One subject that comes up frequently is how to identify barrels on various models of
ground typeM1919 BMG’s. All of the numbers, letters and symbols
imprinted on the barrels have meaning . We hope to shed some light on this subject
by offering the following observations.
article limits it’s scope to ground types, that is only those M1919’s that were
used in ground operations which would include infantry, cavalry, armored units,
air cooled members of the .30 caliber Browning Machine Gun family have a common
ancestor 1n the M1917 water cooled “Heavy”.The M1917design was modified late in WWI into a 18 inch
barreled air cooled weapon for use in tanks and was actually called the Model of
1919 Tank Machine Gun. WWI
ended before very many of these weapons were produced.The manufacturer of the air cooled tank gun, New
England Westinghouse, saw their contract shrink from 40,000 to 10,000 to about
doctrine used machine guns, primarily, for defensive applications as they tended
to be water cooled, very heavy and were mounted on equally heavy wheeled or
stationary tripod type mounts.
The weight of the mount and the weapon produced an
extremely stable firing platform, and many times machine guns were viewedin almost the same context as artillery, right down
to developing methods of indirect fire and machine guns in U.S. service being
organized into separate battalion level units in divisional organization.
were some attempts to produce lighter air cooled automatic weapons for use in
the attack, the Lewis Gun, with it’s signature circular horizontally mounted
magazine and stove pipe barrel jacket and the M1918 Browning Automatic Rifle,
both were successful designs.
They were light enough to be carried by one man, and
had the ammunition supply attached to the weapon.However, even though the Lewis had a magazine
capacity of 47rounds, over twice the capacity of the BAR frequent
changing of magazines reduced their effectiveness.
There were also less than successful attempts to
produce an automatic weapon for the attack, most notable was the infamous FrenchC.S.R.G. (Chacuchat)The politest thing one couldsay about this poorly designed and equally poorly
manufactured weapon was “not combat reliable”.
The U.S., being desperate for automatic weapons
purchased about 19,000 in caliber .30’06 and used virtually none. Reportedly,
U.S. troops refused to carry them into combat.
was really needed was a rifle caliber weapon more portable than the water cooled
“heavies”, yet still capable of some level of sustained fire, that couldbe more easily advanced with the attacking infantry.In short we, and everybody else, needed a rifle
company, rifle caliber automatic weapon.
Following the Armistice, on November 11, 1918 the United States rapidly reverted
to it’s isolationist policies and historical aversion to a large standing army.
The military forces shrank nearly to pre WWI levels,
budgets were slashed and weapons development nearly disappeared.
If any one branch of the
pre WW II Army is to be credited with development of the 1919 air cooled ground type BMG
into a viable weapons system, it’s the Cavalry.
The Cavalry, still horse mounted, was attempting to
remain relevant in a rapidly mechanizing environment, and realized that some
sort ofreadily portable automatic weapon was necessary to increase
the combat power of mounted troops.
Their first choice was a modified BAR, the M1922, apparently
this wasn’t exactly what they had in mind so they switched
gears and in 1930 acquired a M1919 tank machine gun and jury
rigged some sights, developed a tripod
mounted to the weapon by the pintle mounting hole in the trunnion rather than a barrel jacket clamp like
the original tank dismounted tripod, and presented it to Ordnance as a prototype
of what they wanted.
the Ordnance committee recommended
that the “Machine Rifle Cal.30 M1922” be declared obsolete on April 10, 1941.Sometimes it takes a while, in this case 11 years,
for even things that aren’t required to work their way out of the system.
1931 the Infantry followed suit and began to experiment with an air-cooled
weapon.Both the cavalry weapon which became the M1919A2, and the
experimental infantry weapon which became the M1919A3 were equipped with the 18
inch barrel and slotted barrel jacket from the tank gun.When the tank gun was developed in 1918 Ordnance was
using the Class and Division system of numbering drawings and the 18 inch barrel
was shown on drawing 51-18-5C.
M1919A2’s barrel’s assigned “piece mark” was 5A1 on this drawing.Other parts of the barrel assembly, the “muzzle
attachment“ (front barrel bearing) and the “muzzle attachment plug” (booster
plug) , along with the barrel jacket and barrel jacket ring were shown in other
details on sheet 51-18-5 .This drawing detail was renumbered on June 1, 1931
is detail D of drawing 51-18-5 showing the M1918 tank gun barrel jacket with the
elongatedcooling slots that remained with ground type air cooled
BMG’s until 1939.On June 1, 1931 all of the original 51-18Tank Gun drawings were redrawn and converted to the
letter prefix system which had only one part to each sheet.This drawing became C9819.
Ordnance seemed to use the term “tracing” interchangeably with the term
“drawing”.Actually, “tracings” were made with India ink on linen
cloth or velum which is a
translucent hard finish medium similar to parchment paper.The tracings were used to produce copies of the
drawings by the “Blueprint” or "Brownprint" process where a specially treated paper was
moistened, covered with a clear glass plate, which was then covered by the velum
tracing and another glass plateand exposed to light.
Light, acting on the
chemically treated paper through the tracing, produced a sort of negative image where the dark
lines on the tracing became white lines on a dark blue or brown background, hence the
name “blueprint“ or "brownprint".
For some time this was the only practical method available to
make duplicate copies and, it remained in use into the early 1960’s.Occasionally, even today, you will encounter a
“blueprint” style drawing copy especially in land survey documents dating before in the
the term “blueprint” has a totally different meaning. In automotive parlance
“blueprinting” describes an engine that has been carefully assembled with
specially selected components.In common use, “blueprint” or “prints” means any
sort of drawing used to construct, or fabricate anything from a birdhouse to a
Later in the
article you will see an actual “blueprint” copy of a barrel jacket drawing.
the Class and Division naming convention automatic weapons were identified as
Class 51.The M1917 was a Division 10 and the M1919 tank gun was
Division 18.When the Class number was combined with the Division
number, it produced a Major Item Number.In this way the M1917’s Major Item number was 51-10
and the M1919 tank gun was Major Item 51-18.
few parts produced during and immediately after WWI were required to have the
piece mark imprinted on the part, however, they were usually marked with the
manufacturers symbol, and certain parts namely barrels, bolts and barrel
extensions were required to be proof fired with special high pressure test
cartridges. These parts were marked with a proof mark, an upper case “P“, and
the world famous Ordnance “Flaming Bomb” property/acceptance mark.
