locked . Burs here will affect heads

pa

ce.

f In

spect operating handle for

funct

ioning

and

free moveme

nt in

slideways.

In

spect plunger for free movement and spring tension.

g

Top

plate should not be loose

and

a drive fit is required.

14

AGO 4471B

19 olt Group

a In

spe

ct

firing pin hole for out-of-round.

b

Check firing pin

protru

sion.

t

should be approximately

three

thirty-seconds inc

h.

c

Check firing pin for broken point, wear, bm s

and

fra

ct

ur

e.

d Remove ext ractor. Check spring for set or fracture and check lips

of

extractor

for wear.

e Check bolt link and lock for excessive wear, bur

s

and galling.

Check holes for out-of-row1d.

2

Slide and Piston Group

a

Check fit between piston

and

slide.

b

Total

endplay

of pi

ston

should approximate one-eighth inch in

any

direction

and fa

ce of piston

mu

st not st

rik

e

ga

s cylinder body when slide

is in

fully forward position. Gage piston, using NO GO gage

5077201

(fig. 3) . Piston head should not

enter

gage. To gage, first clean piston

thoroughly of

all

carbon and fouling, and d

ete

rmine that surfaces of

head

ring are smooth and polis

hed

. Wip e piston h

ea

d

and

gage

with

a slightly

oiled doth and try to pass gage over piston head . (Only light pressure

should be exert ed on gage.)

c In sp

ect

slide for

bur

s, def

orm

ation, galling, or battered r

ea

r end.

d Check hammer pin hole for out -of-round .

21 Trigger Guard Assembly

a Check functioning by

hand

operation.

b Check c

hang

e lever for

movement

in a ll po ition. aucl ability to re-

tain

sett

ing.

c heck ejector for bw·s fracture, or clefonnat,iou.

Check all springs for tension and set .

e Check magazine release

an

d catch for proper furtctioning.

Buffer and Actuator Group

a Check

actuator

for free movement

in actuator

tube.

b

Check

actuator

spring for kinks

ru

st,

and

free length.

c Check buffer head assembly for burs, missing key , and sear release

for free mov ement and correct assembly. Check cones and cups for set

and

proper assembly .

23 Gas Cylinder Group

a In

s

pect

gas cylinder for

dent

s, cracks, deformat ion ,

and

distortion.

b Check

ga

s port in the gas cylinder body to be sw·e it is free of car

bon

or

oth

er foreign

matter.

c Check gas cylinder body for

burred or

· stripped threads.

AGO 4471B

15


10/41

d

Check

the three ga port

s in the gas regulator for ca

rbon

or

other

foreign

matter.

e.

Be sure that dust ·bield is present.

f In spect, gas cylinder body for wear, using gas cylinder gage 507720±

(fig. 3). This is a N0 GO gag and boule

not

enter the gas cylinder

body. Before gaging the cylinder clean thoroughly

to

remove all car

bon

depo its

and

foreign matter, using ga cylinder clean ing tool 7268211

(fig. 4). Use crocus cloth to polish , and if nece

·sa

ry, wipe cylinder and

gage with a slightly oiled cloth and try to insert gage into cylinder. f

the

gage enters, it is unservi ceabl

e.

(Only light pre ure should be ex

erted

on gage.)

24

Stock

and

Forearm Group

a.

Butt

plat

e -ill fit properly and scre ·s will not be str

ipp

ed or have

mutilated beads.

b. Butt swivel ll'ill be secme, screws \\ill not be

mutilated, and

wivel

screw will be tight

and

taked.

c.

Butt

stocks will be checked for warping loose

fit , and

c

ra

ck .

d Forearm

will be in ·pected in accordance with inst ruct ions

in

para

graph

14j .

25

Trigger Pull

a.

Test trigger pull for

smoot

hness and

pre

sme exerted. Trigger pull

should be clean, without creep, and smooth in action. The for ·e exerted

to relea. e slide is no le

than

6

pound

, nor more

than 10

pow1ds.

f

the

pull i rough,

not

within pecified

limit

or excessive creep i pres ent,

check for vear or bw·s on ear

and

slide

notch

or for

in t

erference between

trigger and housing.

ole

The word " creep" is in terpreted to mean any pei·ce

pt

iblc movement

in

the

lrigger pull bet\\'een the time the slack is taken up and th e ide is relea ed, with

pressure app

li

ed

at

a uniform rate of increase over a period

of

not l

es

than 10 seconds.

b. In testing trigger pllll of rifles,

the

inspector will use two weight ,

one of 6 pounds

and

one of 10 pollnds.

c.

Check

to

insure

that

the

change lever is

set

at

the

A or F position

and

that

the

rifle is cocked.

Rest the

trigger "·eight on the floor or

ground, and inse

rt

the hook of trigger weight wire

th

rough

the

trigger

guard

body bow to bear on

the

trigger, so that pressme is applied one

quarter inch from the lower end or tip of trigger. With the barrel of the

rifle held at a 30° angle to

the

vertical, carefully rai e the weight from t he

floor.

f

the 6-

pound

weight pulls or the 10-pound weight fails to pull

the trigger to rel ease the slide, correct (par. ±6e). Exercise care during

the test to determine

that

the wire ontacts the trigger only bat

it

does not rub against the trigger guard body or stock, and tha wire and

axis of bore are parallel and perpendicular.

16

AGO 4471B

26

Equipment

a.

Make lu·e all spare

parts

and equ.i pment, are on

hand

and in good

eonclition.

b

Slings

will

be compl te a semblies with keepers, frog·, and hooks

attached. Leather

sling

wi ll

be .·oft

and

pliable. When the sl

ing

is

bent double over a l-inch rolU1cl bar, there should be no cracking of the

lea th

er

. L

ea t

her slings will

not

be issued when

the

pre ·ent supply is

dep l

eted

.

