Bren MkI: The Best Light Machine Gun of World War Two

Hey guys, thanks for tuning in to another video on ForgottenWeapons.com. I'm Ian McCollum and today is the first of a multi-part video about the Bren gun. Today we will look at the origins of the Bren pistol and its original early production. And then in a follow-up video a little later, we'll talk about the things that were done to it during World War II, modifications and improvements. And we will continue with a third part about a conversion of the Bren to 7.62 NATO. So, to start with the first (prettiest really) Bren pistol. This dates back to the 1920s, unsurprisingly.

After the First World War, the British Army was interested in finding a replacement for its Vickers and Lewis guns. And they kind of tinkered during the 1920s. They tested almost every weapon that came out in the 1920s. But there was no real concerted testing program, it was just, "Oh... look... there's a

machine

gun." Châtellerault, let's take a look at that. And then let's take a look at the BAR." And by the way they really liked the BAR. ...In the years immediately after World War I, everyone really liked the BAR, but the British never adopted it.

It wasn't until 1930 that there was a real formal push to say, "Okay, we're going to do a test and we're going to find a new

light

machine

gun." And in particular, this new

light

machine gun was to have the task of replacing both the Lewis as a light machine gun and the Vickers as a heavy machine gun. And this is not an out of place requirement. This is exactly what the Germans would do, creating a universal machine gun with both heavy and light employment methods. However, the British were going to do it with a gun fed by a box magazine.

By the way, the third part of the requirement is that they also wanted the weapon to be able to be mounted on vehicles, transport vehicles or armored fighting vehicles. What would eventually become the Universal Carrier, also known as the Bren weapons carrier. A small tracked utility vehicle on which a weapon could be mounted. In any case, in 1930 this really serious program began. And they test all the usual suspects again. They try to test the Darnes, but can't make it in time. They test two versions of the Browning, that is, the BAR. They test SIG's KE-7. ...The control they are testing is the Lewis gun.

The Vickers would play no role in this. ...While they wanted the new weapon...to take on both heavy and light roles, here they were really focusing on light, at least in the testing program. And then they also tested this in Czechoslovakia, the ZB 26. Which, when they got them, was actually a ZB 27, with some slightly improved features. ...Oh, I should too, they also tested the Madsen pistol in .303 and the Vickers-Berthier. And the test reports are quite interesting because you can almost see mustaches moving with excitement through some of these test reports, because this Czech gun performed magnificently well.

To everyone's surprise, as far as I know. The initial test was approximately 12,500 shots between everything that was done with the different weapons. The ZB made it through without any broken parts and with two malfunctions, both of which could be related to the chargers. Now at this point, this is a gun that is in 8mm Mauser. The British, of course, want a .303 caliber gun, but the ZB was being made in 8mm. And... in one of the first tests, they were perfectly happy to choose a different caliber. So at the end of this first test in 1930, they eliminated all but three of the weapons.

They are very excited about the ZB 26 (or 27), but they are also quite happy with the Vickers-Berthier and also the Madsen pistol. They don't like the handling of the Madsen, but it performed fairly reliably. The Vickers-Berthier also showed great promise. So they decided to come back a year later and do a new test. And for that trial they specifically wanted a .303 caliber pistol. So the Brno factory was willing to oblige and in 1931 shipped a converted .303 gun. So, a .303 barrel and a .303 magazine. And it should be noted at this point that the ZB they were working with was very similar to a ZB 26, it had a gas piston that went all the way to the end of the barrel.

And they liked that feature, because what it meant in the original guns was that the bullet had to get this far before the gas came out of the barrel and started moving the action. Which means it's a pretty smooth shooting gun. Because the action of...cycling is delayed until about the time the bullet exits, it is delayed as much as possible. The M1 Garand is similar in this regard. However, what they discovered in this 1931 test is that the gun actually didn't perform that well. He had trouble throwing out, which they attributed to a relatively rushed conversion program to .303.

Had problems with the magazine, the .303 is a rimmed cartridge, the 8mm is rimless. ...This type of conversion will be a bit difficult. They also discovered that the gas port a long way from here didn't work very well with specifically British ammunition. Because the British use cordite because they have to be a little different. And he committed many more fouls than he should have... that's why. What's interesting to me is that the British Ordnance Testing Board was so enamored of the gun that they simply didn't care. I mean, they obviously cared, but normally problems like that would be an easy cause to say, "Okay, the gun's out of testing, forget it.

It won't power, it breaks down, we don't like it, get rid of it." "In this case they were willing to give Brno quite a bit of leeway, relative to what you would expect. ... They basically said, "Oh, well, we know it was fantastic in the rimless 8mm version. "Just take it back, spend a little more time, tweak it a little more and we'll see when you do. "We've fixed it up a little bit because, boy, we really want this gun." It's more or less what you can read in the reports. At the end of this test, they had practically abandoned the Madsen.