The original 18 inch barrels for the tank guns were
produced by New England Westinghouse and they weremost likely marked with a W in a circle.This policy of not marking the all of the parts with
the piece mark continued well into WWII production.Some of the parts, even large parts like the barrel
jacket, were never required to be piece marked, however somejackets may have been.
The marking, or lack thereof depended on the whether
or not the drawing required the part to be marked, and in what location and,
apparently, the whims of the manufacturer.
Saginaw Steering Gear Division of General Motors,
the all timeM1919A4/A6 production, quality and price champion must have
issued a “flaming bomb” stamp to nearly every one in the factory and encouraged
their use.Saginaw built weapons have “flaming bombs’ everywhere.
Drawing B169913 which was not a drawing of a part at
all, contained tables showing which M1919A4 parts were required to be imprinted
and the authorized manufacturers codes.
markings were not always applied in the locations specified on the drawings.
seems to be the air cooled Cal.30 BMG’s watershed year, the Rock Island Arsenal
completed production drawings for the M1919 family, both the Infantry, and the
Cavalry who were busy trading in their steeds for scout cars, had concluded that
a 24 inch barrel was better suited to their needs, and the decision was
finalizedto convert some excess M1917 water cooled BMG’s left over
from WWI, the few M1919A2 Cavalry models, M1919 tank guns and any other
experimental weapons lying aroundto the new air cooledM1919A4 weapon.
Rock Island Arsenal publication titled “NOTES ON THE BROWNING MACHINE GUN CAL.30
M1919A4” dated March 18, 1937 set forth everything that you needed to know about
the weapon conversion program right down to Section VIII Paragraph 2 which
instructs which type of lubricant (class A or Navy contract oil 2110) and
cautions that the “Bolt, barrel guide, extension and other moving parts should
be cleaned if practicable and be lubricated after firing not more than 10,000
10,000 rounds seems like a lot, especially with corrosive
primers, that’s 40 M1 Ammo boxes with 1-250 round belt per box.
2 of the 1937 “NOTES” document has a great right rear quarter photo of a early
non-production prototype M1919A4 rebuilt from a New England Westinghouse M1917.
A-typical M1919A4 complete with M1917 style trigger latch ("safety") back plate,
slotted barrel jacket, new flanged bottom plate with integral T&E attachment and
a finger flanged offset bolt latch required because of some sort of reinforcing
applied to the rear of the side plates.This additional side plate reinforcement was likely
replaced by the later heat treatment of the rear mostinch or so ofthe production side plates.
This photo also shows new sights, and the spring
clip on the bottom of the pistol grip.Note that the bottom plate flange rivets are ground
flat andare not the later dome head style. This document is the
first mention of the assignment of a Major Item identifier of 51-83 for the
Fixed and 51-84 for the Flexible M1919A4 weapons.
document also stated that it was to be considered to be the “instructions to the
using services until a S.N.L. could be prepared.”
29, 1938 brought an addendum to the original “NOTES”this one was titled “NOTES ON THE BROWNING MACHINE
GUN CAL.30 M1919A4 MODIFIED”which dealt with a few refinements in the design of
the belt feed lever,a .047 wire driving spring combined with a .617 inch
hole in the booster plug changing the rate of fire to 500 to 600 RPM, dome
headed style rivets to secure the rear of the top plate, and modifications to
the hold open feature of the top cover.
FIGURE1 from the “Modified” notes looks more like what we
are used to seeing except for the slotted barrel jacket.This photo still shows the M1917 style trigger latch back plate.
Note the dome head rivets securing the bottom plate
to the side plate.The driving spring and the .617 booster plug were
Ordnance Technical Committee meeting#46 on November 10, 1938 discussed Item 14772 which
outlined tests of, and made a final for the record recommendations for the
substitution of barrel jackets with round holes for the slotted type.The Committee concluded that the jackets with round
holes cooled just as well, were easier to fabricate, were stronger, and had a
satisfactory record on M2 Aircraft BMG’s.
1919 BMG ground family includes the M1919A4, Fixed and Flexible, the M1919A5
Fixed, the M1919A6 Flexible, M1919A4E and post-war the M37.All of these weapons with the exception of the
M1919A6 used the same barrel designs.
WWII era producers of what was to be officially known in the 1940 dated Field
ManualFM 23-45 as the “Browning Machine Gun, Caliber .30, H.B.,
M1919A4, Ground” were:
RIA,Rock Island Arsenal, Rock Island, IL
SG, The Saginaw
Steering Gear Division of General Motors Corporation, Saginaw, MI
Some parts, but
not barrels, likely produced at Saginaw’s Grand Rapids, MI plant are marked S.G.
BA,(BAC has been reported) Buffalo Arms Corporation,
Buffalo, NYBuffalo Arms was a subsidiary of the Houdaille-Hershey
Corporation formed solelyfor the production ofarmaments during WWII.
(BC has been reported) Border Cities Industries, Windsor, ON, Canada.Border Cities was a GM, Canada subsidiary which
manufactured M1919A4’s for British Commonwealth countries, chiefly Canada.
the manufactures ofthe Caliber.30 air cooled ground family of BMG’s
also produced barrels marked with their identifying code.