Web

lings wi not be

rotted

or baclly tainecl . Special

attention

should be given to

the

point at which

metal

is

attached,

to

see that ru

st ha

s

not

weakened the sling. lightly soiled web slings

may

be crubbe d with a mild ' '

o.

However, care should be

taken to

pre

se

rv

e the olive-dmb

co

lo'·

27.

Headspace

a.

Geneml

(1)

Definition

Headspace 1 cal. .30 Brmvning automatic rifle

l\l1918A2 is the clistance between the shoulder of the chamber

and

the face of

the

bolt when

the

bolt is

in

" locked position. "

(2) E.f) ect of heaclspace

on

operation f heaclspace is insufficient, the

bolt does not fu lly lock behind the cartridge IYithout being

forced.

f

headspace is exce. siv

e, the cart

ridge

ha

too much

play in

the

chamber wh en

the

bolt i · locked behind it. Either

conclition i

liD

afe .

3)

Cause of variation

n

heaclspace A· component parts of the rifie

are

manufactm d to close tolerances and headspaee is carefully

checked

at

manufacture, a variation usua

ll

y i due to wear ,

cau ing exces ·iv head pace

to

develop. However, assembly

of parts with maximum tolerances results in

eit

her excessive or

in suf

fi

cient headspace. Exces ive heaclspace due to wear is

caused by advanced c

hamb

er shoulder in

the

barrel, worn face

of bolt, 1vorn

lo

cking boulder of bolt lock or worn

lo

cking

reces in receiver.

b. Gaging H

eadspace

(fig. 5). Headspace is gaged with the firing pin

and extractor removed from the bolt, recoil spring and gllicle remov

c

from

the

slide

and

piston group, operating handle removed from the re

ceiver, and the trigger guard a· ·emb ly removed from the rifle. With

the

inspector's bore re flector, examine the c

hamb

er to mak certain that it is

clean.

Place

the bolt a sembly (minus firing pin and extracto r), with

bolt link assembled, in

the

receiver.

Then

install

the

slide

and

piston

group (minus spring and guide), and fit the

hammer

into its

seat

in . ide

and in. ert hamm r pin. Work the slide back and forth several times by

hand to

il1s

UJ

e that

the p a r t ~

are co rrectly as embled.

In

tall the ga.·

cylinder and forearm group and lock it in position with ga cylinder re

taining pin. \Yith slide pu heel fully

fonmrd

note the relative position

of the

hamm er

pin with reference to

the

fonmrcl part of

it

s ·lot inside

of.

AGO 4471B


11/41

receiver.

t

will be found that

there

is a clearance of from one

thirty-

second

to

three sixty-fourth s inch between the h

ammer pin an

d the for

ward part of

the

slot.

This po

sition of

the hammer

pin is referred

to

as

the "locked position. "

POSITION OF HAMMER PIN WITH HEAD

SPACE

GAGE-7319954

IN

CHAMBER

SHOULD NOT

BE

LESS THAN

3

/8

INCH FROM LOCKED POSITION

POSITION

OF

HAMMER PIN WHEN

IN

LOCKED

POSI

TION

WITH

HEADSPACE

GAGE-7319944

IN

CHAMBER SHOULD

BE

FR

OM

1

/32

TO

3/64

INCH

(1)

(2)

l

/32

IN. TO 3/64 IN

RA

PD 909308

Fig ure 5 Gaging heads pace

JYfinimum h

dspace

To

test for

minimLm1

headspace, place the

1.9-±0-inch headspace gage 73199H (fig. 3) in the chamber and

move

the

slide forward.

Note the

po ition of

the hamme

r pin .

t should be in the locked position (fig. 5) .

f

the hammer pin

is

in

the locked position, the minimum headspace is co

rr

ect.

f the hammer

pin

i ·

stopped before reachil:tg the locked posi

tion

, the

head

space is insufficient and should be corrected

by depot

maintenance.

Not e

Never use force again t th e gage to obtain locked position .

Ma ximwn

h

dspace

To test for

maximLLm

heaclspace, place

the

1.950-inch headspace gage 7319954

fig

. 3)

in the

ch

amber

and

move the slide forward until stopped by

the

gage. Note

position of hammer pin.

t

should be not less than three-eighths

inch from the locked position (fig. 5). f the hammer pin is not

stopp

ed

on or before

it

i ·

in tb.is position,

the head

space i. ex

cessive

and

should be corrected

by depot

maintenance.

Section

Ill.

PREEMBARKA TION INSPECTION

28 Rifle

a Proceed as in

paragraph

s

13 through

27

and in b and

c below.

b

Do

not

reject

the

rifle for oversea use unl ess exterior parts

have

a

distinct

shine; also, bright

rear

si

ghts

\ V i ii not

be

permitted on weapons

for overs

ea

u. e.

r The breech bore dimension (par. l8b) should be 0.306 inch or less.

AGO 4471B

29 Organizational Spare Parts Tools and Equipment

Examine

all s

par

e pa rts, tools,

and equipment

for completeness and

serviceabili

ty.

Rep lace any defective items.

t

is not normally neces

sa

ry

to in

s

pect

items

in

sealed packages,

si

uce

they have

been inspected

for serviceabi

li

ty prior to packaging

and

dW'iug ' torage.

Section IV. INSPECTION OF MATERIEL

RECEIVED

IN

ORDNANCE SHOPS

30 General

A

tec

hni

caJ

inspection imilar

to

that in

paragraphs lei:

through 27

i .;

performed.

In

add

ition, the

e:deut

of repa.irs necessary is determiuecl

and

an esti

mate is

made of the parts required. A

troub

leshooting iuspec

t ion i performed, as necessary, to localize malfunction and apply

co

r

rective me asmes.

31 Troubleshooting

Tab

le

II li. ts

mali'unction. , their probable causes

and

proposed cor

r

ec t

ive actions.

