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Tank Guns

Thanks anti body your realli good with such stuff kindly aslo if possible post comparrission of tank guns in asia as a whole and origins countries thanks again mate

you're welcome! I've just enumerated some guns at the moment

well if If i get some time I will try to enumerate some chinese tank guns with some data links -- it's upto the members where they want to take the discussion after that ... however please do post links as you can see i've tried to find links in most of the cases

before making it a 'vs' thread let the junior TTs etc first collect data ... no fruit in discussing without data
Problems Encountered with Higher Caliber Tank Guns

According to estimations from the mid-80s, the future soviet tank (FST-3) had enough armor to defeat anti-tank ammunition fired from a current 120mm powder gun. Future NATO tank guns would have to produce 18MJ worth of energy at the muzzle, for the penetrator of an armor piercing fin-stabilized discarding sabot (APFSDS) – double the energy produced by the Rheinmetall 120mm L/44 gun mounted on the Leopard 2 and M1A1 Abrams (produced in the United States as the M256).1 A number of solutions were proposed, including the use of a 140mm solid propellant gun. There were a number of more extravagant solutions, including electromagnetic acceleration and electrothermal-chemical ignition and control. Despite the wide array of options in regards to enhancing vehicle lethality, the easiest and fastest solution remains the adoption of a 140mm powder (solid propellant) tank gun. In fact, most tank-producing nations have developed a number of 140mm cannons for use in future tanks and 140mm guns have been fitted into existing turrets; however, no nation has seriously considered the use of a 140mm gun. Since the late 70s tank enthusiasts have been predicting the introduction of larger caliber weapons. Yet, no Israeli Merkava tank has been seen with a 140mm tank gun2 and no Russian tank has been seriously developed with a 152mm piece.3 On the other hand, development continues with electrothermal-chemical technology for use in tank guns, and some still see electromagnetic propulsion as the future in tank armament.

Nevertheless, calibers larger than 120mm are still enticing and see extensive use in NationStates. Especially popular are either the 152mm or 155mm calibers. The use of both these calibers has been popular ever since the publication of multiple articles giving estimations on the armament of the Black Eagle – a T-80U turret upgrade – and the future T-95.4 It should be noted that the Black Eagle turret mounts a solid propellant 125mm tank gun, probably the 2A46M-4 tank gun adopted on the T-80UE.5 The T-95s armament, admittedly, remains a mystery, along with the rest of the tank. There have been actual attempts to mount a larger caliber tank gun into existing tank turrets, although very few details are published about these projects. The Swiss mounted a NATO 140mm gun into a Panzer 876 and the Russians have recently introduced a long 152mm cannon into a T-80, with some turret extensions in the front and a bustle in the rear. It’s possible that there have been prototypes of a 140mm armed main battle tank in the United States of America, although the main battle tank program was canceled in 1995


A Newsweek article with concept art of the FST-2

The lack of information on the development and testing of tank guns of a caliber between 130mm and 160mm admittedly makes it difficult to understand the consequences of implementing a gun of this caliber. These negative side effects of increasing lethality through increasing caliber only accumulate as the caliber gets larger – i.e. the effects of using a 155mm gun are much greater than those of using a 140mm gun. Consequently, oftentimes the use of these heavy cannons in tank designs in NationStates doesn’t accurately portray the negative side effects. Although this isn’t necessarily the author’s fault, it’s a mistake that should be corrected. This informative is an attempt to explain the advantages, as well as the various disadvantages, of larger caliber tank armaments. These disadvantages include increased turret volume, potential increase in hull volume and increase in weight. The informative’s argument is that these increases in volume and weight do not justify the increased lethality, especially given that there are many alternative options in tank gun technology.

