Tank gun caliber 140 millimeters
By the middle of the last century, the development of weapons tanks reached its peak in the field of calibers. In our country and abroad, several models of heavy tanks armed with 152 mm caliber guns appeared. Attempts were made to install on a tracked armored vehicle with a turret and more serious weapons, but they were unsuccessful. Moreover, already in the sixties, the military and tank builders realized that guns of 152 or 155 millimeters were even redundant for a modern tank and therefore all modern vehicles were equipped with 120- or 125-mm guns. Nevertheless, from time to time there are projects concerning tools of a larger caliber. So, in the late eighties at the Leningrad Kirov plant was created an experimental tank "Object 292". An armored vehicle based on the T-80 tank carried a new turret with a 152 mm rifled gun. However, a number of technical and economic reasons did not allow the project to advance further than the tests of the first prototype.
NATO guns
At about the same time that the Soviet "292 Object" was being created, several European countries were discussing the possibility of developing a new weapon, one for their tanks. As the caliber was considered as the usual 120 millimeters, and more solid 140. It is noteworthy that the result of the negotiations was a rather interesting approach to the creation of new guns. According to the memorandum signed by the USA, France, Germany, and Great Britain, all countries could develop their own tank guns, but the parameters of ammunition, which were the same for all, were stipulated. In addition, the dimensions of the breech breech, some nuances of the chamber structure and parameters of the propellant charge were standardized: pressure in the bore, etc. In other words, an international agreement meant the development of several new guns, designed for a single standard shot. The first standard ammunition was the APFSDS armor-piercing pierced projectile.
In the late eighties, it was planned that the new guns, created by the program FTMA (Future Main Tank Armament - " weapon tank of the future "), will become the main armament of tanks of NATO countries. The first such tanks were supposed to go to the troops tentatively at the beginning of the XXI century. From the United States in the creation of new guns of NATO, several companies participated, including Rockwell and Lockheed. In the UK, a similar task was assigned to the Royal Ordnance Factory Nottingham and several related businesses. France and Germany were represented in the program by GIAT Industries and Rheinmetall, respectively. In the course of research and design work, all participating firms studied a variety of issues. The greatest attention was paid to the development of new 140-mm guns on existing tanks. For example, the German "Rheinmetall" tried to install his gun on the tank Leopard 2.
USA, ATAC project
The result of the work of American engineers was the ATAC complex (Advanced TAnk Cannon - "Perspective tank gun"), which consisted of a smooth-bore gun XM291, automatic loader XM91 and a number of related equipment. In the future, this complex was planned to be installed on the upgraded M1 Abrams tank in the course of the next work to improve it. For this reason, a CATT-B test bench (Component Advanced Technology Test-Bed - “Test bench for testing new technologies and units”) was created to test the cannon. CATT-B was a significantly modified M1A1 tank chassis with a new suspension, electronics, etc. Prior to the completion of work on this stand, the XM291 gun was installed on the stationary unit and on the modified tower of the Abrams tank.
The XM291 gun was a smooth-bore tank gun caliber 140 millimeters with separate-sleeve loading. The barrel was equipped with a heat shield. With the new 140-mm split-shot, the muzzle energy of the XM291 cannon was about twice as high as the same parameter of the 120-mm M256 cannon mounted on the latest American tanks. At the same time, thanks to the use of the original construction of the cradle and the recoil devices, it was possible to ensure a substantial weight saving. The larger-caliber gun on the 91 kilogram was lighter than the old M256. For unification with the existing tank guns, XM291 was equipped with a detachable barrel, and the design of the breech part allowed replacing the 140-mm barrel with 120-mm with the corresponding technical and tactical consequences. Thus, the XM291 cannon, if necessary, could use both new powerful ammunition and old, available in sufficient quantities.