For

troubleshooting information " 'ithin the

sc

ope of

organizational maintenance, see FJ\I

23

- 15.

Malfunct

ion

Failure to feed _

____ _____

_

Failu re or slide to cock

Fai lme to tire ________ __ _

Table II Troubleshooting

Probable

c

aus

es

Dirty or dented magazine

body.

\Yeak or broken maga

zine spring.

\\

'orn or broken magaziuc

catc

h.

Damaged sear or sear

notc h in lid

e.

Broken sea r spring

__

____ _

Bu rs or foreign

matter

iu

sear notc h.

Failur

e of bolt lo r

etra ct

suffici entl y.

Weak recoil spring___ ___ _

\\ orn or broken iring

pin.

\Yorn

or

broken sea1

pring.

Defective sear or ha mme1

Weak ejection

__

________ _ \'Yarn ejector _ __________ _

1

AGO 4471B

Correeti

e

action

Rep lace magazine (pars. 76

anJ 79).

Replace magazine (pars.

76

and 79 ).

Hep lace magaz

in

e

ca

tch

(par ' . H and

- 7 ).

Replace slide or sea r (par

s.

- .J and - 7 ).

R epl ace sear -pring (pars.

-A and 47 .

Clean and remov.e u r ~

(pars.

44 a nd .J7

l

Cor r

ect

(pa

rs.

,J

-1

and

.J 7).

Heplace reco

il

spring

(p:1rs.

63

anti 66).

Replace fu·ing pin (pars. 5-l

nnd 57).

H.eplace s e ~ u · spring p : . t r ~ . -11

and 47 .

Replace sca r (pars. - -

mHI

-l7 ) or ha mmer (par . 54

w1d

57) .

Repai r ejecto r (par s .J -1 and

47 .

19


12/41

Table

II

T1·oubleshooting continued

Malfunction

Probable cau se

Failure to eject________ __ JJirLy or clogged ga ports_

Failure

to extract___ ____ _

Fai l

me

to pull off with

change lever set

at

For

A. Muzzle depre sed.

Broken ejector _____ ____ _

Weak or broken ejector

lo k and / or ejector

lock pring.

Damaged or

broken ex

tractor cl

aw

.

Broken or missing ex

tractor pring.

Sear pring not correctly

positioned.

Corrective

aclion

Clean and properly adjust

ga cylinder assemb ly

pars. 67 a nd 70).

Replace ejector pars.

4


13/41

(3) omplete disassembly of a w1it is

not

always necessary in order

to make a required repair or replacement. Good judgment

·bould be exercised to keep

el

i. assembly oper

at

ions to a min i

mum .

b

Replacement of Parts

I ) Un erviceable and unrepairable as. embl

ie

w

ill

be broken down

into items of issue and serviceable pa rts wi ll be returned to

stock.

Part

s or a semblie Lhat cannoL be r

epai

red or re

claimed to

the

.t a

ndard

s

et

forth in thi. pub lication will be re

p laced as indicated.

(2)

\\


14/41

f

weapons do not fun

ct

ion satisfactorily , additional rounds

are author

ized.

Weapon

s

that

fail

to

m

eet

the

test are

to be c

orr

ected

by

replace

ment of defective component or by performjng such repair

as

required.

b All weapons will be cleaned

as

soon

as

possible after all firing

tests

have been completed

and

each

day

thereafter for 3

day

s making a total

of

-

consecutive

day

s. An

alternate method

of scheduling cleaning op

erations

is

to

clean al l weapons i

mmediate

ly after fun

ct

ion-firing and two

successive times following

the

fu·st cleaning; cleaning in tervals should

be

at

l

east

16

hour

s 1\·ith

not more than

72

hour

s between

any

two suc

cessive cleanings.

c

Special care should be

taken to

insure that

bolt

faees, pi

st

ons ,

br

eech

end

of receiver,

and

other parts

s

ubjected

to

burned

powder resi

du

es are

tho

roughly cleaned.

The

se parts should be scru

bbed with

a

bri

st

le brush moistened with rifle-bore cleaner solvent cleanillg com

pound

.

d

A single cleaning of

the

bore

and

chamber of function-fu·ed weapons

with steam

or

hot water not

less

than

200°

F.

) is

acceptab

le in

Lieu

of

the

cleaning

in b

above .

The steam

or hot

water

may

be

applied by

hand

or

machine and the

bore

and chamber

air-dried.

The

bore

and

chamber

will

then

be

scrubbed with

a snug-fitting wire

bru

sh dipped in rifle-bore

cl

eaner

sol

vent

cleanillg

ompound.

Three m·y

patches

wi

ll then

be

pas sed

through

the bore and chamber, followed by one patch

saturated

with

prescribed oil.

43 Operations Route Sheet

The

information in

ta b

le

III

illu

st rate

s the sequence of operations neces

sa

ry

dming repair

of

the

weapon. Special machine

s, too

ls,

and

gages

required for

an

operation

are indicated

opposite

the

operation.

Table III

Op

erations Ra ttle Sheet for Cal O Browning Automatic Rifle ~ 1 1 9 B

Op

e

ration

No.

Operation Tools

\ ---

I • ac

hine

I

1

3

4

5

6

7

8

Unpack.

Degrease________________________ _ See Tl\1

9- 1005.

R ecord serial

numb

ers.

Di assembl e into ubasse

mb

lies______ ----- - -- - 7:266-±50

Disasseml le subassemblies

______

____

-- - ----

--

7:266-±50

Clean al l parts.

In

spect wooden components.

In spect m

eta

l compone

nt

s:

Inspect for excess ive ·ear in

bolt

lock shoulder in receiver.

In

sp

ect bo

lt assembly.

