The development and issue of the M1919A6 Caliber .30 Browninglight machine gun always reminds me of the old saying that a camel is a
horse designed by committee.
It
looks like the small arms equivalent of a couple of kids building a dog house
from scrap lumber.
The A6 was fathered by necessity and birthed by expediency.
In early 1942 the U.S. Army Infantry Board began to think in terms of a
weapon to replace the M1918A2 Browning Automatic Rifle as the squad base of
fire.
The BAR was accurate,
reliable and generally well liked by the troops, however it had a few drawbacks.
It was expensive,difficult to manufacture, unable to provide sustained covering fire
because of the limited magazine capacity of 20 rounds and overheating.
The M1918A2 was the result of an “improvement” process applied to the
M1918 version.
The improvements
consisted of a barrel mounted bipod, redesigned flash hider, modifications to
the trigger housing to provide guides for magazine insertion, a rear sighting
system providing windage adjustment and removal of the selective fire option
replacing it with two rates of full auto fire.
Later in 1944 a barrel mounted carry handle was also developed along with
a change to the design of the bipod legs.
The Infantry Board wanted a relatively light weight weapon that was rifle caliber and
belt fed capable of some level of sustained fire and able to be deployed by one
man.
The Infantry automatic weapon work horse was the M1919A4 .30 caliber air cooled
Browning mounted on the M2 tripod. Weapons
Platoons were also equipped with M1917A1 water cooled Brownings.
The M1917A1 had almost unlimited sustained fire capabilities provided you
had an adequate ammunition and water supply but the M1917A1 mounted on it’s like
designated tripod weighed in at nearly 100 lbs.
If deployed at all it was relegated to static/defensive positions.
The M1919A4 needed two men to deploy, the Gunner carrying the tripod and the
Assistant Gunner carrying the A4.
The tripod/A4 combination weighed in at 48 lbs and usually was separated into
two pieces to change the weapon’s position.
The Infantry Board was familiar with the German MG 34 and MG 42 weapons which featured a
butt stock and a bipod mounted on the weapon, they could also be mounted on a
tripod if the need arose.
This appeared to be the style of weapon best suited to the perceived task.
Ordnance wanted to purpose build a weapon to serve the Infantry’s needs.However the system in use at the time to solicit designs, develop new
weapons then test, field trial, and mass produce took years.
The Infantry Board, well aware of the time required to approve new weapons, needed
something to satisfy their needs yesterday not years down the road.
In hindsight the Board hit the nail on the head regarding the long lead time to production
of a new weapon.
The M1919A4/A6 was
replaced by the M60 GP machine gun in 1957.
Much wrangling back and forth ensued with the Infantry suggesting that the
M1919A4 currently in production could be modified at little cost using non
critical materials to satisfy their immediate needs and some new weapon could be
developed at a later date.
By early 1943 Ordnance agreed to develop a kit of accessories to be furnished to
adopt the M1919A4 to the configuration that the Infantry desired.
Duringdevelopment and testing of
the new accessory kit Ordnance discovered that this was not going to be a stroll
in the park and decided to purpose build and name the modified weapon M1919A6
and declare it a Substitute Standard, Major Item number 51-125.
One of the design shortfalls of the M1919A4 was the fact that the barrel had to
be changed from the rear and required removing the back plate, bolt, lock frame,
barrel and barrel extension in short you had to field strip the weapon.
The German MG 34 and MG 42 had a much simpler and faster method of barrel change
where the receiver pivoted to expose the chamber end of the barrel.
Ordnance had been experimenting with modifications to the A4 to provide a
quicker method of barrel change.
These experiments were based on various designs for changing the barrel
from the front including a barrel support similar to the Caliber .50 Brownings.
The
A6 development looked like a good time to try for a different
style front changeable barrel.
Here’s a picture of an early experiment with a front change barrel assembly that
looks remarkably like the Caliber 50 air cooled Brownings.
One of the problems that surfaced with the development of the air cooled M1919
Tank Gun the parent of the M1919A4, which were based the M1917 water cooled
design was the
need for a heavier barrel to dissipate the heat generated by the lack of water
cooling.