140mm+ caliber lethality
The original goal, as stated above, was to achieve muzzle energy of 18MJ. In tank armor penetration by kinetic energy (armor piercing fin stabilized discarding sabot – APFSDS) the principle (and the simplest) factors which effect penetration are velocity and mass.8 Therefore, the simplest equation which can given an idea of a round’s penetration is KE = ½m •v2. With an increase in muzzle energy you can either increase mass or velocity of the round. With a decrease in mass there is an increase in velocity, and the same is true vice versa. This greater muzzle energy is established through the use of larger propellant charges – larger barrels can withstand larger charges because the created pressure during gas expansion is distributed along a greater surface area. The idea is the same in high-pressure guns, except that special materials are used to withstand higher pressure in the breech and barrel.9 Although the common goal is 18MJ, there is nothing that suggests that the muzzle energy produced by a 140mm caliber tank gun is and always will be 18MJ. The performance of a 140mm gun, and any gun, is based only upon the construction quality of the barrel, breech and round and the quality and volume of the propellant. In fact, a 140mm gun may produce only 16 or 17MJ of energy.10

According to Rheinmetall, a 140mm tank gun produces energy of 23MJ at the muzzle. However, only 14MJ are relevant to the penetrator itself.11 Fired from a NATO 140mm gun, a tungsten heavy alloy (WHA) penetrator with a length to diameter (L:d) ratio of will penetrate roughly 830mm of rolled homogenous steel after penetrating a 400mm ceramic module (the ceramic is not necessarily encased in steel).12 Due to the considerable power achieved by the 140mm powder gun and the availability of the technology, it was thought as early as 1989 that the 140mm would be used as a stop-gap solution.13 The amount of technology demonstrators of this caliber make it apparent that at one point in time it was a real solution. The U.S. XM291 solid propellant gun showcased a breech which could fit both a long 120mm cannon and a 140mm cannon if it was necessary in the future.14 However, today the 140mm gun is no longer considered a real option by any NATO tank-producing country.15 Instead, the Germans introduced the new 55-caliber long 120mm tube and the DM53 APFSDS in the KWS I upgrade of the Leopard 2A5 (the 2A4 to 2A5 upgrade is the KWS II, which increases the depth of the front armor array).16 The XM291 120mm tube is also longer than the current M256 (a copy of the Rheinmetall 120mm L/44), but was never implemented and there is still no gun modernization program in sight


British advanced tank armament mounted on a Centurion chassis.

Although the 140mm tank gun, and any caliber above 120mm, offers better ballistics than existing 120mm solid propellant guns against current and future armored threats, the large-caliber gun was a solution based on the lack of time.19 Prior to the fall of the Soviet Union the FST-2 and FST-3 were considered threats beyond the capabilities of NATO tanks of that time, including the M1A1 and Leopard 2. The M1A1HA (heavy armor) upgrade was introduced at a cost of around $1 billion due to the threat posed by the theoretical FST-2.20 Beginning in 1988, there were 1,328 M1A1HA tanks manufactured and another 834 with increased armor protection (M1A!HA+).21 However, the Soviet Union fell in 1991 without producing either the FST-2 or the FST-3. Thankfully, the fall of the Soviet Union has allowed us to take a closer look at the advantages of a 140mm gun. The pace of development has decreased, along with decreased budgets for research and design work on advanced tank armaments. Instead, work has been put into upgrading the lethality of light armored fighting vehicles for deployment in peace keeping operations. This has given Western nations a chance to develop next-generation armaments in the 120mm caliber. However, if NATO wants to design a future tank with MLC 60 or 50 as its weight limit, tank designers will have to look for a smaller caliber solution.

Even with a decrease in the ammunition held, the volume of thirty 140mm rounds would be roughly 3.05m3. An individual 140mm APFSDS could weigh as high as 40kg, while a 120mm APFSDS weighs between 19 and 23k. This means that thirty 140mm rounds would weigh roughly 1,200kg as compared to the 830kg of a forty round 120mm ammunition load. 22 Rheinmetall’s 120mm L/44 weighs 1,190kg, while the L/55 version increases the weight to 1,347kg. GIAT’s (now Nexter) 120mm F1 weighs 2,800kg and the M256 weighs 1,901kg. The high-pressure MG251 weighs roughly 3,300kg.23 However, let’s take Rheinmetall’s L/55 and the XM291 as the more recent in solid propellant technology (the XM291 saves about 600kg worth of weigh as compared to the M256). In comparison, a 140mm gun (including the trunnions) would weigh over 3,200kg. It would also require a breaking force of up to 1,200KN.24 In gun weight and ammunition weight alone the increase in weigh would be about 1.5 metric tons. The necessary increase in turret volume to allow a depression of the main gun to anywhere between 7º and 10º could cost another 5 to 6 metric tones in weight. The increase in gun caliber would also result in an increase in the size of the mantlet, resulting in another increase in armor volume and weight. In fact, a total weight increase due to the larger turret armor volume could amount to up to over 10 metric tons.25 Insofar, the total weight increase amounts to closer to 15 metric tones. Taking the weight of the Leopard 2E of around 63,000kg26, it would mean that based on what we have figured out a 140mm tank with the same proportions of mobility, protection and lethality would weigh almost 78,000kg. In order to keep within the maximum acceptable ground pressure of 9N/cm2 the chassis would also have to be enlarged in both width and length. The increase in weight of a 140mm gun, with a proportional increase in protection and mobility, would be a far greater difference to existing main battle tanks than is the difference between the M60 (52,000kg27) and the M1A2 (roughly 64,000 to 65,000kg28).