I

In spect gas cylinder_ _______ ___

In spect gas pi ton ___________ __ - - - - -- - - - - - - -- - - - - --

I

Gages

5077204

5077201

AGO 4471B

M19181Hi- continued

Operation

1 hi ne

Tools

Operation

I

No.

1

9

10

11

12

13

1-

15

16

In spe

ct

a

ll

other

parts

for se r

viceability.

R emove barrel from receiver if

necessary.

Inspect barrel and receiver:

In

spect barrel visuall . · for

pits

aucl dents.

In

spect bore_________________ _

Assemble barrel to receiver

or

re

barrel if neces ary.

Do

necessary repai ring or

part

.

n

required.

In spect .

Do necessary polishing of

pru t

R aR

required.

In sp

ect

.

Repa ir and sand stock and fore-

arms.

17

In

spect.

18 Sandblast parts

requiring refinishing.

19 R efinish.

20

Inspect

.

Vise

___

_

6316006,

6316005

7265788

Vi

se____ 6316006,

6316005

21

Assemb.le subassemb

li

es ________________

_____

7266-±50

22

Assemble subassemb

li

es to

ri.fi

e

______

7266450

23

In

spect.

24

Function- fire .

25

Do necessary repairing.

Note D o operations

23

anU

2 J

again if

repair is performed

26 Clean rifle.

27 Final inspection.

28

Record serial

uumh

er.

29 Pr e erve and pack.

Section

II TRIGGER GUARD ASSEMBLY

44 Removal and disassembly

Gages

55643-J-3

Refer to FM 23- 15 for removal

and

clisas

embly

of

the

trigger

guard

assembly (fig. 6).

45 Inspection

a

Geneml

.

In

sp

ect

all

parts

for

damage and

excessive w

ea

r

that

might

cause

malfunct

ion , burs,

ru st

foreign

matter

in recesses, deforma

tion,

and

free action with

mating

parts.

b

TTi

ggeT

Riveted) (

fig

s. 6

and

7).

Inspect

trigger for full action on

pin with res

pect to

guard. In pect com1ector pin

to

see if it is riveted

securely in place.

Rear

proj

ect

ions at

the

heel of trigger must be free

AGO 4471B


15/41

>

"

COUNTERRECOi

- Jib..

SPRING--:-5153133

J ECTOR-60

19639

MAGAZINE CATCH SPRING-5153 30

EJECTOR

5 0 2 2 2 2 5 ~ · · ·

EJECTOR

LOCK ' /

SPRING-5153132f

MAGAZINE

RELEASE-5022242

SEAR-5564299

\SEAR

RELEASE STOP

~ I J . £ V E R 6 1 4 7 4 8 7

; _

~ T R CONNECTOR-6019636

RA

PD

134734

Figure

6.

Trigger

Jnnrrl rt

s-Selli

ly

xplorled view.

of wear that would affect operation of safety. Top rear corner should

i.

Change

and

Stop Lever

Spring

Riveted)

fig. 6).

In

sp

ect

change

and


16/41

be s

harp, not

beveled,

at point

where it enters the notch in change lever.

In spect heel and tip for suffici

en

t clearance

with

bore of guard for full

ret raction.

c

Tr i

gg

er Connector figs. 6 and 7). Insp

ect top

bearing s

urfa

ce of

trigger c

onnect

or ·where it contacts sear

and

sear release

stop

lever. This

is a c

riti

cal surface,

as

excessive w

ea

r or

bur

s may affect function of sear

and

stop

lever.

In

sp

ect

r

ea

r toe of connector where it

contacts

tongue

in change lever apertme and fron t sloping surface sear carrier ramp) for

>Tear and burs. Profile must be clearly defined and all operating and

camming s

urfa

ces free of excessive wear

that

may affect functioning.

d. Sear

figs. 6

and

7).

In

sp

ect

se

ar

for looseness

orr

pin.

In

s

pect

sear

pin

for

urrclu

e wear

at

ends

and

for burs. i ear of

pin at

end is

in-

creased clue to movement in elongated hole in t rigger guard.) Inspect

sear for deformation, wear,

and

burs on forward lower ca

mming

sm·face

contacting connector

and

on r

ea

r upper camming s

urfa

ce contacting sear

release. Rear beveled camming smf ace must be perf

ect

ly smooth.

Inspect sear notch faces rear and top) for wear and bm·s. Sear notch

should be smooth

and

free from lmife or wire edge.

Not

e Sear pin holes in trigger

guard

and t rigger pin holes in sear car rier are

elongated to allow pl

ay

of mechanism, rel

at

ive to c

ounter

recoil

spr

ing, to absorb jar

of coun terrecoil on t he mechanism.

e.

Sear

Spring

fig. 8).

1) Dete rmine if sear spring is of latest desig·n. Modify sear springs

of early manufacture, which do not

have

the

2

-inch notch

at the rear

end,

to

conform

to the latest

design par. 46g).

2)

In

sp

ect

sear s

pring

for functioning

\Ti

t h sear an d connector,

looseness in retaining s

lot

s in trigger

guard

body, deformation,

fracture, and ea r. The two side prongs of s

pring

should bear

evenly on shoulders on fonYarcl

en

d of se

ar

.

Cente

r prong lies

below forward

en

d of sto p lever

and

b

ea

rs on forward

ramp

of

connecto

r. Prong

s are even

wh

en at

rest

and curved down

\rard. Forward end of spring should be well seated in its late ral

notch in trigger guard body.

f Sear R elease Stop Lever figs. 6 and 7) . Inspect sear release stop

lever for

\Y

ear

and

burs on forward lower s

urf

ace where

it

con

tac

t s co

n-

n

ect

or

and

on rear sm·face where sear release

st

rikes.

Rear

nose may

become expanded clue to ac tion of sear release and

thus

bind in sear.

g Sear Carrier Riveted) figs. G and 7). In spect sear carrier for loose,

fractured , worn, or

burred

connector

st

op riv

ete

d on

right

end) .