Machine gun barrels, especially in air cooled weapons, wear out rapidly.Heat and friction are the enemy of any mechanical
device, and machine guns are no exception.Each four man M1919A4 team carried an extra barrel
and a set of asbestos barrel changing gloves with each weapon.Each manufacturer supplied great numbers of
replacement barrels.SNL A-6 dated May 28, 1941 called for 400 spare
barrels per 100 weapons for one year in a theatre of operations.
In addition to
the prime contractors, several other companies supplied barrels:
GL, The Guide
Lamp Division of General Motors Corporation, Anderson, IN
been reported that General Motors Corporation, Detroit, MIunder their corporate name, and The Crane Company, a
Chicago, IL manufacturer of plumbing fixtures, also produced caliber .30 air
cooled barrels.It is not now known what manufactures code were used
to mark thesupposed GM and Crane barrels.It is well known, however, that the Crane Company
was an early experimenter and producer of “Stellite” bore liners for Caliber .50
By 1936 when
the M1919A4 design was more or less finalized, Ordnance had mostly converted the
numbering of the actual drawings used to fabricate parts from the old Class and
Division system to the letter prefix system. In 1922
Ordnance, using the experience gained from WWI, implemented mandatory physical
sizes of the medium the drawings were prepared on.They are:
Size A=8 1/2X14
Size E= 40X necessary length
the M1919A4 was a “new” weapon at least from the trunnion forward, the barrel
drawings started with letter prefix drawing number D35233 datedSeptember 30, 1936.The drawing shown below went through 14 Revisions
the last, Revision 14, was dated 4-7-42.
Class and Division and letter prefix drawings showed a “piece mark”, which after
1943 was supposed to be called a “part number”, but in practice was not.The piece markis the identification for the part (s) shown on the
drawing.While each part had a piece mark, not every part was
required to be marked.The drawing for the part, even in the old Class and
Division system of numbering drawings, indicated how, where, and in what size
the part was to be marked.
drawing above requires the piece mark of D35233-14 to imprinted longitudinallyon the barrel about midway between the muzzle and
the chamber in 1/16 inch characters.It also requires that the “P” indicating that the
barrel had been proof fired, be imprinted in 1/8 inch charactersabout 4 inches and 90 degrees clockwise, as viewed
from the chamber end.From the drawings observed this is the standard
locationprescribed for marking barrels.As we will see later, the barrels were usually not
marked in the locations specified on the drawings.
Besides the piece mark, and the firing proof mark the barrels were supposed to
be marked with the manufacturers identification, the ordnance flaming bomb, and
were usually marked with several other letters or symbols most likely to
identify which production line and company inspector produced and inspected the
barrel.This marking would come in handy to track down the source
ofbarrels that were rejected by government inspectors.
The location of
the flaming bomb and the production markings varied, but the manufacturer’s
identification was usually near or directly following the piece mark.
is some confusion regarding the appearance of the piece mark on M1919A4 barrels
and other parts.The required piece mark is D35233, however the mark
D 35233 and
D-35233 all with
various Revision suffixes have been observed.
my examination of available Ordnance records there is no significance to spaces, dashes, or lack thereof.These differences are, in my opinion, either some random
event that varies even with the same manufacturer, or stems from the fact that
sometimes Ordnance drawings added a dash or space, even though there dashes and
spaces were contrary to Ordnance practice, between the letter prefix and the
first numeral in the drawing number
The piece mark
suffix numbers observed on M1919A4 barrels are D35233-6, D35233-12 and D35233-14
these suffix numbers represent Revision numbers on the D35233 drawing.
Not every revision to the drawing
generated a change in the piece mark. The changes to the
piece mark were authorized by "O.O." serialized
letters from the Office of the Chief of Ordnance and listed
on the Draftsman's Work Order that changed text or
dimensions on the drawing.
The exact criteria for a piece mark
change has not been determined as of yet by the author.
is a photo of a Saginaw Revision 6 barrel.The firing proof “P”is located directly below the “G” in SG , the ever
present flaming bomb is just visible below the “23” in the drawing number.The two C’s are likely factory markings used to
identify the production source of the this barrel which is shown in it’s
original finish. Note the space after “D”.
Revision 6 dated
10-3-40 apparently had to do with changing the quality of the finish of the
barrel between the bearing surfaces, and subsequently changed the piece mark to
original, that is the unrevised,barrel drawing contained a detail drawing of both
the chamber and the barrel rifling.
Revision 12 dated 11-28-41, with piece mark
D35233-12removed this detail by crosshatching and added“NOTE: FOR CHAMBER AND RIFLING SEE DWG. C64321.”
This was probably done to remove the possibility of
different drawings with slightly different dimensionsbeing used to cut chambers and rifling in different
The C64321 drawing became a single “go to” reference
drawing for everybody cutting chambers and rifling barrels at least for BMG‘s.This would add another level of uniformity to the
very critical business of chambering and rifling weapons all using the same
ammunition designed to function in all weapons.
photo shows a refinished Saginaw Revision 14 barrel.Note the dash between the D and the drawing
numerals.The firing proof is located below and to the left of the D,
the flaming bomb is can be seen about ½ inch below the SG and the lower case “c”
factory mark about 1 inch to the right of the SG.
All markings are 4 inches from the chamber.Some barrels are marked on the long axis of the
barrel, like this example, while others are roll marked on the circumference of
of “rdulina” 1919a4.com forum.
Buffalo ArmsD35233-14 barrels.Note the dashes between every part of the imprinted
piece mark.There is no apparent rhyme or reason for the dashes as they
follow no pattern and have no known meaning.
Many Buffalo Arms barrels have the circular tool
marks that are prominent in this photo.
final observed piece mark D35233-14 was a result of Revision 14 dated4-7-42 this revision does not appear to have
accomplished much of anything except change the piece mark.