The Tank Guns had 18 inch barrels that weighed about 5.5 lbs versus the M1917 barrels weight of 3 lbs.
The
M1917 was a purely recoil operated weapon.
Since the recoil energy of the cartridge remained the same and the weight
of the recoiling parts increased additional energy to provide reliable operation
of the weapon had to come from somewhere.
John Browning solved the immediate problem by placing a “muzzle
attachment” at the front of barrel jacket that also served as a front barrel
support
bearing and a “muzzle attachment plug” containing a .872 hole.
Later this arrangement became known as a “booster”
During the very short time that the
projectile entered the booster chamber and exited through a much smaller orifice
expanding gas pressure resulting from the burning of the propellant exerted
force on the front of the barrel providing additional rearward thrust or “boost”
which compensated for the heavier recoiling parts.
Technically speaking the M1919’s are recoil operated/gas assisted
When the M1919A4 was developed, it was decided to increase the barrel length to
24 inches to provide higher muzzle velocity and increased range.
The change to the 24 inch barrel increased the weight of the barrel to
7.5 lbs and required changes in the “booster” system, basically making the
orifice smaller which added additional rearward thrust.
Apparently during the initial design of the A6 the subject of front changing
barrels resurfaced and someone came up with the idea that the boost feature could
be eliminated by decreasing the weight of the recoiling parts.
Eliminating the
booster and shortening the barrel jacket so the end of the barrel would be
accessible would allow the barrel to be removed from the front and replaced.
The only practical way to do this was to make the barrel lighter so a
barrel with a slimmer profile and wrench flats on the end was designed.
This page from TM 9-206, courtesy of the 90th Infantry Division Association, printed in September,1943 just about the time M1919A6 made
its battlefield debut, explains how to change the barrel from the front.
While no mention of the M6 combination wrench is made, the opening with the
rounded ends that is used to turn the booster plug and booster bearing wrench
also fits the A6 barrel's wrench flats.
The
operators of the weapon still had the option of changing the barrel from the
rear if they wished.
Conventional
wisdom has always held that the reason for lighter A6 barrel was to reduce the
overall weight of the weapon which it did.
However, the real reason for a lighter barrel was that it would reduce the
weight of the recoiling parts, the reason for having a gas assist booster in the
first place.
The shortened barrel jacket and lack of a booster plug on the A6
resulted in the muzzle with the wrench flats protruding from the end of the
front barrel bearing.
Since the
front barrel bearing was bored straight through at 1.254 the barrel of the A6
could be changed from the front with or without the use of M6 combination
wrench.
Some
writers believe that the protruding wrench flats on the barrel were an attempt
to make it easier to set the head space, however, there were already methods to
adjust head space that required only the use of a cartridge.
The first M1919A6’s were committed to combat in the Italian Campaign around
Salerno in the fall of 1943 and later at Anzio in January 1944. These A6’s had
the original front barrel bearing having no gas assist booster.
The decision to reduce the barrel mass to have a front changeable barrel was
probably not a good one.The
M1919A4 with its 7.5 lb barrel was already marginal on overheating during
sustained fire.Reducing the
barrel mass did not make this situation any better
The Saginaw Steering Gear Division of General Motors, the premier quality, low
cost and high production manufacturer and, after July, 1943 the only producer of
the M1919A4, was selected to be the producer/developer of the new weapon.
Saginaw got busy and fabricated some new
parts cast using an alloy developed by Saginaw Malleable Iron, one of their
subsidiary companies.This alloy, a
perlitic malleable iron, called ArmaSteel, had been developed pre-war to cast
certain automotive parts that were difficult to machine.
Saginaw had already used ArmaSteel to fabricate some M1919A4 parts with great
success.
The new M1919A6 parts were a one piece front barrel bearing having no booster
feature and the head section of the bipod which slipped over the bearing and was
retained by a snap ring.
The bipod
head was designed to mount the same adjustable legs used on the M1918A2 BAR.
The new front barrel bearing had to be longer than the original to
accommodate the bipod head resulting in the need for a shorter barrel jacket.
