8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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.
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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4
0
a
AGO
H71B
'
'
.
...
0
a
AGO
4471B
:;;
...
'
53
..:::.
- '
;..
;,
2
-.
:::
-
-:
':::.
. -
....
g
<
' '
::;
,
s
0
i
t
5
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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'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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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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
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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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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)
\\
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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-
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
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
8/16/2019 (1957) TM 9-2111-1 Field Maintenance Cal. 30 Browning Automatic Rifle M1918A2
23/41
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