According to NATO standards, the ammunition for the guns was planned to be placed outside the fighting compartment, in the stern niche of the tower. The XM91 mechanism, created in the Bennett laboratory of the ground forces, had the ability to automatically select the desired projectile from the ammunition and feed it to the gun. For greater safety of the crew, the projectile and the shell were fed to the gun through a small sleeve in the armor wall between the fighting compartment and laying. At the same time during the ramming, the projectile was additionally covered with a metal curtain. During the tests, the automatic loader XM91 showed a good pace of work - it provided up to 12 rounds per minute. Up to 22 shots of 140 mm caliber or 32-33 shells and 120 caliber sleeves could be placed in the ammo pack, the size of which corresponded to the aft tower niche of the Abrams tank.
In addition to the gun, automatic loader and related equipment specifically for the ATAC complex, three variants of shots were created. All of them were completed with a single sleeve with the same charge of gunpowder. Structurally, the case with gunpowder was an enlarged sleeve for 120-mm guns. The range of ammunition for XM291 looked as follows:
- XM964. Subcaliber armor-piercing projectile;
- XM965. Cumulative fragmentation armor-piercing;
- XM966. Training equipment that simulates both versions of ammunition.
As of 2000, the ATAC gunnery complex has been tested. A little later, representatives of the US military department joined the development firms. However, the XM291 cannon still remains a purely experimental sample. When tested, some technical problems emerged, such as too much recoil energy. Apparently, the work on improving the cannon is still ongoing, but with much less intensity. The beginning of serial production was postponed several times, and at present there is no reason to expect the re-equipment of American tanks. Probably, in the near future, American armored vehicles will be equipped with 120 mm caliber guns, and the new 140-mm gun will remain an experiment. In any case, back in the mid-2000s, the financing of the ATAC project was greatly reduced.
United Kingdom
In 1989, Britain began two programs to develop advanced 140-mm guns. One of them was carried out by the Defense Research Agency (DRA), the other by the firm Royal Ordnance. It is noteworthy that in the early stages the second project was an initiative of the developer company and did not have government support. Regardless of the peculiarities of their beginning, both projects went at a good pace and in the early nineties, the first tests were conducted.
Both British-made 140-mm guns were somewhat similar. This was affected by the agreement on standard ammunition. However, there were noticeable differences. First of all, different designs recoil devices. According to reports, the DRA followed the path of increasing the degree of unification of the new weapon with the existing ones, and Royal Ordnance tried out a new system. The general scheme of the barrel, such as the presence of a heat shield, a purge system after the shot, the ability to quickly replace the barrel, etc., was the same for both guns. As far as is known, both British design organizations worked on their projects of automatic loaders, but they did not reach the tests.
In the 1992 and 1993, the DRA and Royal Ordnance 140-mm guns, respectively, were tested. Shooting was conducted with a standard APFSDS projectile. The total number of test shots exceeded two hundred. In the course of these tests, the advantages of the new tools became clear. First of all, there was an increase in armor penetration. 140-mm gun in the same conditions punched on 40% more armor than the available guns caliber 120 mm. Calculations showed that by changing the material of the armor-piercing projectile, it is possible to further increase its penetration qualities.
However, during the tests, the alleged problems of the new guns were confirmed. Due to the increased energy of the powder gases, the recoil has increased significantly. This led to the fact that both British development companies were forced to admit the lack of effectiveness of recoil devices. It is worth noting that the recoil parameters of the guns made it possible to install them on promising tanks, designed with account of the new loads. However, the modernization of the existing technology was out of the question. The use of new tools on existing tanks threatened damage to the details of the design of both the tank itself and the gun.
The result of testing both guns was a large amount of information, as well as a recommendation to continue work on this topic, but taking into account the requirements regarding the installation of guns on existing tanks. DRA and Royal Ordnance did not have time to actively engage in updating projects. The fact is that after the collapse of the Soviet Union, the British command lost interest in the new tank guns. The generals decided that in the near future there will definitely not be major tank battles and 140-mm guns are not needed. In turn, in the course of possible military conflicts, the existing 120 caliber tank guns of millimeters will suffice. Work on the British 140-mm guns first slowed down and then stopped.