Inspect

connector caroming surface for wear a

nd

burs.

h. C

ha

nge L ever

figs. G and 7) .

In

spect c

hange

lever for functioning

with connector and trigger, def

orm

ation,

and

free movement in trigger

guard body should be close fit). The change lever moves freely in its

various positions, oper

ates

as

in ten

ded,

and

remains in the selected

position.

AGO

stop lever spring for functioning with change lever houlcl bear fi1·mly in

not ches) and sear release stop lever, deformation, and cracks.

In

spect

stop lever prong for fract ure, looseness on

ri

vet,

and

excessive deforma

tion,

cau

sing w

ea

k action on stop le

ver

.

j Maga

zine Catch figs. G and 7) . Inspect nose of catch for wear and

bur

s edge shou

ld

be sharp) .

Catch mu st

sec

ur

ely hold a

load

ed

mag-

azine.

lc Catch R elease fig. 6). Inspect magazine cat ch release for

free

movem

e

nt

in trigger

guard

body

and

catch, deformation,

and

frac

tured nose.

l

E.iectoT figs. 6

and

7). In sp

ect

nose of ej

ect

or for def

ormation

wear

and bms. Upper forward

co

rner of nose should be well d e f i 1 1 ~ d If

no

se is

bent

or worn, it fa

il

s to ej

ect

properly ;

i

too long,

it

binds on

bo lt and causes weak eject ion. It must fit the trigger guard body. t

must fit the trigger guard with sufficient freedom

to

pe

rmit

normal re

moval without per

ce

ptible looseness.

m .

Ej ec

tor Lock fig. 6) . Inspect ejector

lork

for free movement in

well in trigger guard

hou

sing.

n . T rigger Guard Body fig. G). In spect t rigger guard body for deform

ation, for worn

and

burred s

pring

r

etaining

grooves,

and

recei

ver

reten

Lon groove rear e

nd

). Trigger

guard body

assembles freely

to

the re

ceiver without appar

ent

looseness or s

id

eplay.

o

Counterrecoil, Ej ector Lock,

and

nfagazine Catch Sp1·ings

fig.

G).

In spect springs for function and fra

ct

ure.

46 Repair

a. General. Repla

ce

all broken, '01'11, or othenYise unserviceable

parts. R e

mov

e bms

and

ru

st as ex

pla in ed in p

arag

raphs 35

and 3G.

b. W ealc Ej ection. Weak ejec tion of cartridge case is caused by

th

e

neck of ejector scraping on bolt,

the

neck being bent or too short, or

the

nose being worn.

To

correct, grind off nose, being careful

to maintain

angle; st

raight

en or replace ejector. Space between ejector and

bolt

is

not more than

on

e thirty-second inch.

c. Slide Fai ls to Coclc

Thi s condition is

clue to damag

ed sea r, broken

se

ar

spring,

bm

s,

foreign

matt

er

in

sear notch in slid

e,

or failure of bolt

to

move far enough to the rear on recoil

movement to

cock

the

slide.

Examine

parts; cl

ea

n

and

replace

i

necessary.

d. Stoning Nose

of

SeaT. f nose of sear or sear notch in slide becomes

worn or burred, stone llghtly

with

a fine-grained sharpening

st

one. Ex

ercise care to

maintain retentive

angle and stone

to

polish only. f too

mu ch meta l is removed from top face of sear, the face becomes too s

hal

low to reta

in

slide,

clu

e

to

in terference of rear end of sear release cam

extension)

with th

e slide, t hus holclng sear notch out of engageme

nt.

Test sear r

ete ntiv

e action

after

sto ning, and i found questionable, re

place sea r. Dr ess in slide in like manner.

AGO 4471B

29

e. Correcting Trigger Pull

48 unctional

heck


17/41

1) uight t1·igger pull.

Light

trigger pull

is

caused by foreign matter

or

burs in

sear

notch

of slide

or

nose of ear .

Such

burs or·

foreign matter

prevent

nose of sear from seating fully in sear

notch

in

slide. To correct, remove foreign matter or stone

burred

surfaces

as

m

rpl

ained

in d

above. Replace

badly burred

or

damaged

p

arts

. A li

ght

pull is also due

to

a weak or

broken

sear

spring

that does not

seat the

sear fully

in the notch

in

slide; corr

ect by

replacing

sear

spring.

2) Excessive trigger pull. Excessive trigger pull

is

caused by bind-

ing on

components

of trigger group foreign

matter in

trigger

guard

body,

or

bw-s

on

t rigger, connector,

sea

r pin,

or sear;

correct

by

removing foreign

matter and

stoning bw-red surfaces.

f

Fitting

New

Trigger Gum·d. In fitting new trigger

guard to

receiver,

it

may be found that trigger

guard

retaining pin holes in trigger

guard

body

and

receiver are

not

concentric.

In

such event, stone off

rear

beveled surface of trigger

guard

or

mating

lug on receiver slightly to

aline holes.

Use

fine-grained

sharpening

stone.

g. Jl Iodifying Sea1· Spring .

File

row1ded notch in sear spring

with

small

rattail

Swiss

pattern)

file

to the

dimensions prescribed

in

figme 8.

The notch

facilitates

removal and redu

es breakage of

sear

spring.

3/64

/

R

\ ,

II

I

Figure 8. Filing notch

in

senr

sp1

·ing.

47 ssembly

Refer

to

Fl\11 23- 15 for assembly of

the

trigger guard assembly fig. 6).

AGO 4471B

a.

Inspect

trigger guard a:. embly for looseness, fw1ctioning,

and

co

functioning of its a sem blies

and parts.

