In the previous article, we described the story of how the Bran machine gun was born. Today we will focus on the technical, so to speak, side of the matter, since any machine gun is a machine, and in this capacity it is interesting, as an example of the human mind and the capabilities of the technology of the corresponding time.
Disassembled machine gun "Bran". All the parts that make up it and the design features are clearly visible. Below there is a stock with a gun carriage, a gas piston with a frame and a trigger is higher, an S-shaped bolt, a cover for a magazine opening, a bolt carrier and other details are even higher.
Let's start with the barrel, because the barrel is the main part of any “shooting machine”. The barrels of the branded Mk I, Mk II and Mk III machine guns are marked Mk I * (asterisk), and, respectively, numbers 2 and 3. This designates the barrel length, which is 635 mm. The barrel has a right-hand groove with 6 grooves 2.23 mm wide and 0.15 mm deep. The thread pitch is 254 mm, which is 33 gauge. The bullet spins up in the barrel in 2, 2 turns and acquires an initial speed of 744 m / s, at a rotation speed of 2930 rpm.
Barrel with carry handle and gas regulator.
Gas regulator.
The total weight of the Mk I and Mk I * barrels is 2.84 kg, while the weight of the Mk III barrel is 2.95 kg. Cone shaped flame arrester, chrome plated. On the left side of the barrel there is a front sight, shifted to the left of the axis of symmetry due to the location of the store. Then comes the gas chamber with a regulator. The chamber has four channels of different diameters, which makes it possible to change the amount of gas discharged into the gas chamber. Under normal conditions, the standard setting No. 2.
In this photo, there are two important details at once: the cover of the magazine opening and the barrel attachment handle.
The barrels of the Mk I and Mk I * differ only in the diameter of the gas regulator, which is larger for the Mk I *. The barrel of the Mk II has a different, more tapered, flash suppressor. The barrels of the Mk III and Mk IV were shortened to 565 mm, so that their weight was reduced to 2.35 kg, and even to 2.2 kg for the Mk IV. Each machine gun crew had two spare barrels. This made it possible, in the event of heating, to replace the hot barrel with a cold one, which, in turn, reduced the thermal erosion of the metal. The replacement was to be made after the shooting of 10 stores, that is, 300 shots!
This is how the barrel is replaced.
The bolt of the machine gun was one of the most technologically laborious parts. It took 270 operations to get it, while the steel block from which it was made had to lose 2.04 kg in weight!
The bolt carrier is separated from the stock.
The machine gun had a Mk I drum-type diopter sight, taken one to one from a Czech machine gun. The drum turns and raises or lowers the sight bar. The scope itself was calibrated from 200 to 2000 yards, in 50 yards increments per division. Later, a simplified sight was installed on the Bran, designed for firing at a distance of 200 to 1,800 yards, with a step of 100 yards in one division.
Completely separated bolt carrier with gas piston guide tube.
The "Bran" machine gun was, in general, a fairly typical weapon with a drive through the exhaust of gases from the bore in the lower part of the barrel. However, in fact, it was very different in design and from the famous "Lewis", and from our no less famous "Degtyarev" DP-27. Both the one and the other had a gas vent mechanism and a barrel that was tightly connected to the receiver. Here, too, there was a receiver with which the barrel was connected, although not rigidly, but with the possibility of replacement. However, the "highlight" of the design was, and, by the way, originally on the ZB vz. 26 machine gun. it was absent that the gas outlet tube, in which, like these two machine guns, the gas piston moved, in fact, also served as a gun carriage, along which, when firing, by the recoil force and the barrel, and the bolt, and the receiver, and the magazine, all rolled back together. That is, the gas outlet tube was rigidly connected not to the receiver, but … only to the butt! And it was on this peculiar carriage, or rather, inside it, that the trigger mechanism was located, but all the other mechanisms that were in the receiver were moved back relative to it when fired, although not very far. This technical solution made it possible to reduce recoil and, accordingly, increase the accuracy of fire. Although, of course, this was achieved by the complication of the design itself and, in particular, the production technology, and increased requirements for the dimensions of the tolerances. By the way, that is why the bipod was attached to the "Bran" precisely to the frame of the gas piston, and not to the barrel.
