Smooth-bore weapons attract the attention of a very large number of people, because such weapons are available to any adequate, law-abiding, adult citizen. However, in addition to civilian weapons, there are options for guns that are called combat. These samples arouse even greater interest among ordinary people, since you can compare the performance characteristics with your own gun, be glad that it is better, well, or give up that it turned out to be worse, not a combat one. Among combat smooth-bore guns, there is also an even more interesting category, in my opinion, namely smooth-bore guns with the ability to conduct automatic fire. Personally, I find it difficult to imagine such a weapon in action, and I hardly imagine shooting from it, especially when it comes to 12 caliber, it would probably even be scary to shoot 2-3 rounds in automatic fire mode, nevertheless, this weapon exists and according to those who happened to get to know him closely, there is no more effective means of destroying the enemy at short distances. Let's try to walk through the three most famous models of such weapons.
A gun with the ability to conduct automatic fire AA-12.
Probably the most famous, or rather the oldest sample of the three described below, is the AA-12. Rather, the name "AA-12" is the name of the latest version of the gun, and before it was created many other, a wide variety of designs of smooth-bore weapons with the ability to conduct automatic fire. At the same time, some of the weapon options were really unique and quite daring. But let's start in order to understand how this weapon was born in the form in which it exists now, and what predecessors it had, which had the right to life with a more detailed study.
Based on his experience in the Vietnam War, Maxwell Archisson began in 1970 the development of smooth-bore weapons specifically for combat use. After seeing how effective a smoothbore weapon can be at short range and in the jungle, Achisson decided to make the gun an even more formidable weapon by giving it the ability to fire automatically. Naturally, the designer did not receive support for such a crazy idea, since for many, both then and now, automatic fire from a 12-gauge rifle seems to be something crazy and suitable only for people whose strength exceeds that of the average person. That is, the weapon was considered “not for everyone,” which means that he was not given the right to life. The designer was not stopped either by the fact that there was no financial help from outside, nor by the lack of understanding of his acquaintances, he walked towards his goal, and very soon he achieved his goal.
Already in 1972, the designer created the first version of the gun with the ability to conduct automatic fire. In his first sample, the designer focused precisely on making his weapon cheap to manufacture and easy to maintain, because a number of parts in this gun with the possibility of automatic fire were borrowed from other models of weapons that were not even close to the guns. The rest, which could not be transferred from other models, was assembled from the simplest parts that can be found in large quantities in any garage of a thrifty owner. So, the receiver of the gun was made in the form of a pipe, inside there was a bolt of the weapon, which could move almost along the entire length of the pipe, which had a length up to the rear of the butt. The designer took the trigger from the Browning M1918 machine gun, the barrel from a 12-gauge gun, and the forend from the M16A1 rifle. The sample was fed from detachable single-row magazines with a capacity of 5 rounds. In general, the weapon turned out to be really very simple and cheap to manufacture, but much more interesting was how it worked.
Anyone who is familiar with the design of the Browning machine gun in 1918 has probably already understood the basic principle of operation of this gun with the ability to conduct automatic fire. The thing is that Atchisson used an automatic system with a free breech, with firing from an open bolt and a prick of the cartridge primer when the bolt was rolling. Thus, the designer managed to solve the main problem of such a weapon, namely, too much recoil when firing. Not only did the bolt have a sufficiently long stroke, but on the way to the breech of the barrel, it lost its speed due to the fact that the powder gases pushed a sleeve towards it, the speed and weight of which was enough to not only stop the bolt, but also give acceleration to him in the opposite direction. Thus, it turned out that part of the energy of the powder gases that pushed the spent cartridge case out of the chamber was spent on stopping the bolt of the weapon and sending it in the opposite direction, which significantly affected the convenience of handling the weapon.