Germany, project NPzK-140
Unlike the British, German designers from Rheinmetall immediately took into account the possibility of installing a new gun on existing Leopard 2 tanks. At the same time, almost immediately after the start of the development of the new cannon, called NPzK-140, it became clear that this would require completely reworking the turret of the tank. This need was due to both the calculated dimensions of the gun itself, and the placement of the newly designed automatic loader. However, the creation of the new tower was postponed indefinitely: in Rheinmetall it was decided that it was first necessary to finish all the work on the cannon and only then make the tower so that it would not have to constantly make adjustments to its design.
At the final design stage, the NPzK-140 gun was a typical tank weapon, differing from the others only in caliber. At the same time, several original solutions were applied to its design. For example, to ensure compatibility with the most convenient version of the automatic loader, the gun was equipped with a bolt with a vertically falling wedge. Also had to significantly rework the ejector gun and equip it with new recoil devices. The last task was one of the most difficult. Due to twice the energy of the powder charge of a standard shot, the recoil increased significantly. But the chassis of the tank "Leopard-2", which in the future could be equipped with a new gun, was not adapted to such loads. Nevertheless, Rinmetall's constructive feeds eventually managed to reduce the calculated return to acceptable values.
Despite certain successes in the design, the new NPzK-140 140 gun never went into the series. At the beginning of the two thousand years, a test stand was made and six copies of the gun itself. Tests of these guns went with varying success, but in the end the project was closed. NPzK-140 in the current state was considered inconvenient and unfinished. Not wanting to spend money on fine-tuning the new weapon, the German military chose to refuse the order. Some developments on this project, primarily of a technological nature, were later used to create the Rh-120 LLR L / 47 tool.
France
American, German and British projects tank guns caliber 140 millimeters were the most successful and reached the stage of testing. In the remaining state party to the agreement on the FTMA program - France - things went a little worse. For example, the French company GIAT Industries, experiencing a number of technical and technological problems, eventually abandoned the creation of its own tool. Nevertheless, she took an active part in other projects and helped British and German enterprises. In recent years, rumors have been circulating about the resumption of the French project, which now has old goals: to create a new weapon for promising European tanks. Despite the available developments, full-fledged news about this project is unlikely to appear in the near future.
Outside of NATO
At the same time with the USA, Great Britain, Germany and France, other countries that are not part of the North Atlantic Alliance became interested in the issue of increasing the caliber of tank guns. The motivation was exactly the same: the increase in caliber promised a big increase in basic combat qualities, and this advantage more than covered all the concerns about the high cost of development and construction or technical problems associated with high energy of the shot.
Switzerland
Interestingly, Swiss engineers from Swiss Ordnance Enterprise (SOE) began developing their 140-mm gun a bit earlier than the NATO countries. Apparently, Switzerland was counting only on its own strength and, seeing foreign advances in this direction, decided to start a similar project too. The construction of the Swiss cannon began in the mid eighties. It should be noted that when developing a new tank gun, it was considered not as a full-fledged armament for promising and modern tanks, but as an experimental model for determining the appearance of a gun and developing new technologies. Nevertheless, even with such views, the possibility of mounting a new gun on Pz 87 Leo tanks (licensed by Leopard 2 of Swiss production) was taken into account.
There is evidence that the basis for the new tank gun caliber 140 millimeters was taken gun Rheinmetall Rh-120, which was originally recruited tanks "Leopard-2". For this reason, the main features of the appearance of the new gun resemble the original Rh-120. At the same time, several solutions were applied to reduce returns. A few years before the foreign projects of similar guns, the Swiss designers not only equipped their gun with new anti-recoil devices, but also used a muzzle brake. The latter consisted of several rows of holes near the muzzle. According to some sources, the efficiency of the muzzle brake exceeded 60%. In addition, due to the location of its holes at some distance from the muzzle, a more efficient use of powder gases was provided, because after passing through the holes of the brake, the projectile continued to receive energy from the gases for some time.