The bolt of the machine gun was locked upward skewed. For this, there was a corresponding protrusion on the bolt, and a groove on the receiver. At the same time, another design feature was the location of the trigger, which hit the drummer, on … the gas piston frame itself. When fired, the piston retreated, pressed the back inclined side of the trigger on the protrusion in the bolt and it lowered, after which the gas piston, continuing to move back (it had a long stroke), pulled the bolt even further, and he removed the spent cartridge case, which fell down through the hole in the gas piston frame. Now the return spring, which was together with the pusher in the tube inside the butt, came into play and sent the bolt forward. At the same time, the next cartridge was fed from the store, the shutter rose up by the protrusion of the gas piston frame (while the barrel was locked), and the hammer hit the spring-loaded drummer. As for the operation of the trigger mechanism, it boiled down to blocking and releasing the rear of the gas piston (for this, a groove was made in it), and that's it. That is, there was also a movable "trigger" in it, but it did not hit the drummer, but only released the gas piston with a frame in its rear part. Moreover, it is important to note that there were no springs in this machine gun where they could heat up. The recoil spring was recessed into the body of the butt and there it could not get to dust, dirt, or high temperatures.
The scheme of action of the machine gun "Bran".
A characteristic feature of all Holek machine guns was the power supply system from the store, located vertically on them. Moreover, it was not shifted to the left, like a similar magazine for the Madsen machine gun, which is why the sights on it had to be shifted to the left. At the same time, they used small-capacity magazines - 20 rounds, the same as on the American BAR. The first GBS also had a magazine capacity of 20 rounds, but then the British came up with their own, and a successful one, despite the complexity of the task - making a magazine for cartridges with a rim is much more difficult.
Sectional view of the magazine and the shutter.
In addition to this magazine, a 200-round disk magazine with a double-row arrangement of cartridges and a clock spring was also developed. It was impossible to use a standard sight with such a magazine, therefore, such magazines were used on installations for anti-aircraft shooting, when there was a special anti-aircraft sight on it. He weighed 3 kg empty and 5 kg with cartridges. Charging it was quite a laborious task, and it was best done with two people. The magazine opening was covered with a special sliding cover.
Aim.
The bipod of the Mk I machine gun was equipped with legs that could be adjusted in height for ease of operation on rough terrain. The Mk II had already fixed legs. The old-style bipod was put on the Bran L4. The L4A2 uses a bipod made from an alloy previously developed for the Mk IV, but was then abandoned in the early stages of work on this prototype.
The sight is from the side of the drum mechanism of its drive.
A special tripod weighing 13.6 kg was also developed, which made it possible, if necessary, to fire at aircraft. But in 1944 it was rarely used. The horizontal firing angle from this machine was 21 ° on both sides. The elevation angle for vertical shooting was 19 °. Twin Mk I and Terrible Twins, with Motley and Gallows scopes mounted on them, were also used to fire at the aircraft. Moreover, the installations themselves were often called so, which were very popular in North Africa, where, however, they were more often used to combat ground targets than aviation. Later, the British command considered that firing them at German vehicles was a waste of ammunition. They were often mounted on light vehicles, thereby significantly increasing their firepower.
"Bran" with a disk magazine.
As for the latter, it should be noted that the rate of fire is 450-480 rounds per minute, and practically from it you can fire at a rate of 120-150 rounds per minute. The rate of fire for single shots is 40-60 rounds per minute. The fire translator was located on the left, above the pistol grip.
As for the overall assessment of this weapon, the British believe that this is the best light machine gun for a rifle cartridge with a rim. They talk about simple design, reliability, ease of use and convenient barrel replacement. The disadvantages include a relatively large weight, high metal consumption during production and delays in shooting due to the fault of the store, although they were eliminated very easily.
One of the most popular British armored personnel carriers was called the Bran Carrier and was intended to carry 1-2 Bran machine guns and their crews.
The Australians nicknamed it for the characteristic sound of gunshots "grandma's cough", and they also used it very widely. In total, he was or is in service with 25 countries, including India and Pakistan. No one has ever counted second-hand sellers offering it for sale, but there are also quite a few of them.
Photos of "Bren" show it in service even with the armies of those countries that have never bought it, as well as illegal gangs all over the world. They can be seen in photographs of conflicts in the Middle East (Egypt 1956, 1967, the civil war in Lebanon, Cyprus 1974), in Africa (Kenya - the Mau Mau uprising, Biafra, Congo), in Indonesia, India (1947, the war with China), in Afghanistan, and even in the hands of soldiers of the Royal Marines of Britain in the war for the Falkland Islands in 1982, as well as in Operation Desert Storm in Kuwait in 1991. In Europe, it was actively used by the IRA and the Basque organization ETA. Well, a total of 302,000 of them were produced …