They weren't happy with it for a number of reasons and frankly it was a very old design at the time. 1932 arrives and they get another revised version of the ZB. This is now the ZGB pattern pistol, Great Britain, 1932 or 32. The magazine has been improved. They have moved the gas port to approximately this point, where it would remain in the final version of Bren. They put another 19,000 rounds through the gun and have something like 6 malfunctions. All of which could be removed by simply hitting the charging handle. And like one of them is just an edge blocking issue.

And they are delighted, but there are still some things they want more. They want a better tripod setup, because remember, they still have the idea that it will also replace the Vickers gun in service. And the way to do it is to mount it on a tripod and put an optic on it, which, by the way, they ask for an optics mount. And we'll talk about that when we look at the gun up close. So they want a better tripod and they also want 30 round magazines. Because at that time what Brno had given them was a 20-round magazine, which makes sense in 8mm. ...Basically, in all its other versions, the ZB 26 family uses a 20-round magazine.

But the British wanted 30, so that's fine. The ZGB 33 model pistol arrives next year and...it's basically the same gun,...like literally the same test gun, and they've just modified it again. It now has 30 round magazines and tripod attachment points, which we will also look at in a moment. And the British do more tests and say this is pretty good. They discover some problems with Vickers-Berthier that they don't like, so they rule them out of the tests. And... they've pretty much prepared themselves with what will become the Bren, the ZB pistol. Just for fun, they take a second example of the gun, not the one that has already gone through all these tests and modified, but a second model, and they do a 150,000 round endurance test on it.

Something like to see what breaks. And a bunch of recoil springs broke in the course of that. But they said they didn't even realize until they stopped to perform a routine cleaning of the gun as part of this test. And they'd open it up and say, "Oh, the recoil spring broke, huh, we didn't notice." Throw it away, put a new one. With just over 140,000 shots, the... type of lower receiver, if there is such a thing, broke. Again, they didn't stop the gun, but it broke, so they fixed it. And they added some metal to that part of the scheme for when they started full-scale production.

And again, they were really beside themselves with how wonderful this light machine gun was. Thus, in 1935 the British government signed a contract with Brno to license the manufacture of what in 1935 would be known as the Bren gun. It's "Br" for Brno, the factory in Czechoslovakia where it was developed, and "en" for Enfield, the factory in England where it will be made. The license agreement will be valid until 1949, and... for the first 17,000 weapons they will pay a license fee of 3 pounds. That drops to 2 pounds when they get to 40,000 guns. They are permitted to manufacture them... under this license agreement, in the United Kingdom, in its dominions and provinces, and also in Sudan.

They never established production in Sudan. And they are also allowed to sell them to Sudan and Iraq, which is a British protectorate at the time. But they can't sell these things in the commercial market elsewhere. Production would take a while to increase. The first thing they had to do was convert all the drawings to inches, because in Czechoslovakia they had been made in metric dimensions. And there was a little mistake there, the original Enfield production gun turns out to not be entirely interchangeable because they mess up the conversion. This leads to something called the "Enfield inch", which is not a normal standard inch.

Hence the problems. That is a separate topic that we will address later. In 1938 production began. So they get the first official Bren Mark I, built basically as a test sample in Czechoslovakia in the spring of 1937. Enfield began production in September... 1937, and in 1938 the first guns rolled off the line. So... now that we've spent a lot of time going over the backstory on this, let's break it down and let me show you how this really works. The Bren is widely considered, and I think quite rightly, to be basically the

best

light machine gun of this period. The

best

light machine gun of the light machine guns that were made in this style.

And by this I mean guns that are magazine-fed, not belt-fed, and that are fired with a bipod instead of a tripod. ...There was a kind of heyday of these weapons from the 1920s to the 1940s, before everyone decided to adopt the idea of ​​the German universal machine gun. The Mark I Bren is a fairly elegant and feature-rich type of weapon. So we have a stabilization handle back here. So your shooting hand, your strong hand, goes on the grip of the gun, and your support hand holds it to help control the gun. It is mounted on what is actually also a tripod stand.

Then this pin is unlocked (this one is pretty rigid here). With that raised all the way up, the rear handle comes out. ...You can see the style of the socket here, so when you put it on a tripod, there's a lug right there. And then you push this pin back, lock it in place and that locks the gun into the tripod. We also have a folding armrest up here. So you can lower that. There are questions about how useful they really are, but they give you something to pull on the back of the gun while you shoot.