Trigger

guard

assembly as

semb

les freely

to

receiver

without apparent lo

oseness or sideplay.

b. Check

fun

ct

ion of trigger, cmmector,

and

sear spring

with

trigger

guard assembly held horizontal,

tipped

forward,

and tipped

back. f

sea r spring is not bearing properly

on

forward shoulders of sear

and

center prong on connector, the connector will not ftmction properly

when trigger

guard

assembly is

tipped

.

Check

functioning of trigger,

ear,

and

stop lever, when change l

ever

is

set at

A position

norma

l cyclic

rate),

F po.-ition slow cyclic

rate), and

S

po

sition safe) fig. 9).

RAPD

910448

fi igw·e 9. Various posilio11s

of

change lever

on

assembled trigger guard assembly.

1) hange lever set at A (vertical position)

fig. 9).

When

change

l

ever

i

set at

A

po

sition

and

tl·igger

is

retracted,

the

connector

rai ·es

the

for\Ya.rd end of sear

and

sear release stop lever

to

gether and holds

them up as

long

as tr

igger is held fully re

tracted. Thus

the

rear end of the sear is depressed

and

held

from

engagement with sea

r

notch

in

slide, while

the

r

ea

r

end

of

sea

r release

stop

lever is also depressed,

preventing sea

r release

from striking caroming

smface

on rear

end

of

sea

r. When

trigger

is

released, sea r

and

sear release stop lever

both

return

to

their normal positions.

2)

Change lever set

at

fi (fonuaTd position)

fig. 9).

When

change

lever is

set at

F

po

ition

and

trigger

partially retracted, the

connector raises

the

fonYard end of sear

and

sear

re

lea e stop

lever together. As trigger is

further

retracted, the connector,

sti

ll

rising, is caromed from

under

front

of

sear by camming

surface on sea r carrier, and continues

to

raise forward

end

of

sear release

sto

p lever,

and

holds it in rai. eel position

as

long

as

AGO 4471B

3

trigger is held fully r

et racted.

Therefore, the sear is free

to


18/41

function when acted upon by

the

sea r release, willie the r

ea

r

end

of

the

·ear release

stop

l

ever

is depres

·e

d to a point w h n ~

it will not block

the

action of the

sear

release upon

the

carn

ming sw ·face of rear end of sea r. Thi s act ion produces the slow

cyclic rate of fire.

(3)

Change

lever

set at S (rear position

(fig. 9). When change lever

i . et

at

S po ·ition,

the trigger

is

blocked by

the

change

l

ever

and

prevented from

ri

sing, lifting the connector

and

disen

gaging

the

sca r.

49

Installation

HPfer o Fl\I

23- 15

for installation of t he trigger guard assembly.

Section Ill B RREL

AND RECEIVER

GROUP

50 Removal and Disassembly

a. RemoL a l of Barrel

Fr01n

Receiver (fig.

10).

I ) Only remove the barrel from the receiver when replacement is

necessary

or

for

gaging depth

of chamber.

(2 ) Place

barrel

in barrel holding

vi. e block

6316006

(fig.

4)

and

el

amp

n vi ·e .

Fit

receiver and barrel open end "Tench

6316005

(fig. 4)

on

receiver,

and

unscrew (right

hand

thread

receJver

from barreL

b. sassembly of Barrel Ass

em

bly

(fig.

11).

1) Kever remo\'e components

attached

to barrel except ·hen re-

placement

s are nece ·

ary

or for

the purpose

· of

sa

l

vag

ing.

(2)

Drive off front si

ght

blade, if neces ary

to

replace.

(3) Drive out the

front ight key

pin , ch·ive the front sight base off

to the front and remove the front sight key.

(4)

Drive

out ga cyli

nder

tub bracket pin and drive gas cylinder

tube

bracket off to the front .

c.

sa.

sembly of R

eceiveT

Group (fig. 12) .

1)

(2)

(3)

ide

the

operating handle

out

of

its

guides on

the

receiver.

Press

in on

the operating handle

plunger

and push out

t he op

erating handle

plunger pin

toward

the countersunk ide

of

the

plw1ger.

Then

remove the plunger and spring.

Lift the bolt gui de spr in g out of its sea t in t he bolt guide with

the rim

of a cartridge.

Remove the

guid

an

d spring from

the

rece1ver.

(- ) Depress change

l

ever sto

.p

spring

assembly until clear of groove

in change lever stop

spring retaining

pin , hake pin from re

ceiver , rotate ·pring down and push stop from

apert

m e

l

Jl

receiver.

AGO 4471B

AGO


19/41

>

Cl

0

B A R R E L

A S S Y 6 5 0 8 7 6 9 . .

FRONT SIGHT

BASE-6019630

FRONT SIGHT KEY

PIN-5022230

GAS CYL TUBE BRACKET--6019634

GAS

CYL TUBE BRACKET PIN

-502223

1

RECEIVER GROUP

(SEE

FIG

16)

Figur 11 BaTrel

rt

s mbly

e

p

lo

rl

rl

view

RA PO

134735

5) Buffer

tube

is

threaded into

receiver

and

is never removed ex-


20/41

cept for repl

acement or

repair. To remove, clamp receiver in

vise with lea ther jaws, first inserting buffer tube alinement tool·

spacer 7113328 fig. 4) inside faces of receiver

wa

lls to

prevent

springing of the receiver, and then unscrew buffer tube with

strap wrench fig. ).

STRAP WRENCH

UFFER TUBE ll NEMENT

TOOL SPACER-7113328

Fig ure 18 Removing btt:ffer tube

RA PD 91399C

6) I f necessary, remove

top pl

ate of receiver

by

driving out of

grooves

to

front of receiver, using a block of hardwood as shown

in

figure 14.