For the new gun, it was planned to create several types of separate-sleeve ammunition, but the main one was the armor-piercing subcaliber, for use with which the propelling charge was optimized. About ten kilograms of gunpowder were placed in a combustible sleeve. In addition, about five kilograms were attached directly to the projectile. Thus, the propellant charge was divided into two parts in a separate-sleeve ammunition. It was assumed that in cumulative or fragmentation shots only the charge placed in the sleeve would be used. Swiss-made ammunition had a serious difference from the shots described in the agreement between the NATO countries. Their sleeves had a smaller length and a larger diameter. According to the official data of the company SOE, in the future, if necessary, it would be possible to change the design of the cannon chamber and the shape of the sleeves for unification with NATO shells.
All technical solutions aimed at reducing the recoil impulse ultimately led to the possibility of mounting a new 140-mm cannon on the Leopard-2 tank. However, first the tests were carried out on a special stand. The new Swiss gun fired the 1988 of the year for the first time in the summer. At the same time, all the necessary data were collected and some modifications of its design were carried out. By the autumn of next year, an experimental vehicle with an updated turret and a new 87-mm gun was assembled on the basis of the serial tank Pz 140 Leo. During the firing at the stand and as part of the tank’s armament, the new gun showed more than interesting results. For example, from a distance of a kilometer, a sub-caliber projectile designed for it was pierced to a meter (!) Of homogeneous armor.
Despite successful tests, the new gun did not go into the series. The reason for this end of the project was the high cost and complexity of the gun, as well as the lack of prerequisites for its launch. In the early nineties, all European countries, due to the collapse of the USSR, reduced defense spending and the purchase of new weapons. The Swiss project 140-mm tank gun added to the list of closed as superfluous and expensive work. According to reports, over the next years, prototypes of guns were used in various test programs, but it was emphasized that this is a purely experimental weapon and Switzerland does not intend to use it for military purposes.
Ukraine, the gun "Bagira"
In the second half of the nineties, a country joined the creation of promising 140-millimeter cannons, from which they were unlikely to expect such work. The Kiev design bureau "Artillery armament" has developed a tank gun of increased power 55L "Bagheera". It is argued that this weapon can be installed on any tank of the latest models of Soviet, Russian or Ukrainian production and significantly improves its fighting qualities.
Available technical information about Bagheera is limited to a few numbers. It is known that with a barrel length of seven meters (50 caliber), the 55L can accelerate a seven kilogram sabot to speeds of the order of 1850-1870 meters per second. The declared armor penetration is up to 450 millimeters at a meeting angle of 60 degrees. Shooting distance was not specified. From the official data of the Design Bureau Artillery Armament, it can be concluded that at least two types of shots were created for the Bagheera. Perhaps firing armor-piercing subcaliber or high-explosive fragmentation shots of separate-cartridge loading.
Any information about the 55L “Bagheera” testing is missing. From the photos on the official website of the developer organization, it is possible to draw a conclusion regarding the manufacture and installation of an experimental gun on a test bench. Information about the purchase of tools also missing. Probably, over the past years, “Bagheera” has not interested potential buyers.
Caliber and expediency
As we see, all projects of tank guns of new-caliber 140 millimeters are faced with the same problems. First of all, this is a super-efficient payoff, which could not be fully compensated with the use of old practices. Of course, in the practice of tank building, more serious calibers with corresponding returns were used, but all the new tools were intended to modernize the existing equipment, which was simply not calculated for such loads. Technical features of a larger-caliber gun entail a number of consequences, such as the need for more robust construction details of the entire tank, a more powerful engine, etc. Ultimately, all this affects the price of the finished tank.
The second controversial point of the 140-mm tank gun concept concerns its tactical features. On the one hand, such weapons have significantly higher armor penetration characteristics in comparison with the usual 120- and 125-mm guns. At the same time, it is not possible to fit the bulk combat with 140-millimeter shots into the dimensions of a modern tank. This will lead to a reduction in ammunition and the corresponding tactical consequences. Confronting the power of the gun and the number of portable shots is the subject of a separate dispute.
In general, 140 caliber tank guns of millimeters, like many other types of weapons, have both pros and cons. In the current conditions, when the development of tanks is not as intense as in previous decades, the use of new calibers looks like an unreasonable measure. It seems that the military of the leading countries will prefer to remain with sufficient and mastered 120 and 125 caliber millimeters, while more serious systems will remain a sign of self-propelled artillery installations.