The maximum width of the vehicle is dictated by what is allowed by a nation’s rail system. The amounts of distance between any given points in the majority of nations in NationStates make travel by tank track improbable. NATO armies, and their allies, have always used rails, while the Soviets have always had the philosophy that a tank should be prepared to travel great distances on its own tracks. But, the Soviets have traded other aspects of their tanks for increased engine life. In terms of track life, the AMX-30’s tracks could travel an average of 5,000km. 29 Track life of current tracks is most likely similar, as no major innovations with track durability have really been made. Fuel considerations make travel by truck over long distances as improbable as travel by one’s own track. Currently, Spain’s truck transport can fit a single Leopard 2E or two Pizarro infantry combat vehicles. Assuming that a truck was made to carry a much larger main battle tank it would still only be able to carry one. Taking into consideration tank fleets in NationStates, let alone distance to travel, the amount of trucks required to transport armor material across the country would exceed a country’s capability. The width of a nation’s highway lane also plays apart in the allowable width of a tank. The use of multi-lane highways solves the problem to a certain degree, but doesn’t get rid of it. The costs of constructing a multi-lane highway network across a country the size of the Soviet Union would not allow a nation to procure an expensive main battle tank! On a more serious note, it’s not realistic to assume that a nation can change the width of its railroad tracks to accommodate a larger main battle tank. Therefore, there exists a physical limit on the width of any main battle tank.

Battlefield mobility of a tank is dictated by the relationship between the length of the track touching the ground and the width between the centerlines of each track. Ratios of over 1.5 will disallow a tank from making quick turns, and may even cause a crew to damage or break the tank’s transmission. Given the maximum allowable gun pressure we know that there is a maximum allowable weight per width. Width is hard to increase due to road and rail constraints. Consequently, one could say that there is a maximum weight limit of a tank. Taking into consideration Western rail gauge, this limit seems to be MLC 70 (roughly 64,000kg). Therefore, a 78,000kg tank would find it hard to strategically deploy long distances, not to mention the ability to deploy overseas!

Even so, 78,000kg doesn’t take into consideration several more weight augmentations. An increased weight requires increased engine volume and fuel volume. Fuel tanks, within themselves, constitute a substantial increase in weight due to protection requirements. It would be nearly impossible for a human loader to load 40kg ammunition in the ideal loading time of 5 to 7 seconds, and therefore an automatic loader would be necessary. Nevertheless, the weight of the ammunition would require a loading system of at least 600kg, so there are no weight savings in that area. And, we are assuming an armor protection equal to current tanks. Ideally, a 140mm armed tank would also have an increase in armor protection. That constitutes a large increase in weight. 35 metric tons of the Abram’s weight is armor,30 meaning we’re looking at a weight increase of armor by a factor of at least ten metric tons. In terms of aerial density armor protection can weigh up to 4 metric tones per meter.31 Therefore, if current lethality and protection patterns are kept the 140mm armed tank could weigh well over 80,000kg.


A comparison chart, offered by Rheinmetall, with three different Rheinmetall tank armaments.

Taking weight into consideration, one should also figure in logistics. The cost of logistics can be related to as the eighth power of the tank’s weight (for a tank of the weight we’re discussing).32 Therefore, the logistics slice of a 80 ton tank would be roughly 5 times greater than an existing 63 ton tank! And this fails to mention the cost of construction of each individual tank. The cost considerations in manpower, man hours and logistics resources are exponentially greater than those in a modern real-life main battle tank. The use of advanced technologies, such as computerized active hydropneumatic suspensions and computerized transmissions will add to the cost of the tank, but this fact remains the same in all tank design.