51 Inspection

a Ban·e

l

1) General inspection

In

spec barrel for deformation,

alinement

in

receiver, crossed threads, rust, co rrosion, wear , burs, and for-

eign

matter

in gas port and extractor ape rture. Barrel

must

aline exactly with receiver

vhen

assembled, in order

that

rear

end of gas cylinder tube will fit mating slot

in

receiver; front

sight will aline properly; and extractor aperture will be correct ly

positioned, drilled,

and

pinned during manufacture of

the

rifle

after barrel

is assembled to receiver. A

draw

mark is then

placed in barrel and receiver for proper alinement

upon

as-

sembly.

I f draw marks

do not qualify, fashion a shim from

shim metal.

7

(2) Inspection .foT sen iceability.

3)

f

barrel

and

buffer

tube

are

removed, insp

ect

for crossed

thread

s.

In sp

ect

bolt lock recess in top of receiv er for wavy. u r f a c e


21/41

(a) General.

In

pect

the

barrel (fig. 11 ) as a whole from

tandpoint

of servi ceabili ty. Before in pecting the barrel, a

ll

metal

and

other

fouling must be removed and the barrel

-ipeel

dry.

Acc

uracy

of fire is the main point to con:ider

when inspecting a

ba

rrel. Accuracy is reduced

in varying

degrees by bulge , ero ·ion, and pits in the bore. The extent

to which these defects ·ill reduce accur

acy

is determined by

two methods; namely, vi ual in spection and bore gagin

g.

b

l 'i

ual inspection.

For visuaJ inspection, using barrel reflector

72657

88

(fig.

-1),

hold the barrel so

that its

in t

erior is illumi

nated

and

examine the bore. f the barrel is not bent or

other -i ·e deformed, i the bore appears free from bulge and

large pit , and if

the land are

sh

arp

and uniformly distinct,

it is ervi ceable providing it i in good condition

othenvi

e.

A bulge i.

indicated

by a hadowy depres ion or a ring in the

bore. t may often be

detected

al o by a bulge or raised

ring on the e:-.'terior surface.

f

the barrel is pitted to the ex

tent

that the sharpn ess of the l

ands

i affected or if it h

as

a

pit or pits

in

the l

ands

or grooves lar

ge

eno ugh

to

perm it

pa age of ga aro

und

the bullet (that is, a pit the wid th of a

land or groove and three-eighth

inch

long or longer) t he

barrel w

ill

be

scrapped.

(c) Bore gaging .

Barrel i

ns

pected and found erviceable

by

visu

al

test will

be

bore-gaged, u ing breech bore gage 5564343 (fig.

3) .

Barrel

will be replaced if gage reading exceeds 0.310

inch in hands of troops in field or 0 .306 inch at

preembarka-

tion inspection.

b.

Gas

Cylinder Tube

mcl

c

et (fig. 11).

Inspect ga

cylinder tube

bracket for looseness on barrel, missing or loose pin, alinement of gas

por t w

ith

barrel por t, and for worn

or

burred dovetailed mating grooves.

(Br

acket

is a drive-fit on barrel

and

gas port is drilled t hrough

bracket

and barrel after assembly at manufactme.)

c.

Fmnt Sight }roup (fig. 11 ). Inspect

front

sight base for looseness on

barr

el ; mi ing, loose, or bun·ed

key;

a

nd

worn keyway (on barrel).

Insp

ect

for mi sing

front sight

k

ey pin

, looseness of pin

in

ba e, and for

looseness with key. I

nspect front

sight blade for position (stakes) ,

looseness in base mating dovetail, worn or

burred

dovetail (mal and

female), deformation, and shine.

cl. Receiver (fig. 12).

1)

Inspect

receiver for excessive wear, deformation (pinch

ed

sides

due to squeezing in vise), burs, rust, and foreign matter in re

cesses.

(2)

In

pee for loose rivets in bolt sup por ts and for cracks in barrel

end and bridge.

'

I

-±)

(5)

(6)

(7)

wear and burs especia

ll

y where lock seats when bolt

J

s locked .

~ c t surface by refl ecting l i g . h on

it

from a sma

ll

mlrror or a

bright too1.

This

surfa e i cnt1cal a nd afie?ts headspace.

In spect

to

p plate for looseness ( hould be dt we-fi t) ·

In spect buffer t ube for t igh tnes. on receiver. t

h o ~ l d

be free

of dents that would cause buffer cones and cups to freeze and

must contain eight ]Jlines. . . h ld

In sp

ect

receiv

er

for recess cut (fig. 15) · T h ~ · recess cut s. ou .

be ch·illed by depot

maintenan

e on all recmver. not hav g I

in accordance with

dra\\ing

D 6i:i3i:i373.

WITH

RECESS

I .

FiguTe 1

5.

Compm·ison of receiver with and without recess cut.

e. Operating Handle Group (fig. ~ 2 .

s p e c t

operating handl

e.

for

fun

ctioning and free

movement in

1ts slideway. In sp

ect p l u n ~

for

functioning and free movement in well.

In

spect plunger spnng for

fun

ct

ioning and frac tm e. .

f.

Bolt Guide Group

(fig . 12) . In sp

ect

bolt guide for

tioning

with

bolt, looseness

with prin

g looseness of

pnng

m rece

1ver

apertme and weak spring action.

g

~ n g e

L

ever

Stop Group (

fig.

12) . Inspect change

~ t o p

for

i o n i n g

with

s

pring

, wear, and

bm

s, s e n e s ~ on sp1.'mg (nveted) ,

and weak spring. In spect spring for looseness m recmver aperture.

In spect pin for looseness. . . . . .·

h.

Gas

Cylinder Tub e Retaining P

in

. e c t r e ~ l i l l 1 l g

p 1 ~

for spr.mg

re t

ention

with

depression

in

rece

iv

er, locking

functwn

of ~ e y

~

unde1cut

· · (left s

1

de)

In sp

ect

spring for looseness on pm (nveted), de

m rece1ver · · · · f ·r .

formation, or fracture. f spring becomes loose from

pm

, pm o ear 1e1

39

AGO 4471B

manufactme cannot be rotated to be withdrawn from receiver; however,

pin 5022232 of

latest manufactme

has a screwdriver slot on end for re

53 Assembly and Installation


22/41

moval of pin when spring breaks.