On the materials of the sites:
http://army-guide.com/
http://globalsecurity.org/
http://defense-update.com/
http://btvt.narod.ru/
http://arrows.newmail.ru/
http://vadimvswar.narod.ru/
http://articles.janes.com/
http://rheinmetall-defence.com/
http://kbao.com.ua/
"292 Object"
NATO guns
At about the same time that the Soviet "292 Object" was being created, several European countries were discussing the possibility of developing a new weapon, one for their tanks. As the caliber was considered as the usual 120 millimeters, and more solid 140. It is noteworthy that the result of the negotiations was a rather interesting approach to the creation of new guns. According to the memorandum signed by the USA, France, Germany, and Great Britain, all countries could develop their own tank guns, but the parameters of ammunition, which were the same for all, were stipulated. In addition, the dimensions of the breech breech, some nuances of the chamber structure and parameters of the propellant charge were standardized: pressure in the bore, etc. In other words, an international agreement meant the development of several new guns, designed for a single standard shot. The first standard ammunition was the APFSDS armor-piercing pierced projectile.
In the late eighties, it was planned that the new guns, created by the program FTMA (Future Main Tank Armament - " weapon tank of the future "), will become the main armament of tanks of NATO countries. The first such tanks were supposed to go to the troops tentatively at the beginning of the XXI century. From the United States in the creation of new guns of NATO, several companies participated, including Rockwell and Lockheed. In the UK, a similar task was assigned to the Royal Ordnance Factory Nottingham and several related businesses. France and Germany were represented in the program by GIAT Industries and Rheinmetall, respectively. In the course of research and design work, all participating firms studied a variety of issues. The greatest attention was paid to the development of new 140-mm guns on existing tanks. For example, the German "Rheinmetall" tried to install his gun on the tank Leopard 2.
USA, ATAC project
The result of the work of American engineers was the ATAC complex (Advanced TAnk Cannon - "Perspective tank gun"), which consisted of a smooth-bore gun XM291, automatic loader XM91 and a number of related equipment. In the future, this complex was planned to be installed on the upgraded M1 Abrams tank in the course of the next work to improve it. For this reason, a CATT-B test bench (Component Advanced Technology Test-Bed - “Test bench for testing new technologies and units”) was created to test the cannon. CATT-B was a significantly modified M1A1 tank chassis with a new suspension, electronics, etc. Prior to the completion of work on this stand, the XM291 gun was installed on the stationary unit and on the modified tower of the Abrams tank.
The XM291 gun was a smooth-bore tank gun caliber 140 millimeters with separate-sleeve loading. The barrel was equipped with a heat shield. With the new 140-mm split-shot, the muzzle energy of the XM291 cannon was about twice as high as the same parameter of the 120-mm M256 cannon mounted on the latest American tanks. At the same time, thanks to the use of the original construction of the cradle and the recoil devices, it was possible to ensure a substantial weight saving. The larger-caliber gun on the 91 kilogram was lighter than the old M256. For unification with the existing tank guns, XM291 was equipped with a detachable barrel, and the design of the breech part allowed replacing the 140-mm barrel with 120-mm with the corresponding technical and tactical consequences. Thus, the XM291 cannon, if necessary, could use both new powerful ammunition and old, available in sufficient quantities.
According to NATO standards, the ammunition for the guns was planned to be placed outside the fighting compartment, in the stern niche of the tower. The XM91 mechanism, created in the Bennett laboratory of the ground forces, had the ability to automatically select the desired projectile from the ammunition and feed it to the gun. For greater safety of the crew, the projectile and the shell were fed to the gun through a small sleeve in the armor wall between the fighting compartment and laying. At the same time during the ramming, the projectile was additionally covered with a metal curtain. During the tests, the automatic loader XM91 showed a good pace of work - it provided up to 12 rounds per minute. Up to 22 shots of 140 mm caliber or 32-33 shells and 120 caliber sleeves could be placed in the ammo pack, the size of which corresponded to the aft tower niche of the Abrams tank.