This is marked Bren Mark I here on the side. And this is a very early example, made in Enfield. You have the actual cipher there and the date, 1939. This style of marking would change a little before long. And the serial number is here on the back of the receiver. They were initially made in single prefix batches of 10,000, so A, B and C. This gun was one that was actually... (well, obviously, made in 1939) produced before Dunkirk. Obviously this one survived Dunkirk. Of course, we have a 30-round magazine. There are... here are a couple of slots stamped into the charger.

This is to check the edges of the cartridges to make sure they do not cause edge blockage. This, of course, is for shoulder control and keeping the bullets pointed in the right direction. There is a keep-open tab here, which will lock when the magazine is empty. The gun fires from an open bolt, which we'll get to in a moment. There is a folding, non-reciprocating charging handle here in the Mark I pattern. There is also a dust cover that covers the magazine well. There is a small ball detent here that holds it in the open or closed position.

Dad, right there. There's also a sliding dust cover on the bottom, if you push it. You have to open it to shoot, so you have an ejection port. But if you are not actively using the gun, you can close it and prevent dirt from entering the bottom. The barrel changing mechanism is extremely simple, here we have our locking lever. There is a small spring-loaded button inside. (By the way, protected so you don't accidentally hit it). Pick it up... not fromall 90 degrees. And then, using the nice big handle, you just pull the barrel forward of the gun.

It uses an interrupted thread, and that's what this lever really is, it's the other half of this interrupted thread. So lift it up and the barrel slides out. Locked, the barrel remains in place. Here we have a front pin, just like the one that held the rear stabilization handle in place. This is the front attachment point of the tripod. The bipod normally sits like this. You can rotate the bipod 90 degrees and slide it off the gun. ...This one has a little fat but the legs can extend and retract. And of course, when this is mounted on the gun, you can fold the legs... together and then fold them back or forward, whichever you prefer.

There is a lot to go over about this weapon. On the other side we have a selector switch here. It is marked "A", "S" and "R". And that's automatic in the forward position, safety in the middle position and R for repeat, which is semi-automatic fire, in the rear. There are two dovetail mounts on the side of the gun. The rear holds the iron sights, which we'll get to in a second. The front was intended for an indirect fire sight, as well as a telescopic sight that was under development. Now we will talk about the indirect fire sight separately, because some of them exist and we have access to one.

But that's a little beyond the scope of this video, which is already getting long. The story about magnified optics, the scope for this, is that it was planned, and basically after Dunkirk the whole idea was scrapped. They wanted to simplify weapons. The original idea was to use the number 32 scope and mounting bracket which are the same ones that would go on the number 4 rifle sniper patterns. The idea is that you would have the same scope and mounting bracket, and you would simply swap them between rifles. sniper and light machine guns as long as you have the small mounting bracket for each.

But the whole idea was scrapped. As far as I know, none of the Bren mounting systems were manufactured. And only the first guns have the second dovetail for that scope. Now, the iron sights here are based on a rotating wheel. And as you crank it up, the rear aperture sight will rise. Here you have an aperture sight and the scope markings are on this wheel. (If we can turn the light on correctly, you will be able to see it there.) Therefore, it tells you your range adjustment as you turn the wheel up. It's quite complex, there you have it, 2, 3, 4, etc. (Sorry, there's some old oil too.) Quite complicated rear sight setup, but works well.

Looking down the canyon. I'll come back to the handle in a moment. We have a gas block here in the canyon. It's adjustable, you have four different settings. And they are indicated by the different sized holes there. To change the setting, simply remove the barrel and rotate it to the setting you want. There's a little tab here on the front of the piston that will slide into it, and that makes sure that... the settings there are aligned correctly for the gun to work. If you want to take the... gas port system, you just turn it to where it's halfway between the settings, and then it just pops out of the gun.

Oops, and then I dropped it on the table. The front sight here, of course, is offset to the left, and that is to match the offset with the left rear sight, which is done because the magazine is centered on the top of the gun, so you can't have the you look in the middle. . In practice, this doesn't really cause any major problems. It's a little awkward for a lefty to shoot, but you can actually turn your head over the top of the stock and it's no big deal. Just a minor note, there is a lightning cut in the front sight tower of the guns which were made by Enfield, but not Inglis.

So that's just a little identification trick. And then, of course, one of the distinguishing features of the Mark I Bren is this stainless steel gas block or flame spreader assembly. And the original idea here was that where it is currently fixed in position permanently (or semi-permanently), it was originally going to be a threaded component. So the canyon itself reaches here. You can see the end of the canyon right there (with a little grease and dirt in there, sorry). And the original point was that if it slipped, stainless steel was more resistant to corrosion, so it would help prevent dirt and rust from getting into the gas system.