The rather strong recoil of the weapon during automatic fire also created another problem, namely, the magazine falling out when firing under the influence of recoil. In order to eliminate this unpleasant moment, the designer introduced an additional element in his weapon, in the form of a magazine rail, which serves as a kind of support for him. This negatively affected the reloading speed, since the magazine had to coincide with the guide, but at the same time it solved the problem with the magazine falling out. On the same sample, the designer tested a magazine with a capacity of 20 rounds, made in the form of a disk.
In the end, Maxwell Archisson managed to get almost perfect work from his first sample, without failures. However, the problem of the weapon's automation system was that it was limited in the power of the ammunition, in addition, the powder charge, which was permissible for use in these weapons, and the weight of the projectiles varied within very narrow limits. Which, of course, was the negative aspects of the weapon in general. Therefore, the designer abandoned the idea of creating a gun with the ability to conduct automatic fire with such an automation scheme and continued to look further for a solution that would be acceptable for his weapon.
The second version of a smoothbore gun with the ability to conduct automatic fire was an equally interesting sample. Having abandoned the scheme with a free breechblock and a shot from an open breech, the designer decided to make a weapon, relying on a proven and worked-out scheme with the removal of powder gases from the barrel, but locking the shutter not by turning it, but using a locking wedge. The new scheme of the weapon's automation allowed the use of much more powerful ammunition, as well as expanding the range of cartridges that can be used in weapons, even if they are mixed in the store.
Above the barrel of the weapon was a gas piston, which pushed the bolt of the gun back, a tube is placed in the hollow butt of the weapon, in which the bolt moves, compressing the return spring when moving back, and pushed forward by it. The barrel bore is locked when the locking wedge is moved, which engages with the groove under the chamber, thereby locking the barrel bore. Despite the fact that the weapon received a more omnivorous automation system, its recoil increased significantly, and not every person could conduct automatic fire from this sample of a gun. All weapons were fed from the same stores that were developed during the design of the previous model.
Thus, this sample was also not suitable for mass production, since the recoil of this weapon during automatic fire was very high. But despite this, the designer decided to focus on the automation system with the removal of powder gases from the bore, as on the most "omnivorous", concentrating all his efforts on solving the problem of high recoil when conducting automatic fire and he did it, however, it took a very long time before everything was implemented into a working sample.
Until 2000, the designer continued to work on his weapon and, in the end, he managed to create a sample that not only worked flawlessly, but also had quite tolerable recoil. The main feature of the gun was the presence of two return springs of different stiffness, which interact with each other, stretching the recoil moment. This made it possible not only to make the recoil of the weapon more comfortable and significantly increase the resource of the gun. The shot is fired with the barrel bore unlocked.
Actually, it was this sample that became known under the name AA-12, and the Military Police System company took over the production of it, so a gun with the ability to conduct automatic fire can be safely called one of the oldest and at the same time one of the youngest guns among the samples presented.
The gun itself is completely made of steel, the plastic case, in fact, serves as a kind of protective element against the penetration of sand and dust into the weapon and does not experience absolutely any stress when firing. The sights of the weapon are open, adjustable, and consist of a rear sight and a front sight, mounted on high racks. The apparatus is powered by detachable magazines with a capacity of 8 box-type cartridges and drum magazines with a capacity of 20 cartridges. The weight of the final result of Maxwell Archisson's work is 4.75 kilograms. The total length of the weapon is slightly less than a meter - 965 millimeters, the barrel length is 457 millimeters. The gun can be powered by cartridges of 12 gauge with a sleeve length of both 70 millimeters and 76. The rate of fire of the gun with automatic fire is 360 rounds per minute.
I think that the result of the designer's work is more than worthy of respect, because a person put in more than 20 years of his life to achieve his goal, while radically changing the approach to selling his weapon, and such devotion is a very rare phenomenon. If we talk about how successful this sample turned out to be, then it is even difficult to describe something in words. It is enough to look at how a fragile woman is controlled with this sample or how an elderly man shoots, albeit not very effectively, with one hand - all this can be found under the article in the form of a video about a gun with the ability to conduct automatic AA-12 fire.