Unconventional Solutions
If weight is the principle cause of the problem, any user of a large caliber tank gun should look into solutions which reduce weight. Nominally, this means unconventional turret designs. As an example, Jordan’s King Abdullah Development and Design Bureau (Kaddb) revealed the new Falcon turret at Idex 2001. The turret is designed to reduce he frontal profile as much as possible (although, it should be known that the smaller the frontal profile of the turret, the larger the sides will be33), as well as weight, and is an upgrade option for Arab M60 Patton tanks and Jordan’s own Challengers (Al Husseins). The two man turret crew (the driver is still in the hull) is seated in the turret basket, reducing the required amount of protection in the front. By reducing the front turret profile and moving the position of the crew Kaddb radically decreased the armored volume of the turret reducing weight just as dramatically. However, moving the crew into the turret basket results in disallowing the tank commander from a good panoramic view – in essence, he’s commanding the tank based on computers. Furthermore, the Falcon turret’s autoloader only holds eleven rounds (with plans to increase to sixteen), compared to the forty rounds held by the M1 Abrams34 – the Falcon turret is wedded to Ruag’s 120mm compact tank gun (CTG), which weighs 2,600kg.35

Reducing turret volume, as shown by the Falcon turret upgrade, is always an option and may result in a hefty reduction of weight, given the reduction in armored value. As a reference, assuming full nuclear, biological and chemical (NBC) protection each crew member will require about .4m3 and the loader .8m3 to achieve the fastest loading rate possible (as close to 5 seconds as possible)36 and to this we add another 10% for crew comfort and freedom of movement. So we can come to the conclusion that a conventional four man crew requires just about 2.5m3 in terms of volume. This is even larger for tanks which attempt to move the driver into the turret, since that driver now needs to counter-rotate meaning his required volume will be based on the spine of his seat and not on his center of mass, effectively doubling the required volume. A three man crew, however, requires less than 2m3 plus the required volume for the tank autolading system. In terms of turret volume, however, we’re talking about a volume reduction of a little bit over 1m3. Jordan pays the price in the weight of its gun (heavier breech) and the relatively small ammunition hold, and the inability to replenish the autoloader’s ammunition under armor (instead, the crew has to replenish from the outside). One can also reduce the crew from four or three to two, reducing fighting compartment volume from 10m3 to around 3m3. 37 There are, as always, important considerations including the requirement to train multiple crews per tank – a two-man crew will not be able to successfully guard the tank at night, or maintain the tank on their own. Furthermore, each crew member now has a larger share of the tasks.38

Other turret options include the cleft turret and the externally mounted gun. The former reduces turret volume, and the latter almost gets rid of it completely (you only have to armor the breech against small arms). Both have huge ballistic weaknesses, although if you can guarantee the first-round and the necessary lethality of that first-round then ballistic weaknesses are almost irrelevant.

However, it’s questionable whether a 140mm solid propellant gun or even a 155mm solid propellant gun can penetrate the armor of a NationStates tank on the first hit. Let’s say that a M289A3 APFSDS scaled up to be fired from a 140mm gun (larger mass) has a penetration of roughly 1,200mm of RHAe (rolled homogenous armor equivalent); this is still insufficient to penetrate a large number of tanks with over 2,000mm RHAe along the front 60º arc. Always hitting the side armor is unlikely, as that’s what the Israelis did during the Six Day War yet close to 35% of the hits are registered to hit the tank front 60º. During the Yom Kippur War near 55% of the hits were registered on the front 60º and during the Second World War (the most ‘copied’ war of NationStates) this percentage increases up to the 70% mark! 39 This doesn’t even begin to take into consideration the armor protection between the 60º and 90º protection arc in main battle tanks, or up to the 120º degree arc! The Black Eagle, for example, has explosive reactive armor integrated into the front 120º arc of the turret.40 One source claims a turret armor protection of up to 880mm for the Black Eagle, although if an improvement in side turret front armor over the T-80U is assumed then we’re looking at more than 400mm worth of protection against kinetic energy (KE) threats in terms of conventional armor.41 If Kontakt-5 provides 300mm worth of equivalent armor against APFSDS,42 then it’s possible that the Black Eagle has a side turret front protection level of over 700mm RHAe, and possibly up to 800mm RHAe. That means that the Black Eagle may have a side turret front armor protection level close to the front protection level of current generation main battle tanks. Improvement in passive armor thickness and mass efficiency, as well as improvements in explosive reactive armor, might mean an even higher level of protection. Although the Black Eagle is not going to be adopted by the Russian Army, it serves as an example as what future tanks can achieve (like the T-95).