And then if I had problems, I could just change this, instead of having to change the entire barrel. This pin would have originally been basically a removable spring clip that you could twist, pop the pin out, and then you could unscrew it from the barrel. The other thing they wanted to do with that was make a blank firing version of this...gas block and hider assembly that would be properly gassed for blank firing. It would already have the appropriate restrictor on the front, making it a nice, simple and elegant blank firing system. They never actually did that; in fact, I have a version here that we'll look at in a separate video of the actual blank firing system they used.

But that's why this is this distinctive separate material, a separate component out here. There's another little feature I want to show you, because it's really cool. The barrel carrying handle, of course, is kept vertical, in this way, for removing the barrel or for transporting the weapon. And then it folds to the side when you're shooting. However, you can also pull the handle back and it will unlock, and you push it all the way down and then turn it forward like this. This one doesn't want to snap back in, but what happens is this little tab locks onto a rail on the front of the receiver here and holds it solidly in the down position.

And this was intended to help control the weapon with the support hand when using it in an anti-aircraft role raised on a tripod. It would also be used by troops to fire from the hip supported by a sling. And you have your main hand back here on the grip and your support hand up here on the front grip. And it is a stylish assault-fire style carry handle style. Alright, I have a second example here that I'm going to separate to show you the internal parts, because it's a little bit happier to separate. So first remove the magazine.

The second thing is easy, we are going to open the handle and remove the barrel. The next step we can turn it down and the bipod will come off. So there is only one pin that holds this gun together, and it is a captive pin. And if I take it out, I can remove the entire frame from the lower trigger assembly of the gun. So this has that sliding dust cover, right there. This has the firing mechanism. The recoil spring is captive inside the stock. So you just have this extension rod that will push the... bolt carrier.

Once I have the lower assembly removed from the gun, I will be able to remove the bolt carrier. So gas piston, bolt carrier. The bolt lifts like this. We have a spring-loaded firing pin there. And that's the entire stripped field. This is legitimately one of the fastest and easiest light machine guns to disassemble and reassemble. There are no small parts to lose. And it's actually a really elegant design. Mechanically it is of course identical to the ZB 26. Simply put, it is a toggle bolt. Then, as the whole assembly moves forward, it pushes a cartridge in (these two prongs pick up a cartridge from the magazine).

When the cartridge is full, the bolt will stop but the recoil spring continues to push the operating rod forward. And here you can see the little ramp that pushes the back of the bolt up. This is the locked and battery powered position. And what happens there is this shiny surface on top is wedged into a recess on the top of the receiver. That is, it locks right in front of this piece, this is a hardened locking block. You can see it has a little screw hammered in there, which can actually be replaced. So if the clearance grows too much, you can put a larger locking piece (the term would be locking shoulder) in there and return the gun to service.

This tongue here is the ejector. So when the bolt returns fully with an empty cartridge, the ejector will slide between those two little rails at the top. It will pull the cartridge out of the bolt face and push it down where it is ejected out the bottom of the gun. There's actually a big hole, so when the gun is in the ejection position, it lines up with the bottom of the receiver, right here, giving you an ejection port. When the bolt is forward, that ejection port doesn't exist, but it doesn't matter because the bolt doesn't try to eject.

Now, the way this actually kicks in is that you have your loading/camera sequence. Then the bolt will lift and continue backwards. And when it gets completely into the locked position, like this, this surface on this little tower is going to hit that, right there, which is the firing pin. That will stick out over the face of the bolt. And yes, it is basically a rectangular firing pin, not a round one. That will stick out of the face and shoot. As I mentioned at the beginning, this is fired from an open bolt, so it is normally in this position.

Everything moves forward, cameras, fires. ...(Yes, there we go, there's the firing action with the bolt mounted). And then the gas block injects gas into the front of this piston, which will push the entire assembly rearward. The first thing that will happen is that the bolt locks in place, so the operating rod will move back. And then... the ramp of this hook will act on this surface on the back of the bolt, which pulls it down, just like that. Then you run out of battery, and then everything can go back, extract, and then eject the empty cartridge.

By the time Dunkirk occurred, the British had manufactured around 30,000 Bren guns. By the way, they had also started production at the John Inglis Company, they had hired John Inglis in Canada to make Brens. In... 1938 it was evident that war was coming and they wanted to have redundant manufacturing outside the British Isles. So initially they would be manufactured by Enfield and Inglis. So they had about 30,000 when Dunkirk happened. In the process of evacuating the BEF from mainland Europe, they managed to lose around 27,000 of their 30,000 Bren guns. And that put them in a serious small arms shortage... after Dunkirk.

That, combined with some problems that arose in the early stages of World War II using them in combat, they ran into some problems, problems with the gas system and a number of other things. This would lead to a desire to modify the design, which would lead to a modified version, and then a Mark II version of the Bren pistol. We'll cover them in a future video. I hope you enjoyed this one. Thanks for watching.