September 30, 1936 to 4-7-42 very few dimensional changes besides a few minor
tolerances changes were made to the barrel, other than the chamber detail which
was removed by Revision 12.
In any event, the barrels, regardless of suffix
markings, manufacturer’s identification marks or miscellaneous inspection and
production stamps are fully interchangeable among the various 1919’s except for
the M1919A6 which used a different barrel design in an attempt to reduce the
weight of the recoiling parts so no booster would be required and the barrel
could be changed from the front.
SNL's never listed the revision numbers as part of either the drawing
number or the stock number.
If you have a
barrel marked D35233 it was made after September 30, 1936 and before
barrels were produced after 10-3-40 and before 11-28-41.
D35233-12 marked barrelswere produced between 11-28-41 and 4-1-42
D35233-14 piece mark indicates a production date between4-7-42 and5-10-48 when the drawing D35233 by Revision 22 was
converted to the 7 digit naming convention and became a D size drawing numbered
6535233 and changed the part number (piece mark) to 6535233.
of clarification is in order.The production date spans quoted above are not
absolute they only state times in the past tense.That is, a D35233-6 barrel could not have been
produced BEFORE10-3-40 because there was no drawing authorized to
mark it as such.
However, just because the Revision 6 appeared on
10-3-40 doesn’t mean that D35233 barrel production halted and the next day
resumed with D35233-6 barrels.
There was some unknown time lag between preparation
and approval of the drawing, dissemination of the drawing and actually
implementing changes to the part and to the associated piece mark.
If a producer of
barrels didn’t get the new drawings they just kept producing barrels from
whatever drawings that they had on hand unless someone told them not to. Even if
the manufacturer received the drawing in a timely fashion, it took some interval
to get the work force on board or even make up a new die stamp.
There is likely
considerable overlap in the production dates of piece marked barrels with or
without revision suffixes.
all of the manufacturers of the M1919A4 produced barrels only Saginaw and RIA
produced A6 barrels during WWII with Saginaw being the only WWII producer ofpurpose built complete A6 weapons.The drawing D54559 dated July 27, 1943 is the first
incarnation of the A6 barrel.
one looks at the subject of barrels for the 1919 family, the question of barrel
jackets invariably comes up.The air cooled BMG’s require a jacket to support the
front barrel bearing surface that supports the weight of themuch heavier barrel required by the absence of a
water cooling system.
The M1917 water jacket assembly contained an
integral support for the front of the much lighter M1917 barrel.The original A2 and A4 slotted barrel jackets had
the barrel locking screw hole and it’s associated trunnion threaded screw hole
located on the top of the barrel jacket and trunnion.While this location was just fine on the A2 with
it’s front sight located on a band on the barrel jacket near the muzzle, it wasblocked by the front sight located on the front of
the trunnion in the production A4’s.
With the adoption
of the round hole barrel jacket these holes were relocated
to the right side of the trunnion block and jacket. In 1942
the barrel jacket to trunnion assembly required that the jacket be
sweated to the trunnion threads with “Minimum 500 degree F” solder in addition to
the locking screw being staked in place.Barrel jackets were never officially required to be
imprinted with piece mark/part numbers.
dated January. 18, 1936 is the earliest dated drawing we have discovered that
depicts a barrel jacket with round cooling holes.The next drawing of the jacket is C62503showing slotted jacket with a date of January
undated drawing, or rather blueprint copy of drawing C9819 is the earliest
indication of a barrel jacket for theM1919A2E3, the experimental 24 inch barrel version
ofwhat would ultimately become the M1919A4.It appears that a blueprint copy of drawing C9819the 18 inchbarrel tank gun jacket was made and hand notes
indicate the new length, 19.08 (-.002) and the new drawing number C45950.
The two vertical wavy lines intersect the jacket
between slots indicating a break in thepart drawing.
The note to the left says “add
additional slots for additional length”.In the upper right hand corner of theC9819 drawing blueprint copy, the number and date
were lined out and the hand written notation “New Part”was entered.In the “Drawing Pertains To” block, the notation
M1919 tank gun was lined out.
Copying a drawing, and making hand notations to
indicate changes to be made is a common drafting practice.
where things get really murky.Even though the above drawing indicates that the 24
inchbarrel version of the slotted jacket was to be shown on
drawing C45950, the earliest version of that drawing dated 1-18-36, shows round
holes instead.However the unrevised, version of Drawing C62503,
dated 1-20-36 shows slots until Revision 2 dated 9-6-39 when the slots became
Both the original C62503 drawing showing slots and the C45950 that was
supposed to show slots but had holes were superseded, by theC62503 Revision 2 drawing.Notations on C45950 also indicate that it was
superseded by C62503 on 9-6-39.
We are unable to explain the discrepancy in the
dates.If C45950 was earlier, why didn’t it show slots?
Conversely, if C62503 was later why did it have the slots, being later it should
have had round holes one would think?
C62503 originally dated January 20, 1936 showing the early slotted jacket.The legend at the bottom notes:“SUPERSEDED BY NEW TRACING C62503 UNDER REVISION
DATE OF Sept. 6, 1939”With a wave of the Ordnance wand, the slots
disappeared, and the holes appeared and the drawing number remained the same.Houdini couldn’t do this good.
explanation for all of this is, that after the Ordnance committee
recommended the change from slots to holes on November 10, 1938 it was decided
to substitute the C45950 round hole jacket drawing for the C62503 slotted jacket
to avoid having to have to change all of the documentation that had already been
This would work because theDRAWING NUMBERS would remain the same, but the
actual part depicted would change.
SNL A-6 dated May 1941 still shows a slotted jacket
on the A4 with the drawing number C62503 and SNL A-6 dared September 1943 shows
the round hole jacket WITH THE SAME C62503 DRAWING NUMBER as the 1941 version of
We do not know why it took from the Ordnance Committee
meeting on November 10, 1938 until September 8, 1939 switch the drawings around.