A comparison between the T-95 and the M1 Abrams in size.

For example, with a weight increase of just 1.5 to 2.5 metric tons43 the M1A2 SEP can adopt a heavy explosive reactive armor suite increasing protection by about 300mm RHAe. This would increase effective protection along the front 60º arc to over 1,200mm RHAe and the side turret front armor to about 650mm RHAe. 44 The most important consideration to take into consideration is that Kontakt-5 explosive reactive armor proved to completely stop the M289 APFSDS.45 Although the new M289A3 APFSD was specifically designed to defeat Russian explosive reactive armor, new reactive armor concepts may prove more difficult to puncture. For example, Ukraine’s Nozh explosive reactive armor uses a series of explosively formed penetrators to literally cut the APFSDS into several pieces. However, Nozh suffers from the disadvantage of relying on a dramatic impact angle. Regardless, the point remains that the efficiency of explosive reactive armor shouldn’t be measured in RHAe as opposed to its ability to break the incoming APFSDS.

This takes us back to turret design. If one can reduce armor volume to reduce weight, one can rearrange previous armor in order to increase the thickness of the surface area left. In other words, a tank with a narrow mantlet turret can have an increased thickness in armor for no penalty in weight (you just don’t lose the weight). So, if by maximizing line of sight thickness of the armor, like the Leopard 2A5, a future tank can achieve armor protection of around 1,500mm RHAe then a 140mm gun is incapable of penetrating the frontal arc of that tank. Of course, an electrothermal-chemical gun might be incapable as well, but it doesn’t have the added weight penalties!

Technological solutions
There are advances in tank technology which may allow for weight savings. The German MTU 880 series of diesel engines produce around 215kW/m3, a substantial improvement over prior diesels – it is 35% smaller in volume and 14% lighter in weight.46 In other words, the MTU 880 produces 288hp/m3, which means that to provide a hp/t ratio of at least 20:1 the engine bay would require at least 5.6m3 (based on a 80,000kg tank). This would produce 1,600hp, while a 2,000hp engine would require about another 2m3 worth of volume. MTU claims that the MTU 890 series engine is 50% smaller than the MTU 880 series in terms of volume47, which to me says that the MTU 890 can produce 430kW/m3, or that a 1,600hp engine bay would require a volume of about 2.8m3. There are claims that the MTU 890 produces 1.2MW/m3, 48 but these are highly suspect – nevertheless, the lack of an alternate source disallows me from discarding the figure. Nevertheless, use this latter figure as carefully as possible; else we might have another buckyball trend! Regardless, new diesel engines provide a heavy savings in weight, forgive the pun.

There are also weight savings in the areas of future transmission systems, and the use of certain materials in vehicle and armor construction.49 Alternate armor could be a consideration, or even the reduction of armor protection to save mobility. This concept was the guideline for the French AMX-3050 and the German Leopard 1,51 and may have been the guideline for the U.S. future main battle tank (FMBT) which aimed for a combat weight of 20 metric tons.52 Of course, the problem isn’t as severe as it is for a twenty ton tank with the goals of a sixty ton tank, but there are similarities. While technological breakthroughs may save some weight, any heavy NS tank design that scales up with current technology will have to rely more on ingenuity than on technology. Cost should also be taken into consideration when using high technology. Currently, more than 60% of a tank’s cost is the high technology and electronics used. 53 If a M1A2 costs $5.4 million to produce54 then $3.24 million is applied to electronics. That said, any future tank with the most advanced in terms of electronics and high technology to save weight or enhance features that now have to support greater weight may cost over $10 million. These systems include electric transmission, active hydropneumatic suspension and advanced remote controlled weapon stations. There’s also a high cost in the technology provided to manufacture certain parts of the future tank (like advanced armor).