Shotgun Heckler & Koch CAWS with the ability to conduct automatic fire with a cut-off of three rounds
This weapon especially stands out among the samples presented in the article. The thing is that the CAWS is a gun with the ability to conduct automatic fire with a cut-off of 3 rounds, in addition, this weapon uses not quite ordinary 12-gauge ammunition. And the development of this weapon was carried out within the framework of the program of the US Department of Defense, so this sample is the result of the work of the best designers, although he also had some problems.
In the early 80s of the last century, a program was launched in the United States, the main task of which was to create a smooth-bore 12-gauge weapon capable of using ammunition more powerful than standard 12/70 cartridges, equipped with both classic projectiles and feathered arrows from tungsten alloy. The Heckler & Koch company joined the work on the new weapon, which undertook to sell the weapon, and Winchester was assigned to deal with the ammunition. Naturally, other companies also took part in the work, it was very profitable business, but all the main work was commissioned and implemented by only two arms firms. The result of the work was a rather interesting sample, which, unfortunately, never began to be mass-produced. At the same time, both weapons and ammunition for it had already been created, but the project was frozen due to the fact that it was not possible to obtain the required results from ammunition with an arrow in a container, and this was the main focus of the program, although, in my look, closing this project was a very big mistake.
The weapon is a sample of a smoothbore shotgun in a bullpup layout powered by a detachable box magazine with a capacity of 10 rounds. The cartridges themselves are a slightly different ammunition than the usual 12-gauge cartridges. Based on a 76 mm long sleeve, these ammunition is designed for a more powerful powder charge, which would never even occur to a hunting cartridge. In addition to the fact that the cartridge case has thicker walls, the groove has a protruding rim, the purpose of which is to strengthen the design of the cartridge case, and also to make it impossible to use the cartridge in a smooth-bore civilian weapon. In general, there were a lot of options for a variety of ammunition for this weapon, but it makes no sense to list them, since most of them did not live up to expectations, and shot and bullet cartridges are already in a wide variety of variations.
The weapon itself was built according to a not quite traditional automatic scheme with a short barrel stroke, and the barrel bore is locked when the bolt is turned by its engagement with the barrel, which allows the weapon frame to be unloaded. The very same automation scheme works as follows. When fired, the bolt and the barrel of the weapon are locked together, because the powder gases, pushing the sleeve back, set in motion both the bolt and the barrel, forcing them to move back together. The barrel, having a stiffer spring than the one that the bolt carrier has, begins to slow down more quickly, as a result of which the bolt carrier overtakes the bolt-barrel group, moving more quickly backward. In the bolt carrier there are shaped slots, which include a pin threaded through the bolt of the weapon. It is thanks to the interaction of these elements that the bolt begins to rotate around its axis, leaving the grip with the barrel. Thus, the barrel of the weapon slowly stops, and the bolt group continues its movement backward, removing the spent cartridge case from the chamber. Having thrown out the spent cartridge case, the bolt group continues to move, and its course is much longer than can be found in other types of weapons. This is done in order to stretch the recoil moment, as well as reduce the rate of fire in automatic mode. While the bolt group moves backward, the barrel moves forward under the influence of its return spring. Everything is calculated in such a way that the barrel of the weapon is at its front end point just when the bolt group arrives at its extreme rear point. Thus, the weight of the moving barrel also at least slightly compensates for the recoil force when firing, something vaguely reminiscent of balanced automation is obtained. While the bolt group, under the influence of the return spring, begins to move forward, a new cartridge of the weapon is removed from the store, and it is sent into the chamber of the gun. The bolt enters the breech of the weapon barrel and stops, while the bolt carrier continues its movement for some time. When the bolt carrier moves back, the pin passing through the bolt interacts with the shaped cutouts in the bolt frame, which leads to the bolt turning and engages in engagement with the barrel, which locks the barrel bore of the weapon.