A sheet metal butt stock and a rather flimsy sheet metal and plastic carry
handle that slipped over the barrel jacket was also standardized.
A review of the Ordnance Department drawings of A6 specific parts shows a common
original date on the drawings of 7-23-43.
I take this to be a convenient earliest date to cite for beginning of
production.
This cut from SNL (Standard Nomenclature List) A-6 dated September 1943 is the
first SNL illustration of a production M1919A6.
The adjustable BAR legs are supplemented by two small fixed rests just
below the leg attachment to the bipod head for use when the legs were folded in
the up position.The early style
carry handle is free to slide up and down the jacket and often did at the most
inopportune times.
The length
adjustment thumb screws for the legs are located at the bottom of the fixed leg just above the feet of the sliding leg
when at the shortest position.
This adjustment feature would be changed
in 1944 along with a new carry handle similar to the M1918A2 BAR carry handle
introduced in
1945.
Other than the added parts the weapon remains a M1919A4.And just like the A4, with the addition of a pintle the A6 could be
mounted on any tripod that would accept the A4.
M1
metal links on the left, fabric 250 round belt on the right. The
cartridges with the red tips are the tracer rounds.
Like
all the other M1919’s the A6 could use either ammunition supplied in fabric
belts or metallic link belts.
Typically during WWII infantry machine gun ammunition was furnished in
“Functional Lot” form; for machine guns the cartridges were belted or linked in 250 round
units and packed in an expendable metal container, the M1 ammunition box shown
above, four containers in a wire bound wooden crate, ready for use.
Commonly, Infantry units used the ratio of 4 Ball to 1 tracer.
In order to conserve steel for strategic
uses fabric belts were used almost exclusively for ground units.
My wife’s Uncle a member of the 69th Armored Field Artillery
Battalion stated they would occasionally receive linked ammo after the invasion
of Southern France in August, 1944.
This cut also from the September 1943 SNL shows barrel group parts from both the
A6, the upper part of the illustration, and the A4 and A5 in the lower.
While the barrels are the same length 24 inches the C93962 jacket for the
A6 is 16.5 inches long vs. the A4 jacket at 19 inches in length.The length difference is made up by the longer front barrel bearing
required to mount the A6’s bipod head.
Another cut from TM 9-206 showing details of the early A6 specific parts
including an unusual looking top cover latch which we have not seen before.
This view clearly shows the lack of a booster and the protruding muzzle with the
wrench flats.
Even when it was discovered after the Italian deployment
that the A6 required a gas assist
booster to operate reliably and the cap style booster and a newly designed front
barrel bearing were adopted,
by simply removing the booster cap the operator would have access to the flats
on the end of the muzzle preserving the front barrel changing capability.
Author's photo courtesy of the RIA Museum.
While some A6’s were purpose built and can be identified by the designation
M1919A6 stamped on the right side plate of the casing, some weapons were rebuilt
into the A6 configuration from other models such as the M1919A4 Fixed weapon
used on early tanks and the M1919A5 designed primarily for the M3A1 Stuart light
tank.These rebuilt weapons can be
identified by over strikes on the side plate model designations.
The photo of the A6 above shows that it has
lived several lives.
Originally built by RIA as a M1919A4 in
about September of 1941 it was converted by RIA to M1919A5 (Note the 4 holes
for the retracting bar guides and the first model designation overstrike)
configuration also note the faint "FK" (Frank Krack) to the right of
the "U.S. INSP".
The weapon was not remarked on conversion to
M1919A5 because it was done at the same facility with the same Chief of
Small Arms Inspection as
already marked and Ordnance directives did not require remarking under these
conditions.
However, this weapon was remarked near the top of the right side plate on
conversion to M1919A6 with the RIA and "EB" (Elmer Bjerke) who succeeded
Krack on January 6, 1947. Mr.
Bjerke remained the RIA Chief of Small Arms Inspection until his job was eliminated
in 1958.
According to Goldsmith Volume 1, 330 M1919A5's were converted to M1919A6's
between 1955 and 1957. The weapon pictured may be one of the weapons
referred to.