C62503 REV 8, dated
1-18-43It is difficult to see but This starts with REV 2 dated
9-8-39There is no REV 1.REV 2 swapped the C45950 jacket with holes for the
C62503 jacket with slots.The respective parts remained the same, but the
drawing numbers were changed or superseded.
is a copy of drawing (C)5562503 REV 9 the M1919A4 barrel jacket.REV 9, dated 5-10-48 changed the drawing number from
C62503 to the “new” 7 digit format and also changed the part number (piece mark).This is the last version of the drawing of the
M1919A4 barrel jacket that we have been able to obtain.
Drawing C93962 dated July 22, 1943 is the earliest version
of the M1919A6 jacket it’s overall length is 16.584 inches.This jacket was designed for use with the earliest
version of the M1919A6 which lacked a booster.
The note on the very
bottom shows the successor drawing number C7160455.
Drawing(C)7160455 with no revisions is the last and shortest
(15.954 inches) of the A6 barrel jackets.This version replaced the earlier and longer A6
jacket depicted on drawing C93962 above.The original drawing date is March 21, 1944.The 7 digit drawing starting with 7 indicates that
this drawing shows an all new part which is not interchangeable with the earlier
version.This jacket is intended to be used with thelate WW II style two piece booster cap/bearing
which was developed after it was discovered that the earlier M1919A6 without the
booster did not function reliably under combat conditions.
drawing isn’t a drawing at all, it’s a list of the parts of the M1919A4, A5, and
A6 which are required to be marked.It also contains a list of the manufacturers
identification marks.Note that only three of the listed manufacturers
actually made M1919’s .
Under the component list line 14 and line 18 are
blank. Originally these lines contained the rear sight spring on line 14 and the
alternate design of that spring on line 18.
Revision 8 dated 7-22-43 to this drawing removed the
requirement that these parts be stamped with the manufacturers identification.
The list of manufacturers may have been a generic
list created pre-war because Ordnance didn’t know which companies would be
The date on the original drawing is April 7, 1941 8 months before
the U.S. declared war.
12 of the1942 Base Shop Data book for the 1919A4 Overhaul section
outlines the prescribed method of aligning the barrel jacket with the “receiver”
Thisalignment operation consisted of placing the casing
with the barrel jacket andfront bearing attached in an alignment fixture
checking alignment with gauge “C”(shown on drawing C16315) and if required “ Withdraw
from alignment frame and, grasping the receiver, strike the barrel jacket
sharply on a lead block on opposite side to the binding surface.Replace in alignment frame and check with gauge C.Follow this procedure until perfect alignment is
Gauge C is a sort of mandrel passed through the rear
of the casing with alignment surfaces for the front barrel bearing, attached to
the barrel jacket, and the rear barrel bearing in the trunnion.
Somehow this procedure, which falls under the category of “If it doesn’t fit,
find a bigger hammer”school of machine shop operating practice,is notnearly as technologically advanced as I expected it
to be.I thought there would be some big press that would
straighten out the whole works. I was wrong. Basically, the person doing the
assembly beat the
jacket into alignment.
11 of the Dismantling section of this same BSD has
a note “These jackets are not interchangeable and should be kept with the
original receiver”This may be one of the reason that the practice of
sweat soldering the jacket to the trunion was initiated.
Sweating the parts together would preclude the
jacket being separated from the casing during casual disassembly.Sweating would also prevent the jacket from
unscrewing itself in the event that the locking screw fell out.
air cooled barrel jacket is nothing more than a steel tube with internal threads
at both ends, the casing end having a longer threaded portion, a hole for the
jacket locking screw, and the muzzle end having a notch for staking the front
barrel bearing/ booster locking band .
It is equipped with holes for air circulation to assist in
cooling the barrel itself.
The only mechanical purpose of the barrel jacket is to support the front barrel
bearing which supports the muzzle end of the barrel, although it also provides
the operator with some protection from contacting the hot barrel.
The drawing C62503 shows a 19.08 inch length for the
M1919A4 jacket which remained unchanged from the adoption of the 24 inch barrel
until the end of production. Drawing C62503 Revision 9 dated 5-10-48 changed the
drawing number to (C) 5562503 and part number (piece mark) to 5562503. The
earliest versions called for seamless tubing, but this requirement was changed
by Revision 6 dated 6-18-42 to allow tubing with an electrically welded seam.
cut is from SNL A-6(Standard Nomenclature List) dated September, 1943
and shows the barrel group parts for the A4 andthe early A6.The development of the 1919A6 starting in late 1942
required a completely different barrel and a slightly modified jacket design
because of the addition of the bi-pod head.
The bi-pod head mounting required a longer
booster/bearing. Early A6’s used a shorter barrel jacket, C93962 (16.594 inches
long) to accommodate the length ofthe B261109 one piece bearing with no booster
supporting the bi-pod head which was secured in place using the A238235 (snap)
The A4 barrel group parts, other than the development of a
one piece bearing/booster, M6 flash hider, and Stellite barrel assemblies remained virtually unchanged
until production ended.
July 22, 1943
seems to be the date of the A6’s official adoption as that is the original
drawing date on most of the A6 drawings.
cut from ORD 9 SNL A-6 dated April, 1947 shows the late type A6 barrel group
parts.Note that all of the parts except for the locking band
A170491 have different drawing numbers from the previous illustration.
This barrel group uses a different, even shorter
jacket, Stellite barrel, two piece front bearing/booster cap, and bipodhead retaining parts.These parts, other than the band and barrel, are NOT
completely interchangeable with the earlier parts.
The same document lists two different A6 casing
assemblies D35358 “for guns of early manufacture” and D7114037 for the later
style.The “7” prefix on the (D)7114037 drawing indicates
non-interchangeability as it is a post 1943 “new” part/ drawing number.