52 Repair

a. General. Replace all broken, worn, or otherwise unserviceabl e parts.

Remove burs and rust as explained in paragraphs

35

and 36.

b. Rep lacing Unserviceable Barrel.

1)

Disassemble barrel from receiver (par. 50).

2)

Assemble new

ba

rrel assembly, which includes front sight base

and

gas cylinder

tube

bracket. Screw up barrel until draw

marks

on barrel and receiver register . Assemble gas cylinder

tube to bracket; then check fit and alinement of rea r tang and

retaining pin holes in

tang

and receiver.

f tang

of

tube

does

not mate

without binding,

turn

barrel until this is accompli bed.

Barrel

·hould draw up

tight

ly

to

receiver so there is no possi

bility of vib rating loose. f there is no draw mark on barrel,

draw up until tube alines as above and check position of ex

tractor cut by assembling bolt with extractor assembled.

(3) f barrel does

not

draw up to proper position, ch·ess rear face of

shoulder

in

a

lathe

.

4) Never alter the receiver to obtain draw-fit. When barrel is

alined, check alinement of gas cylinder tube, front sight, and

extractor

cu t

.

f

barrel requires

much

shimming or dressing

to aline, headspace

may

be affected.

c. Front Sight Blade Out of Alinement . This is usually due to enlarged

dovetailed aperture in base. Peen lightly along upper edges aline sight

blade (by eye),

and

stake, using old stake mark. Base pin

may

be miss

ing; i so, replace and aline blade.

d Rough or Wavy Swface of Bolt Locking Recess in Receiver f surface

of bolt locking rece s in receiver is

bmred

or wavy, correct

by

removing ·

top

plate

(par. 50c(6))

and

-toning rough or wavy surface smooth with a

fu1e-grained sha rpening stone Exercise care to stone evenly and remove

as little metal

as

possible, as this surface affects headspace. Check

headspace (par. 27) after stoning.

e Loose Spring on Gas Cyl inder Tub e Retaining

Pin

f spring becomes

loose hom body of pin,

it

may be impossible to withdraw pin by ordinary

methods for replacement. In such event,

attempt

to revolve and shake

pin

out

of aperture or pull out with needle-nosed pliers.

f. Dents

in

Bu.tfer Tube.

Shallow dents

in

buffer tube are often re

moved by reaming with an expansion reamer et to the original inside

diameter of tube. Larger dents

may

be swaged out, first

by

using rod

the

size of inside diameter of

tube and

then reaming. f

dents

are deep

enough to cause possible weakening of wall of tube due to this procedure,

replace

the

tube.

Test

components in

tube

after repair for free move

ment

.

4

AGO 4471B

a. A embly

of

Receiver Group (fig.

12

).

(1) Install top plate, being careful no to deform the dov

eta

il.

(2)

In

stall bu

ffe

r

tube on

receiver as sho\\'·n in figure 20, being sure

that one of

the

eight groove in the head of

the

tube

li

e cen

trally horizontal with the top of the receiver with nose down.

'l

amp

re

ce

iver in vise, first inserting

the

pacer 7113328 (fig.

4)

of the buffer

tube

alinement tool 6316001 between inside faces

or receiver walls to prevent queezing of receiver, and insert

para

llel 7113327 fig. 4) of buffer tube alinement tool into re

ceiver,

\Yith

keyed end

toward

buffer tube end of receiver a.

shown

in

figure 16.

tart

the

buffer tube in to

the

ends of

the

receiver and inser plug 7113326

fig

. -± of buffer tube aline

ment

tool as shom1 in figure 16. Tigh ten buffer

tube

with

:trap \Yrench

until plug engages keyed end of parallel.

Note .

BufJer tube mu t be at t ightest possible position at which the

plug and pamllel 1\i.ll engage, u ing shim or h.ims,

i

ne es ary.

(3) In tall change lever stop pril1g assembly

in

re eiver

and

ecure

with change lever stop pring retaining pin.

4) In

sert

the

longer turned-over end of bolt guide pring in its hole

inside the receiver. Then install

the

bolt guide

and

hold it

while the spring is pushed over lmtil the horter t urned-over

end engages the groove in bolt guide.

5)

In

tall operating handle plunger spring (0.263-in.

0

D,

5

coil

)

in the

operating h

andle. In

sert operating handle plunger and

ecure with operating hanclle plunger pin. Be sme pin is in

stalled with ridge in colmter unk side of plunger.

6) In

ser operating handle group in i leway on receiver.

b Assembly of Barrel Assembly fig. 11).

(1) Install gas cylinder tube bracket, being sure to aline gas

port

holes. Secure bracket in place \\ith gas cylinder tube bracket

pin (0.1257 x 0.855).

2) Po

ition front sight key in groove on barrel and install front

ight base. Secure them in place ·ith the fron ight key pin

(0.0907 0

.5

05) .

3)

Install front sight blade

and

realine ights.

c Installing Barrel Into Receiver

(

fig.

10). When installing

the

barrel,

always be certain that it is tight enough

in

the receiver never to work

loose. Screw

the

barrel into the receiver until he draw line matches

that

of

the

receiver.

Then

assemble the gas cylinder

tube

to determine

whether the gas cylinder tube bracket on the banel alines properly with

the receiver, so gas cylinder tube rear tang slides easily into its aperture

in receiver.

f it

does not,

turn the

barrel slightly

until the

alinement is

correct. hen assembled, check extractor

cut

in rear face of barrel for

position. For assembling new barrel, refer to paragraph 52.

AGO 4471B

41


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(1957) tm 9-2111-1 field maintenance cal. 30 browning automatic rifle m1918a2

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