In addition to the gun, automatic loader and related equipment specifically for the ATAC complex, three variants of shots were created. All of them were completed with a single sleeve with the same charge of gunpowder. Structurally, the case with gunpowder was an enlarged sleeve for 120-mm guns. The range of ammunition for XM291 looked as follows:
- XM964. Subcaliber armor-piercing projectile;
- XM965. Cumulative fragmentation armor-piercing;
- XM966. Training equipment that simulates both versions of ammunition.
As of 2000, the ATAC gunnery complex has been tested. A little later, representatives of the US military department joined the development firms. However, the XM291 cannon still remains a purely experimental sample. When tested, some technical problems emerged, such as too much recoil energy. Apparently, the work on improving the cannon is still ongoing, but with much less intensity. The beginning of serial production was postponed several times, and at present there is no reason to expect the re-equipment of American tanks. Probably, in the near future, American armored vehicles will be equipped with 120 mm caliber guns, and the new 140-mm gun will remain an experiment. In any case, back in the mid-2000s, the financing of the ATAC project was greatly reduced.
United Kingdom
In 1989, Britain began two programs to develop advanced 140-mm guns. One of them was carried out by the Defense Research Agency (DRA), the other by the firm Royal Ordnance. It is noteworthy that in the early stages the second project was an initiative of the developer company and did not have government support. Regardless of the peculiarities of their beginning, both projects went at a good pace and in the early nineties, the first tests were conducted.
Both British-made 140-mm guns were somewhat similar. This was affected by the agreement on standard ammunition. However, there were noticeable differences. First of all, different designs recoil devices. According to reports, the DRA followed the path of increasing the degree of unification of the new weapon with the existing ones, and Royal Ordnance tried out a new system. The general scheme of the barrel, such as the presence of a heat shield, a purge system after the shot, the ability to quickly replace the barrel, etc., was the same for both guns. As far as is known, both British design organizations worked on their projects of automatic loaders, but they did not reach the tests.
In the 1992 and 1993, the DRA and Royal Ordnance 140-mm guns, respectively, were tested. Shooting was conducted with a standard APFSDS projectile. The total number of test shots exceeded two hundred. In the course of these tests, the advantages of the new tools became clear. First of all, there was an increase in armor penetration. 140-mm gun in the same conditions punched on 40% more armor than the available guns caliber 120 mm. Calculations showed that by changing the material of the armor-piercing projectile, it is possible to further increase its penetration qualities.
British advanced tank armament mounted on the Centurion chassis
However, during the tests, the alleged problems of the new guns were confirmed. Due to the increased energy of the powder gases, the recoil has increased significantly. This led to the fact that both British development companies were forced to admit the lack of effectiveness of recoil devices. It is worth noting that the recoil parameters of the guns made it possible to install them on promising tanks, designed with account of the new loads. However, the modernization of the existing technology was out of the question. The use of new tools on existing tanks threatened damage to the details of the design of both the tank itself and the gun.
The result of testing both guns was a large amount of information, as well as a recommendation to continue work on this topic, but taking into account the requirements regarding the installation of guns on existing tanks. DRA and Royal Ordnance did not have time to actively engage in updating projects. The fact is that after the collapse of the Soviet Union, the British command lost interest in the new tank guns. The generals decided that in the near future there will definitely not be major tank battles and 140-mm guns are not needed. In turn, in the course of possible military conflicts, the existing 120 caliber tank guns of millimeters will suffice. Work on the British 140-mm guns first slowed down and then stopped.
Germany, project NPzK-140
Unlike the British, German designers from Rheinmetall immediately took into account the possibility of installing a new gun on existing Leopard 2 tanks. At the same time, almost immediately after the start of the development of the new cannon, called NPzK-140, it became clear that this would require completely reworking the turret of the tank. This need was due to both the calculated dimensions of the gun itself, and the placement of the newly designed automatic loader. However, the creation of the new tower was postponed indefinitely: in Rheinmetall it was decided that it was first necessary to finish all the work on the cannon and only then make the tower so that it would not have to constantly make adjustments to its design.