The only difference in the component parts of the
different casingassemblies is the barrel jacket, and a typographical
error in the list of components for the late style D7114037 casing assembly that
incorrectly describes the A20527 breech cam block screw as a rivet.The C7160455 jacket which was the final A6 jacket
design was adopted on March 21, 1944 andit is 15.954 inches long.
confusing aspect of M1919 barrels is the term “Stellite barrels”.Stellite is the trademarked name of a non-ferrous,
cobalt-chromium alloy often combined with various other materials to produce the
developed by Elwood Haynes in the early 1900’s.The trademark name “Stellite” is the property of the
Deloro Stellite Company.
Stellite alloys come in a variety of compositions
depending on their intended use.One common use for Stellite was valves, valve guides
and valve seats in internal combustion engines. Some Stellite alloys have high
melting points, and extremely high wear and corrosionresistance making them very useful for applications
like a machine gun barrel.
Because of Stellite’s wear resistance it is difficult to machine, usually the
part is cast to near finished dimension and ground to final specifications.Parts made from Stellite are expensive to produce,
however, by using the Stellite parts in high temperature/wear areas in
combination with other less expensive and more easily fabricated materials like
steel, the useful life of the assembly can be extended several times.
Thebore area just ahead of the chamber of a machine gun
is subject to repetitive intense heat and friction, and in addition, prior to
about 1954 when the U.S. Army’s service ammunition primer composition changed, caliber .30 weapons
were also subject to the corrosive effects of hydroscopic salts produced by
Ordnance began experimenting with Stellite barrel components for the Cal.50 BMG
in 1942, however, progress on developing and adopting Stellite for barrel use
dragged on until 1944 when a workable process to produce aStellite bore liner for the Cal.50 BMG was
developed.This liner, in combination chromium
plating the bore and exterior bearing surfaces produced barrels that had a
useful service life 300% greater than standard barrels.
excellent results had been obtained using the Stellite/chromium
plated Cal.50 barrels it was decided to apply a similar process to Cal.30
barrels for the M1919A6.
The A6 was chosen, because it’s lighter barrel, it
weighed about 4.8 lbs versus the A4 barrel weight of 7.47 lbs. caused it to wear
faster than the A4 due to it‘s inferior heat dissipation ability.The decision to make Stellite barrels the preferred
A6 type was not reached until July of 1945, this would preclude very many, if
any, Stellite A6 barrels from service use during WWII.
earliest type of Stellite A6 barrel is shown on drawing D7162295.This drawing is of a barrel assembly consisting of
the liner (the Stellite bore insert) C7162479, retainer (the
steel chamber insert screwed into the tube) B7162480, the tube ( the steel
barrel itself) D7162478, and a pin which locked the retainer in place, BFDX1.
Note that all of the parts other than the pin, a
standard part, have successive drawing numbers.The barrel was only available as an “assembly”.The individual parts making up the assembly were
not.This early type barrel assembly did not have a chrome
plated front barrel bearing and chrome plated bore ahead of the liner.
Stellite barrels can be easily identified, other than looking at the part number
imprinted on the barrel, by carefully examining the chamber end.The seam between the steel retainer and the barrel
tube and the dimple from the locking pin are clearly visible.
first mention of a Stellite barrel assembly for the A4 that we could findis in ORD 7 SNL A-6 dated October 1951.This lists the assembly drawing as D7162785.
Changes No. 1 to this document dated February, 1952
still shows the D35233 (now called 6535233) standard A4 barrel andthe D54559 (now called 6554559)the standard A6 barrelwith a note that the standard barrels were to be
issued untilthe supply was exhausted and only then would the Stellite
types will be issued.
This seems to make sense, since the Army, most
likely had, literally, tons of the standard barrels on hand and was wont to not
waste anything in a tight budget post war era.
of Tom Pfremmer
A4 and A6 Stellite barrels were paint stenciled in addition to being
imprinted with the piece mark (part number), or in this case drawing/part numbers on this last model RIA
A6 barrel.Even though Ordnance started to implement a 7 digit
drawing/part/stock number system in 1943, the habit of using the drawing size
letter that was supposed to be eliminated with the all digit system died hard.
The reason for this is the drawings were still
prepared on, and filed by, the various letter sized sheets originally mandated
of Rollin Lofdahl
This picture shows thepart number and the date of manufacture 1-67 of the
final version of a Stellite 1919A6 barrel produced by SAK (Saco-Lowell Shops,
Saco-Lowell was an old line New England manufacturer
of machinery for the textile industry before receiving an Ordnance contract to
produce M37 BMGs and parts.
later acquired by Maremont, the muffler people, renamed Saco
Defense Systems and produced the M60 machine gun.
Saco produced not only Stellite A4/M37 and A6
barrels but also complete purpose built M1919A6 and M37 BMG’s all of which
left the factory with Stellite barrels.RIA also produced purpose built M37’s and Stellite
barrels for both the A4/M37 and the A6.
The M37, the replacement for the M1919A4 Fixed,
M1919A4E and the 1919A5, was the last of the Cal.30 air cooled BMG’s.
Thisparticular barrel has no ordnance flaming bomb
markings. likely because Ordnance stopped using this symbol in favor of an eagle
in a rectangle over three stars as a marking on complete weapons after the
Department of Defense succeeded the War Department.
It does have the final
proof "P" on the extreme right of the photo and the chrome plated bore ahead of
the liner and chrome plated front bearing surface.
courtesy ofTom Pfremmer
This barrel marking is on anRIA A6 barrel, the significance of-G following the part number is unknown.
It may be a production code assigned by RIA to
identify which production line produced it, or since the Stellite liners were a
shrink fit to the tube, this code may identify the size of
the counter bore in the tube so it could be matched up with
the right size liner.