All of the purpose built A6’s in the WWII era were produced by Saginaw
Steering Gear in their Saginaw, MI plant.
Rock Island Arsenal may have done some A6 conversion work to meet demands
for these weapons during WWII.
This cut is from ORD 9 SNL A-6 dated April 1947 and shows the cap style booster
and its companion front barrel bearing along with the early style clip to lock the cap to the
bearing.This style appeared
sometime in the summer of 1944 apparently as a result of problems encountered in
combat use during the Italian campaigns of 1943 and early 1944.
This arrangement required yet another and even shorter barrel jacket C7160455
which has an overall length of 15.9 inches.
Apparently the early A6, recoil only model lacking the gas assisted booster did
not apply enough recoil force to the barrel for reliable operation.
In addition the snap ring bipod
retainer on the original design was only .048 inches thick and sometimes broke
allowing the bipod to slide off the front of the weapon.
The last style bipod retaining snap ring thickness was increased to .094 inches.
The removable booster cap allowed easier cleaning than the one or two piece
A4 boosters.
This cut also from the 1947 ORD 9 SNL A6 shows the late/post WWII
configuration.
This illustration shows the “new” style adjustable legs adopted in July of 1944.This style consisted of the same leg parts as the old but assembled them
differently.The length
adjusting thumb screw is located just below the thumb screw used to hold the
legs in the folded or extended position.
The early style had the length adjusting thumb screw just above the foot
where it was difficult to grasp and became jammed with mud.This leg change also affected the M1918A2 BAR.
Also shown is the cap style booster and the early "U" shaped version of the
clip that locked the cap to the bearing. Later this clip was modified with
a hinged arm to lock the clip in place.
Also present was a new style carry
handle that appeared in April of 1945 that clamped to the barrel jacket and
didn’t flop around like the cheesy original.This handle is similar to the design of the BAR carry handle.
One problem that affected U.S. troops in the European Theater in WWII was the
excessive, as measured by German standards, flash signature of our weapons.
Efforts began as early as 1943 to develop some sort of flash hider for the
Browning .30 calibers many were tried, but only one design showed both promise
and adaptability.This style used a
simple cone with an included angle of about 15 degrees.
The M6 flash hider replaced the
booster/bearing on the M1919A4, the M7 replaced the booster cap on the
M1919A6 and the M8 and a modified muzzle gland was developed for the M1917A1
water cooled machine gun.While
these were developed late in WWII, very few, if any, ever made it to the field.
This cut is from MWO ORD A6-W12 (Maintenance Work Order for Group A-6 weapons)
dated July 1949.
A-6 Group weapons include all of the M1919 family of air cooled caliber .30
Brownings.
The purpose of this work order was to replace all of the cap style muzzle
boosters and bearings on M1919A6 weapons with the .048 inch bipod retaining
rings and the early style M7 flash hiders with the newly dimensioned booster
chamber M7 flash hider.
This MWO only affected weapons in the field or weapons being reconditioned, not
weapons in storage.
This would explain why few Korean War photos of A4’s or A6’s show flash hiders.
When the Korean War started Ordnance apparently issued weapons directly from
storage without modifying them.
Apparently there will still issues with insufficient gas assist force because
the latest design M7 flash hider for the M1919A6 has a larger
booster chamber.
Only about 44,000 M1919A6’s were produced during WWII.
Photo courtesy of the RIA Museum.
This is the final post Korean War version complete with M7 flash hider.
Note the left side view showing the rear sight base having only two
attaching rivets and no milled cut or tapped holes for an optical sight base.
The left side plate shows the unused third rear sight base mounting hole.
The flash hider is equipped with the last style mounting clip with the
swinging arm.
The right side plate shows the four holes for the retracting bar
guides required on the M1919A5.
The M1919A6 remained in active U.S. service through the introduction of the M60GP machine gun in 1957.
Some units
were still using the M1919A6 into the early stages of the Vietnam War and Army
National Guard and Reserve units had them in their arms rooms into the mid
1960s.
