Hi guys, thanks for tuning in to another
video on ForgottenWeapons.com. I'm Ian McCollum, if you can see me behind this forest of Bren guns. What we are looking at today are the World War Two wartime simplifications of the Bren gun. Now I mentioned in our previous
video on the original Mark I Bren here, that the British had produced about
30,000 Bren guns as of May of 1940, when the Dunkirk evacuations happened. This of course is the evacuation of the British
Expeditionary Force from mainland France, and it's really kind of one of the darkest
parts of World War Two for the British. Now in the aftermath of this
evacuation they go through and realise they have less than 2,300
Bren guns left in the country out of 30,000 or so that they had going in. And this sparks a bit of a panic like, "What happens if like the Germans manage to
disrupt production of more new Bren guns? We're going to be really screwed." This is a very important tactical
weapon for the infantry company. So in September of 1940 they
formally adopt two separate solutions. And what had happened
is they looked at first off, "How can we speed up Bren gun
production without interrupting it? Like, what can we implement right
now that'll make a Bren gun [faster], but require basically no
setup or infrastructure?" And so that becomes known
as the Mark I Modified Bren. And it is in effect removal of some
lightening cuts and special features, most significantly, most noticeably, the extra
dovetail bracket on the side of the receiver. But they keep some of the complex
stuff like this funky-looking Mark I barrel. And frankly that only manages
to increase production by like 5%. However it's something they can do without
interrupting the continuing supply of new guns. At the same time they also look at, "OK, if we start over, what can we do to
simplify the gun that would involve retooling?" And that program becomes the Mark II Bren,
which is substantially modified in a lot of ways. In fact almost every part on the outside of
the gun comes out differently on the Mark II. They leave the internals the same, so the
bolt, the bolt components, the operating rod, bolt carrier, those parts will interchange
between all of these different models. But everything else: the receiver is different,
the sights are different, the barrel is different. And the Mark II Bren kind of
takes over into production. So let's go ahead and take a closer look, and I'll walk you through the
differences between all three of these. I think the way we're going to do this is we're
going to put all three guns together side by side, and we're going to start at the
back and work our way forward. So throughout the course of this we
have our original Mark I here in the back, we have the Mark I Modified here in the
middle, and we have the Mark II in the front. Important to point out the Mark I Modified, that "Modified" was never adopted
as an actual formal designation. These simply continued to be
marked and referred to as the Mark I. So on the Mark I Modified guns, again, this is ... changes we can make
without interrupting current production. So easy enough to get rid of this
shoulder stop pad, that goes away. And they stop equipping them with the bottom
handles (which I don't have installed here), but there was originally a wooden handle
for controlling the back end of the gun. That's superfluous, you really
don't need that, so that goes away. For the Mark II, if we're going
to change this up entirely, you can simplify the design
of the buttstock quite a lot. You can get rid of this hump. The fancy
cupped spring-loaded butt plate goes away in favour of just a simple flat butt plate. It still has a sling attached to this side,
which we'll take a look at in a moment. Now the sights and receiver. On
the modified guns it's easy enough to get rid of this extra dovetail bracket,
that's kind of an obvious thing. I have a separate video on the sight that
went in here, it was really superfluous. There was also a lightening cut up here
at the front of the receiver originally. That goes away, that's superfluous as well. And you can see that the lines
are substantially simplified here by getting rid of some of those features. Once again though, ... if we go to
a whole new design of receiver, a lot of this can be made simpler. So you can see the complex steps
here in the back of the receiver, if you just make the whole thing a little
bit taller you can have more straight lines. And that's faster and easier to machine. The [original] drum sight on
these guns ... was pretty complex, like there's a lot of little spring-loaded
bits and cams inside there. And to what end? Do we really need that?