This is the same A6 barrel with the paint stencil
Drawing (D) 7162295 dated September 12, 1945 shows the parts of a first type
Stellite barrel assembly for the M1919A6.September 12, 1945 is 10 days after the Japanese
signed the surrender documents aboard the USS Missouri in Tokyo Bay.
The Stellite “liner” was held in place by the
“retainer” actually a steel chamber insert which was screwed into the “tube” and
locked in place by the pin driven in from the rear.
Notes on this drawing require stenciling this
assembly “D7162295 LINED ASSY.” in ½ inch high letters with heat resistant white
paint, a practice that was continued on the later 718400 A6 and 7184399 A4 Barrel
assemblies that had chrome plated bores ahead of the liner and chrome plated
front barrel bearings after June of 1953.
The reason for the
change of drawing numbers for the barrel assemblies and the
individual parts seems to be more associated with Ordnance
changing the dimensions of letter sizes of the drawing media
to agree with ANSI standard civilian drawing sizes than any
actual change in the design of the barrel assemblies.
Drawing C 7162479 dated September 12, 1945 shows the Stellite liner which is
5.250 inches in length.Apparently there were 5 different outside diameters
for this part starting with .5010 and increasing in diameter by .0005 increments
to a maximum diameter of .5030.Notes indicate “USE SELECTIVE ASSEMBLY TO OBTAIN
SHRINK FIT SHOWN ON DRG. D7162295” which is the previous drawing of the barrel
assembly.There is also a note explaining that “RIFLING MAY BE DONE
AFTER ASSEMBLY’and adetail drawing of the standard 4 groove, 1 turn in
10 inches, right hand twist .30 caliber rifling.
Note the shoulder on the
Stellite casting .750 inches from the chamber end which butted against a
matching cut in the bore of the barrel preventing the liner from moving during
of Chris Ott
This photo shows
a 1962 Saco A6 Stellite barrel complete with original packaging.
cardboard tube with sleeve end, original VCI wrapping paper and a VCI wick for
the bore.VCI is the acronym for volatile corrosion inhibiter a
chemical compound that gives off vapors that protect against rust or corrosion.
who has purchased a Smith & Wesson firearm in the ‘70s has seen the piece of
brown paper with the blue S&W logos placed in the box this is VCI paper.
manufacturers of reloading dies also include a small piece of VCI paper in the
die box .
Previous to the adoption of VCI packaging, barrels were filled and coated with
Cosmoline and wrapped in Kraft paper.Various other packaging schemes were used over the
years, including a lightweight cardboard tube over wrap with the ends stapled
developed a wooden crate for quantity shipment of replacement barrels.
courtesy of Chris Ott.
up of the label on the shipping container pictured above.The 9/62 date indicates that that there was still an
need for A6 parts into the 60’s.
of Rollin Lofdahl
is a D35233-14 double marked with the Saginaw (SG) andGuide Lamp (GL) imprints.
located in Anderson, IN was a Division of General Motors Corporation.
Instead of changing the name of a company that GM acquired, like Saginaw
Steering Gear or AC Spark Plug,GM corporate policy was that they just added
“Division Of General Motors” after the original name.
Barrels markings indicate that some barrels were manufactured by Guide Lamp
under sub-contract from Saginaw and some were produced under direct contract.
Guide Lamp is also famous as the manufacturer of the
Cal.45 “Liberator” single shot throw awaypistol made from sheet metal stampings, and the sole
WWII manufacturer of the M3 and M3A1 “Grease Gun” submachine gun.
The Anderson, IN plant was last operated as a Delphi
Automotive production facility.
courtesy of Rollin Lofdahl
This D35233 RIA
produced barrel has the number 44 stamped on the muzzle end.
significance of the marking is unknown, it is possible that this number
indicates the year of manufacture, 1944, butthe D35233 barreldesign was superseded by D35233-6barrels on 10-03-1940 and it is not likely that RIA,
who was the “in charge” ordnance facility for M1919 production, would be
producing designs superseded 4 years earlier.
Information from the
Rock Island Arsenal Museum regarding the
Manufacturing History and Manufacturing Plant History of RIA that
has recently came to light gives us a better picture of post
WWII barrel production.
At the end of WWII
production contracts with arms contractors such as Saginaw
Steering Gear were canceled.
cancelation also ended the supply of barrels furnished by
the contractors which was not
perceived a a big problem since we were not at war and we
had, literally, tons of barrels on hand.
In FY (Fiscal Year)
1950 the Rock Island Arsenal began to tool up for barrel
production by enlarging their chrome plating operation for
Caliber .50 barrels and and revamping their barrel
production facilities for .30 Caliber barrels.
By 30 June 1950 they
had manufactured 675 D7162295 M1919A6 barrels. These
are the original Stellite insert A6 barrel assemblies
lacking the chrome plated bore and front barrel bearing.
Because of the start
of the Korean War on 25 June 1950, production of barrels,
overhaul of small arms, production of parts for the M1919's
and general activity of all kinds ticked up at RIA.
In FY 1951 they
produced 8490 "Barrel, assembly Cal. .30".
It is not known if
these were all A6 barrels or a mixture of A4 and A6 as the
report did not include the drawing number or any other
identifying information. Stellite barrels are always
referred to as assemblies so whatever they were, they had
In FY 1952 which
ended on 30 June 1952 RIA was producing "Cal..30 machine gun
liners" (the Stellite liners) now with new assembly drawing numbers 7148399 for
the A4 and 7148400 for the A6, and produced 17,600 .30
caliber barrel assemblies.
Both of these
drawings have the original date of 1-11-52 and a note that
superseded the previous Stellite lined barrel drawings
In FY 1953 which
ended on 30 June 1953 RIA produced 88,500 "M1919A4 barrel
The Korean War
Armistice on 27 July 1953 didn't end production of barrels
and other M1919 parts.