But this is only half of the description of the automation of this weapon. The scheme of operation of automatic equipment with a short barrel stroke is implemented for ammunition that is more powerful than the usual 12-gauge hunting cartridges, and will not work with conventional cartridges, since there is simply not enough energy to operate the automation. Nevertheless, the designers took care of the fact that the weapon would have the ability to shoot with conventional ammunition 12/70 and 12/76. For this, an additional automation scheme is provided in the design of the weapon, namely, an automation based on the use of a part of the powder gases discharged from the barrel bore. A gas engine is installed on the movable barrel, which is turned on if weak ammunition is used. When to work and when not to work, this mechanism is determined by an inertial valve, which remains closed at a sufficient speed of the barrel of the weapon and opens if the rollback speed of the barrel is insufficient. A gas piston connected to the bolt carrier of the gun, having received a portion of the powder gases from the barrel bore, pushes the bolt carrier back, which first leads to the bolt turning and its release from the clutch with the barrel, and then moving all the way back and compressing the return spring. The barrel of the weapon may not reach its extreme rear point, but in any case it will be in the forward position, when the bolt, having moved back and throwing out the spent cartridge case, begins its movement in the opposite direction, removes a new cartridge from the chamber and rests against the breech part of the trunk. Locking takes place thanks to the same curly cutouts on the bolt frame and a pin in the bolt. In such a rather interesting way, the "omnivorous" ammunition was realized in weapons, but in production it resulted in a serious amount.
Oddly enough, but all this happiness with a double automation system weighs relatively little. The weight of the weapon without cartridges is 3, 7-3, 86 kilograms, depending on the length of the barrel, which is still the smallest weight among smooth-bore guns with the ability to conduct automatic fire. The length of the weapon is equal to 762-988 millimeters, inversely, depending on which barrel is installed in the weapon, the CA barrel can be from 457 to 685 millimeters long. The weapon is fed from detachable box magazines with a capacity of 10 rounds 12/76 or 12/70, including those ammunition that is designed specifically for this weapon. Due to the long stroke of the bolt group of the gun, the rate of fire is 240 rounds per minute, which has a positive effect on the control of the weapon, provided that the weight is not very large and the recoil is strong enough.
As noted above, the development of this weapon was already at its final stage, when the US Department of Defense canceled the project. The main task of the project was the use of feathered sub-caliber projectiles made of tungsten alloy in order to achieve the maximum possible effective range of weapons and high accuracy. It was with these ammunition that the project had problems, since they did not reach the required characteristics. In general, the project itself was interesting without these cartridges. Naturally, the weapon turned out to be quite expensive to manufacture, and one could not count on the wide distribution of this sample in view of its specificity, nevertheless, in my opinion, it was not worth completely curtailing the development, after all, a lot of money was spent. In the end, this weapon could be deprived of the ability to conduct automatic fire, and given to the civilian market along with more powerful ammunition, I think that people would only be happy with such a unit. Probably, the US Department of Defense has too much money, since it is so easy for them to start and close quite expensive projects, receiving minimal benefit from this in the form of experience gained by the designers.
American-South Korean version of the USAS-12 automatic fire gun
The last sample we will look at in this article is a weapon sample that was designed within the walls of the small company Gilbert Equipmnt Co. Rather, it was designed by one of the designers - John Trevor, but he did not dare to promote his weapon alone. For a long enough time, the company was looking for production facilities to establish mass production of this gun, but no one in the United States was interested in this weapon, realizing its specificity and the fact that it would not enter the civilian market. In Europe, company representatives were also shown the door. In the end, it was possible to interest the South Korean company Daewoo, which not only took up the production of this weapon, but also improved it, making it more reliable and comfortable to use.