This is an outgrowth of the ZB 26. Well, instead they decide to adopt a much more
typical sort of micrometer ladder rear sight. So you ... now don't need the
first dovetail on the receiver either, so you can make the whole thing flat sided. And this is a much quicker
and simpler sight to make. So this is the most easily distinguishable
visual feature of the Mark II Bren, this ladder sight in place
of the early dial sight. Moving up towards the front of the gun,
there are some rather complex flutes up here on the front of the original Mark I. They simplify that substantially
here on the Mark I Modified. And they keep that ... simplified pattern up here. Really kind of unchanged between
the improved Mark I and the Mark II. We can also see some simplification
on this sort of gas shield right here. It goes from being nicely contoured to
being just flat on the Modified Mark I, and then it simplified even
further on the Mark II guns. Now the other really visually
distinguishable difference between the Mark I and
the Mark II is the barrel. So the Mark I had this stainless steel
flash-hider extension on the front. It was done for good sounding reasons,
but ultimately it was not necessary. And so with this development program they
... produced a whole new pattern of barrel, this was the Mark II barrel. It gets rid
of the stainless steel element entirely. [A form of] stainless steel continues to
be used ... for the gas block right here, ... where it's particularly important
to have corrosion resistance. But the flash hider is
built right into the barrel, the front sight is revised slightly, it's made a little bigger and beefier,
and it's moved forward a bit. And this is a much cheaper,
simpler barrel to make. In addition, you can see the sleeve
for the carry handle is simplified. Where this was originally a single milled
piece with a bunch of fancy lightening holes, it's now basically solid with the
carry handle itself welded on. Overall, the Mark II Bren would be like a
third of a pound heavier than the Mark I, because most of these simplifications
involved not doing extra steps to lighten things. Just to put this in perspective, the
original early Mark I pattern Bren guns had something like 2,200
machine operations, and over 1,000 hand fitting operations involved
in the production of every individual gun. So there was a lot to work
with to simplify these. One additional change that unfortunately I
don't have here to show you, was to the bipod. There was a substantially
simplified Mark II bipod that got rid of the spring
connection between the legs and each leg just independently folded. And of course they got rid of
the extendable functionality. I don't have a Mark II.
However, in addition to the Mark I they also just did a simplified
version of the Mark I bipod, which we do have over here on our Mark II gun. Where the upper assembly here is the same
(right there, that's all the same), but the legs no longer extend. And so that's a bit of
simplification that was easy to do. In general, a lot of these parts were kind of treated independently
and individually by British production. Their emphasis was on getting
guns into the hands of soldiers, not making sure that every gun scrupulously
fit a particular set of part designations. So things like the different
bipods on the different models, different use of the
different pattern barrels. You will see some of that
interchangeability in the field. One other thing that was addressed in the
simplification program was, to be honest, reliability. The Bren gun had performed
extremely well in trials. However, that was done with sort of a basic
standardised cleaning and maintenance system that it turned out wasn't
really possible to maintain on the battlefields in the early
months of World War Two. And British gunners found
that without regular cleaning, the guns tend to build up
large amounts of carbon. Which eventually would actually restrict
and then stop operation of the gas piston, causing the guns to ...
basically to stop working and to become very difficult to
clean and get back into service. Now part of the problem was this series of
gas vents that are directly under the bipod. So the bipod fits onto this spigot. And having these gas vents, carbon
tended to build up on the bipod. And what you had to do was swivel
the gun back and forth on the bipod to break up the carbon sticking
between this and the bipod sleeve. The problem is over time
that would erode the fit between ... this cylinder and
the inside of the bipod sleeve. And ... once that was no longer a
tight fit, gas could escape there, and it kind of sped up the problems. Less gas pushing the piston back, and
more of it leaking out around the bipod. So one of the improvements made at
this point was a Mark II gas cylinder here that was solid, got rid of these holes.
So it didn't solve all the problems, at the same time they also enlarged the gas
ports to give the guns a little more energy. As a result of that, the guns tended to be
cycling harder, and so the Mark II also has a double nested set of recoil springs in
the buttstock instead of a single spring in order to absorb the higher bolt velocity
as a result of the larger gas ports. This was kind of a problem that
ricocheted down the entire gun, but that mostly got the problem solved. Eventually later versions of the gas ... piston
assembly here would solve this entirely. Over on the right side of the gun we
can see one other significant change, and that was to go from the folding
charging handle of the Mark I, to a fixed charging handle of the Mark II. Now after the war there would be a
significant refit and repair program, and they actually introduced sort of
a new designation, a Bren Mark II/1, in which Mark II guns were modified to
allow them to fit folding charging handles. Because that allowed the gun to
be just a little bit narrower in profile, which was useful for storage, and transportation,
and other relatively benign purposes. And while we're over here, you can
also see the change in sling attachment. The Mark I guns, regular and modified, had sort of this stud that was
used with a snap hook on the sling. The Mark II was given just a simple
standard sling swivel with a plain loop sling. There were no changes to the
markings on the Mark I Modified guns. However, the Mark II guns
were indeed marked "Mark II". Inglis in Canada did manufacture
... guns to the Mark II specification, ... they started with Mark Is, but they
did also build the Mark IIs later on. And so this is an Inglis
marked gun, 1943 dated. Now there would be one more variation of
the Bren gun, and that would be the Mark III. There was a Mark IV that was trialled,
sort of, but never put into production. Mark III Bren guns are effectively, they're kind
of, more or less, a Modified Mark I receiver with a shortened ... Mark II pattern barrel. They would produce a lot of
those, like 57,000 of those, but I don't have an example
of one here to show you. So we'll hold off on that until I get
access to one for a future video. Hopefully you enjoyed taking a look at these. Thanks for watching.