FY 1954 saw RIA
producing 57,000 .30 caliber barrel assemblies, again we
don't know which types as there are no references in the
report these barrels likely had the chrome plating on the
front barrel bearing surface and the chromed bore adopted
for both A4 and A6 barrels in June 1953.
During this 5 year
span besides production of new barrels RIA was "overhauling"
barrels to the tune of about 25,000 units and
producing new D35388 M1917A1 barrels.
It is not known if
this "overhauling" of barrels was merely some sort of
reconditioning process or barrels were being converted to
Stellite lined versions.
During this 5 year
period of production of barrels, building of new M1919A6
weapons, reconditioning M1919A4, M1917A1, M1 rifles,
various types of M1903 rifles and
M1918A2 BAR's RIA consumed 8.6 million rounds of Cal.30 M2
Ball ammunition and 262,000 rounds of Cal.30 H.P.T. (high
pressure test) ammunition for function testing and proofing
M1919’s being air cooled weapons consumed barrels at a prodigious rate.Each machine gun squad was required to have at least
one spare barrel, carried in a canvas bag along with other repair parts, such as
a complete bolt assembly and a barrel extension while in the field.
canvas bag for the barrel is officially known as Cover, spare barrel,M9its drawing number is D30674.
The earliest versions was made of “ol-db”
(olive drab) cotton duck with a "lift the dot" closure and the flap
and about 10 inches of the body was lined with latigo leather.
The lower portion was lined with asbestos cloth.
Picture courtesy of Matt Ager
This is a view down the inside of the leather and asbestos
lined cover. It appears that his rather elaborate
design was dropped early in WWII.
Apparently, the asbestos barrel changing gloves and
the asbestos lined spare barrel cover were not considered health hazards at the
time.Later versions of the barrel cover dispensed with the
This picture shows the M9 spare barrel cover, an unlined WW II style, and
an A4 barrel with barrel extension attached. The cover will accept the
barrel and barrel extension assembled and also has room left over for a
spare bolt in the canvas bolt pouch.
This is likely how the barrel was carried in the field, that is assembled
to the barrel extension, as this method of carry would shorten barrel changing time.
A-6 dated May 28, 1941 is the earliest SNL for the M1919A4 that we have
encountered, although it states that there was at least one earlier version,
dated December 1, 1939,published.
The 1941 SNL is entitled “Parts and Equipment” and
is one size fits all document that lists not only repair parts and assemblies
for the M1919A2, M1919A4 Fixed and Flexible and the M2 Tripod but such oddities
as the Machine Gun Hanger M3 and the Ammunition Hanger M8 .These two items are for pack transporting the
weapon, accessories, and ammunition on horses.
SNL states that during twelve months in a theatre of operations 400 barrels are
required for the maintenance of 100 M1919A4’s.Additionally it lists the required spare parts,
accessories, ammunition boxes, cleaning equipment, ammunition belts, canvas
goods, belt filling machines, special purpose tools along with the weight of the
required items for “Combat Vehicleand Train Defense Units (Horse or Mechanized)”.
this was 1941 the Army still had a few horses, but the “Train Defense Unit” is a
new one on me.Must be something left over from WWI.
my Uncles, Charles Fassola, entered the Army in 1939.Chuck, a steamfitter in civilian life, was assigned
to a Ft. Reilly, KS Cavalry outfit that was still horse mounted. At one time I
remember seeing a picture of him, mounted on a horse, complete with Patton
saber, rifle in a scabbard, riding pants with suspenders, boots, spurs and a campaign
He looked like something out of the movie “The Wild Bunch”wish Ihad the picture.
Starting with SNL A-6 published in 1943 the plethora of information contained in
the 1941 SNL A-6 was divided into three separate booklets, List of All Parts,
Organizational Spare Parts, and the Addendum which listed major items,
maintenance parts and equipment available.This last publication was intended for use by
Ordnance personnel only.
1944 these booklets were assigned publication number prefixes which identified
the nature of and the intended audience for the contents.ORD 9 SNL A-6 replaced the list of all parts, ORD 7
SNL A-6 replaced the organizational maintenance allowance, and ORD 8 SNL A-6
became the field and depot maintenance allowances references. This method of
identifying publications continued into the early 1960’s when a new series of
Technical Manuals combined everything back into one reference source.
TM9-1005-212-25,dated 28 May, 1969, replaced all of the publications
listed above and then some.This Technical Manual covered the M1919A4,M1919A6, and the last of the breed the M37 along
with the M2 tripod.
this late date, the A4 and A6 being in semi-retirement in some Army Reserve and
National Guardunits having been replaced by the M60 GP machine gun
starting in 1957, only Stellite lined barrel assemblies were available.This document calls for a 15 day maintenance
allowance of 2 barrels per 100 weapons and a one year contingency allowance of
36 per 100 weapons.
There you have
it, my take on barrels and a few other things.
sincere hope it that you found this article both useful and entertaining.
CREDITS AND ACKNOWLEDGEMENTS
Arsenal Museum, Jodie Creen Wesemann,
who supplied all of
the Ordnance drawings, and Ordnance Publications quoted.Without Jo’s generous help and unfailing patience,
we would still be guessing about happened and when it happened.
Lofdahl, a good friend, and knowledgeable guy who has been much help in
deciphering all of this.Rollin is my Technical Editor, which means he
provides information, encouragement and most important, the very necessary
sanity checks on what I commit to paper.
special thanks to the members of the 1919a4.com forum, and the forum founder
“Shots” who help with pictures, encouragement and really odd finds.They are the eyes and ears of this effort.
individually credited, those lacking a credit are the authors.
History of the Browning Machine Guns, Frank Iannamico,
Machine Gun Vol. 1, Dolf L. Goldsmith,
World War I,
Weapons of WWII, Bruce N. Canfield,
of Military Firearms, Phillip Peterson, Editor,