The main markets for weapons were the countries of Asia, and later the United States, where the assembly of the gun from South Korean parts was established. There was an attempt to smuggle this model of a smoothbore gun into the US civilian market, but the idea failed, as the "Bureau of Alcohol, Tobacco and Firearms Control" did not pass this sample, suggesting to deprive it of the possibility of automatic fire. And this is the main feature of the weapon, and only thanks to the possibility of automatic fire with a gun can some of its other shortcomings be forgiven. And he has plenty of shortcomings. First of all, it is the heaviest sample among all smoothbore guns with the ability to conduct automatic fire, its weight is 5.5 kilograms. However, the large weight of the weapon makes it more controllable when conducting automatic fire, so here you can look at the whole thing from both sides. The dimensions of the weapon are also considerable. The length of the gun is 960 millimeters with a barrel length of 460 millimeters. The weapon is fed from detachable magazines with a capacity of 10 rounds 12/70 or 12/76 or drum-type magazines with a capacity of 20 rounds. The rate of fire from the sample is 360 rounds per minute.
Interestingly, the sample is easily adaptable both for firing from the right shoulder and from the left. The weapon has duplicated controls on both sides, the shooter himself chooses the side of the ejection of the spent cartridge case, and switching is carried out even without disassembling the weapon and can be done literally in a second. The designers have worked out this question inside and out. The bolt handle is moved far forward, and, in fact, is not the bolt handle, but the handle of the gas piston of the weapon, it can be rearranged both to the left and to the right side. In this case, the handle is not rigidly connected to the details of the weapon and is motionless during firing. Although I would still not count on complete immobility, since anything can happen and a handle that was immobile, for example, due to work hardening, can become very mobile and move with the bolt. So it's better not to put your fingers under the shutter handle. The rifle sights are open. The rear sight is mounted on a handle for carrying weapons, on which alternative sights can be installed, the front sight is mounted on a high rack. The weapon does not have any elements that would fit the anatomy of the shooter.
As it is already clear from what is written above, the basis for the operation of the USAS-12 rifle automation was a scheme using powder gases from the barrel. To be honest, a lot of solutions in this weapon were "licked" by the AA-12 gun, although what was used in the AA-12 was also the features of more than one weapon, so to say that something was redrawn all the same it is impossible. To ensure a more comfortable recoil when firing back, a long bolt stroke of the weapon is used, as well as the accumulation of momentum through the interaction of two springs of different stiffness and length. Actually, all this can be seen from the butt of the weapon, which has an unjustified, at first glance, thickness. Locking the bore of the weapon occurs when the bolt is turned and it is engaged with the breech of the barrel by the lugs.
It was interesting to solve the problem of ejection of the magazine when conducting automatic fire from the weapon by recoil. Unlike the AA-12, where the gun magazine rests against the guide behind it, in the USAS-12 the gun magazine is installed in a more familiar way. This is facilitated by the fact that the gun itself has a decent weight, which makes the recoil not so sharp, as well as the design of the gun, in which the magazine "sits" deep enough into the weapon.
Generally speaking, the weapon turned out to be quite good. Despite the fact that it has a fairly large weight, it is much more convenient in comparison with the previous versions, since it has a lower recoil when firing in automatic mode. Plus, the South Korean company made sure that the production of weapons was as cheap as possible and the quality of the gun did not suffer. It is also interesting that some variants of this smoothbore gun are even equipped with a bipod when using a bullet cartridge, and in addition to the bipod, you can hang a lot of things on the weapon. However, this does not make the USAS rifle any less specific than it is. Too large and heavy, this weapon loses its main advantage, namely effective use in confined spaces, or rather hitting the enemy remains as effective, but the fighter's maneuverability suffers and suffers greatly. However, this drawback is inherent in all three models of smooth-bore guns with the ability to conduct automatic fire, which are described in this article.
In general, such a weapon, in my opinion, fully justifies its existence. The only thing that confuses is the dimensions of common samples and their weight. Apparently, not all designers understand that small dimensions are an indisputable plus of such samples. Although it will be much more difficult to implement the same automation schemes in a more compact weapon while maintaining a tolerable recoil, the designers have not tried all the options for reducing the recoil of weapons when conducting automatic fire. In general, we will wait for new versions of this indisputably useful type of weapon, but this time those from which it would not be scary to shoot. Well, I would also like, of course, to see domestic developments in smoothbore guns with the ability to conduct automatic fire.