In 1949 the Rock Island Arsenal began to produce A6 components
for rebuilding of existing A6's and the conversion of M1919A4's to A6's.
These components included M7 flash hiders, front barrel bearings, carry
handle assemblies, shoulder stocks, bipod heads and barrels.
In 1953 RIA began planning for the resumption of Caliber .30 Browning
machine gun production this was likely to replace battle losses in the
Korean War.
RIA hadn't produced a new .30 Caliber Browning Machine gun since 1944.
The History of the Manufacturing Plant of the Rock Island Arsenal 1 July
1953-30 June 1954 indicates that 7,200 new M1919A6's were produced along
with rebuilding 587 A6's.
The RIA Historical Summary for the period of 1 July through 31 December
1955 lists the manufacture of 3 M1919A6's. These are likely the last
RIA purpose built A6's.
The Historical Summary for the period 1 July through 31 December
1957 lists 432 M1919A6 rebuilt from M1919A4 Flexible models.
This is the last mention found so far of RIA's involvement with the
M1919A6.
On 12 July 1957 RIA transferred responsibility for small arms
production and engineering support to the Springfield Armory now the site of
the Springfield Armory National Historic Site.
In addition to the Rock Island Arsenal's post Korean War A6 production
Saco-Lowell Shops, Biddleford, ME, best known for building M37's, also
produced purpose built M1919A6's, however, records concerning their
production are sparse.
Lake City Ammunition Plant was still loading Caliber .30 Ammunition as late as 1976.
As the M1919A4 and M1919A6 were being phased out of U.S. service a good number of them were transferred to
the Israeli Defense Forces as military assistance items.
The IDF made a few modifications necessary to convert them to caliber 7.62X51
NATO and designed a new bipod as part of a kit containing a carry handle and
sheet metal stock that could convert any M1919A4 into a sort-of A6.
The IDF reverted to the "Kit" concept and used standard profile A4 barrels
and converted some M1919A4's into a sort of A6 using either the M6 flash
hider or a conventional booster/bearing.
What
they sacrificed in increased weight and loss of the front change barrel option they gained back in improvement in barrel
heat dissipation and tactical flexibility.
The IDF produced sheet metal butt stock which is an exact copy
of the USGI design however it is marked with Hebrew characters on the right side
upper rear of the stock.
The M1919A4 and the A6 wannabes soldiered on with the Israeli’s for quite some time.
The IDF was still contracting fabric belt production in the Netherlands
in 1976.
The IDF favored a 225 or 230 round
fabric belt because it would fit more conveniently in the post Korean War M19A1
ammunition box which would also hold 250 rounds of linked 7.62X51 or U.S. caliber .30 ammunition.
Author’s photo
The IDF designed and produced bipod offers a few improvements to the original
design.
While it has fixed length legs the bipod is locked to the barrel jacket holes
with a spring loaded pin, the knurled knob in the picture, and can be positioned anywhere on the barrel.In addition the attachment to the jacket allows the operator to traverse
about 20 degrees and to cant the weapon without picking up the bipod and
repositioning it or skidding the feet.
Purists turn up their noses at the IDF bipod because it’s not USGI but, even
though it’s a little heavier, it is more practical design for the operator.
Author’s photo
With the legs folded you can see the solid steel block that takes the place of
the two sheet metal rests on the USGI bipod.
Most of the “parts kits” available on today’s market for conversion to
semi-automatic versions of M1919A4/A6’s are Israeli vets and marked with IDF
property marks.
The M1919A6 like most compromises left everybody a winner, or looser, depending
on your point of view.
The infantry got a weapon sooner rather than much later, and Ordnance got to
develop the M60GP machine gun.
Funny thing about the M60, there’s no middle ground; the users either loved it or
hated it.
Credits:
All Ordnance publications pictured or quoted:
Rock Island Arsenal Museum, Jodie Creen Wesemann
Infantry Weapons Of WWII, Bruce Canfield, Andrew Mowbray publishers
The Browning Machine Gun Volume 1, Dolf Goldsmith,
2-6-11