At the final design stage, the NPzK-140 gun was a typical tank weapon, differing from the others only in caliber. At the same time, several original solutions were applied to its design. For example, to ensure compatibility with the most convenient version of the automatic loader, the gun was equipped with a bolt with a vertically falling wedge. Also had to significantly rework the ejector gun and equip it with new recoil devices. The last task was one of the most difficult. Due to twice the energy of the powder charge of a standard shot, the recoil increased significantly. But the chassis of the tank "Leopard-2", which in the future could be equipped with a new gun, was not adapted to such loads. Nevertheless, Rinmetall's constructive feeds eventually managed to reduce the calculated return to acceptable values.
Despite certain successes in the design, the new NPzK-140 140 gun never went into the series. At the beginning of the two thousand years, a test stand was made and six copies of the gun itself. Tests of these guns went with varying success, but in the end the project was closed. NPzK-140 in the current state was considered inconvenient and unfinished. Not wanting to spend money on fine-tuning the new weapon, the German military chose to refuse the order. Some developments on this project, primarily of a technological nature, were later used to create the Rh-120 LLR L / 47 tool.
France
American, German and British projects tank guns caliber 140 millimeters were the most successful and reached the stage of testing. In the remaining state party to the agreement on the FTMA program - France - things went a little worse. For example, the French company GIAT Industries, experiencing a number of technical and technological problems, eventually abandoned the creation of its own tool. Nevertheless, she took an active part in other projects and helped British and German enterprises. In recent years, rumors have been circulating about the resumption of the French project, which now has old goals: to create a new weapon for promising European tanks. Despite the available developments, full-fledged news about this project is unlikely to appear in the near future.
Outside of NATO
At the same time with the USA, Great Britain, Germany and France, other countries that are not part of the North Atlantic Alliance became interested in the issue of increasing the caliber of tank guns. The motivation was exactly the same: the increase in caliber promised a big increase in basic combat qualities, and this advantage more than covered all the concerns about the high cost of development and construction or technical problems associated with high energy of the shot.
Switzerland
Interestingly, Swiss engineers from Swiss Ordnance Enterprise (SOE) began developing their 140-mm gun a bit earlier than the NATO countries. Apparently, Switzerland was counting only on its own strength and, seeing foreign advances in this direction, decided to start a similar project too. The construction of the Swiss cannon began in the mid eighties. It should be noted that when developing a new tank gun, it was considered not as a full-fledged armament for promising and modern tanks, but as an experimental model for determining the appearance of a gun and developing new technologies. Nevertheless, even with such views, the possibility of mounting a new gun on Pz 87 Leo tanks (licensed by Leopard 2 of Swiss production) was taken into account.
There is evidence that the basis for the new tank gun caliber 140 millimeters was taken gun Rheinmetall Rh-120, which was originally recruited tanks "Leopard-2". For this reason, the main features of the appearance of the new gun resemble the original Rh-120. At the same time, several solutions were applied to reduce returns. A few years before the foreign projects of similar guns, the Swiss designers not only equipped their gun with new anti-recoil devices, but also used a muzzle brake. The latter consisted of several rows of holes near the muzzle. According to some sources, the efficiency of the muzzle brake exceeded 60%. In addition, due to the location of its holes at some distance from the muzzle, a more efficient use of powder gases was provided, because after passing through the holes of the brake, the projectile continued to receive energy from the gases for some time.
For the new gun, it was planned to create several types of separate-sleeve ammunition, but the main one was the armor-piercing subcaliber, for use with which the propelling charge was optimized. About ten kilograms of gunpowder were placed in a combustible sleeve. In addition, about five kilograms were attached directly to the projectile. Thus, the propellant charge was divided into two parts in a separate-sleeve ammunition. It was assumed that in cumulative or fragmentation shots only the charge placed in the sleeve would be used. Swiss-made ammunition had a serious difference from the shots described in the agreement between the NATO countries. Their sleeves had a smaller length and a larger diameter. According to the official data of the company SOE, in the future, if necessary, it would be possible to change the design of the cannon chamber and the shape of the sleeves for unification with NATO shells.
All technical solutions aimed at reducing the recoil impulse ultimately led to the possibility of mounting a new 140-mm cannon on the Leopard-2 tank. However, first the tests were carried out on a special stand. The new Swiss gun fired the 1988 of the year for the first time in the summer. At the same time, all the necessary data were collected and some modifications of its design were carried out. By the autumn of next year, an experimental vehicle with an updated turret and a new 87-mm gun was assembled on the basis of the serial tank Pz 140 Leo. During the firing at the stand and as part of the tank’s armament, the new gun showed more than interesting results. For example, from a distance of a kilometer, a sub-caliber projectile designed for it was pierced to a meter (!) Of homogeneous armor.
Despite successful tests, the new gun did not go into the series. The reason for this end of the project was the high cost and complexity of the gun, as well as the lack of prerequisites for its launch. In the early nineties, all European countries, due to the collapse of the USSR, reduced defense spending and the purchase of new weapons. The Swiss project 140-mm tank gun added to the list of closed as superfluous and expensive work. According to reports, over the next years, prototypes of guns were used in various test programs, but it was emphasized that this is a purely experimental weapon and Switzerland does not intend to use it for military purposes.
Ukraine, the gun "Bagira"
In the second half of the nineties, a country joined the creation of promising 140-millimeter cannons, from which they were unlikely to expect such work. The Kiev design bureau "Artillery armament" has developed a tank gun of increased power 55L "Bagheera". It is argued that this weapon can be installed on any tank of the latest models of Soviet, Russian or Ukrainian production and significantly improves its fighting qualities.
Available technical information about Bagheera is limited to a few numbers. It is known that with a barrel length of seven meters (50 caliber), the 55L can accelerate a seven kilogram sabot to speeds of the order of 1850-1870 meters per second. The declared armor penetration is up to 450 millimeters at a meeting angle of 60 degrees. Shooting distance was not specified. From the official data of the Design Bureau Artillery Armament, it can be concluded that at least two types of shots were created for the Bagheera. Perhaps firing armor-piercing subcaliber or high-explosive fragmentation shots of separate-cartridge loading.
Any information about the 55L “Bagheera” testing is missing. From the photos on the official website of the developer organization, it is possible to draw a conclusion regarding the manufacture and installation of an experimental gun on a test bench. Information about the purchase of tools also missing. Probably, over the past years, “Bagheera” has not interested potential buyers.
Caliber and expediency
As we see, all projects of tank guns of new-caliber 140 millimeters are faced with the same problems. First of all, this is a super-efficient payoff, which could not be fully compensated with the use of old practices. Of course, in the practice of tank building, more serious calibers with corresponding returns were used, but all the new tools were intended to modernize the existing equipment, which was simply not calculated for such loads. Technical features of a larger-caliber gun entail a number of consequences, such as the need for more robust construction details of the entire tank, a more powerful engine, etc. Ultimately, all this affects the price of the finished tank.
The second controversial point of the 140-mm tank gun concept concerns its tactical features. On the one hand, such weapons have significantly higher armor penetration characteristics in comparison with the usual 120- and 125-mm guns. At the same time, it is not possible to fit the bulk combat with 140-millimeter shots into the dimensions of a modern tank. This will lead to a reduction in ammunition and the corresponding tactical consequences. Confronting the power of the gun and the number of portable shots is the subject of a separate dispute.
In general, 140 caliber tank guns of millimeters, like many other types of weapons, have both pros and cons. In the current conditions, when the development of tanks is not as intense as in previous decades, the use of new calibers looks like an unreasonable measure. It seems that the military of the leading countries will prefer to remain with sufficient and mastered 120 and 125 caliber millimeters, while more serious systems will remain a sign of self-propelled artillery installations.
On the materials of the sites:
http://army-guide.com/
http://globalsecurity.org/
http://defense-update.com/
http://btvt.narod.ru/
http://arrows.newmail.ru/
http://vadimvswar.narod.ru/
http://articles.janes.com/
http://rheinmetall-defence.com/
http://kbao.com.ua/
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