There are great deals of alternatives to 140mm guns in smaller calibers which can be explored.55 This includes the more well known electrothermal-chemical technology, which will provide the necessary energy to match the muzzle energy of a 140mm gun. Unfortunately, this comes with the added costs. Technologies which may be applied to the future, assuming advances in energy storage and efficiencies, are electromagnetic propulsion systems – for example, rail guns and coil guns. However, these are not solutions to be considered for a long while. Simpler alternatives are improved solid propellant guns. The 120mm L/55 firing the DM63 can penetrate as much as 900mm of rolled homogenous steel, 56 while the penetration of the same gun firing the M289A3 may exceed 1,000mm of penetration! Advanced solid propellants might also offer short-term improvements in lethality, with smoother burn patterns and higher amounts of energy per volume. The alternatives are out there, they just require some researching!


Swiss Pz87 with a 140mm gun.

On the other hand, advances are in the form of the ammunition. Rounds like the XM943 can engage tanks at long ranges and defeat them by engaging the roof armor with an explosively formed penetrator57 – in other words, a gun-launched long-range anti-tank missile. Rounds like SADARM58 can drop multiple submunitions on a target, increasing chances of penetration. This type of guided ammunition greatly increases the engagement ranges of tanks and questions the requirement of heavy armor. For example, a 155mm howitzer can knock out one or more tanks using submunitions while those tanks can’t even respond. The introduction of indirect fire munitions may merge the roles of heavy armor and self-propelled artillery, although the former could never provide the necessities for occupation (the lack of heavy protection) while the latter is simply too expensive to replace the artillery vehicle. Indirect fire munitions may also argue in support of large guns – the larger the gun, the larger the round the more submunitions it can hold. However, it also argues for the use of smaller caliber guns. A tank designed with a 105mm high velocity gun has superior mobility than larger variants, may have an equal level of protection and can engage enemy tanks at non-line of sight (NLOS) ranges. Its armor protection would be enough to protect it against infantry armaments such as light anti-tank rockets or top-attack missiles through the use of explosive reactive armor and an active protection system. It would also be cheaper and a nation could deploy more for the same costs.

In the end, the use of alternatives is up to the creator. There are always design specifications and operational requirements to take into consideration. Each creator might also have different opinions and perspectives. It’s all part of the game. However, it’s important to always take into consideration the advantages and disadvantages of any given piece of equipment – including large caliber tank guns.

Problems Encountered with Higher Caliber Tank Guns (Nsdraftroom)
Maximum Chamber pressure for different guns.

2A26 and early 2A46 5100 bars (T-72)
2A46M-1 and later models 6500 bars (T-90 and T80U)
British L30 6180 bars (Challanger-2)
Rheinmetall 120mm L44 and US M256 7100 bars (M1A2 and older Leo)
Rheinmetall 120mm L55 7600 bars (Leo 2A6)
Morozov KBA3 6374 bars (Ukrainian T-80UD)
Morozov KBM2 7060 bars (Ukrainian T-84 Oplot)
ARDE 120mm L52 8400 bars (Arjun)

Although some people claim L55 to be having Max Camper pressure of 9000 bars... making it the most powerful tank gun in service.

Promising 140-mm tank gun

Today, the vast majority of today's world of tanks used smooth-120 and 125-mm guns. The exceptions are Indian Arjun and British Challenger I and II, which are equipped with 120-mm rifled guns. The transition to the second half of the XX century in smoothbore guns could markedly increase the kinetic energy of the projectile, thereby improving penetration.

• This free miracles, as we know, does not happen, and the smooth-bore guns rifled inferior in accuracy and range target shooting. These features and give rise to the use of sophisticated modern tank fire control systems.

• In the near future increase the firepower of tanks will be as through improved artillery, and increase the power of weapons. The increase in the caliber of tank guns is not a prerequisite. Improved design tools is on the way to improve the quality of steel used for the manufacture of the barrel, in order to increase the gas pressure in the chamber and the barrel when fired. And also on ways to reduce the uneven heating backlash, moments, and other phenomena affecting the trunk and accuracy.

• In the future, we can expect an increase firepower MBT and through the use of large-caliber guns. Currently, the Swiss company RUAG of gunsmiths created smoothbore tank gun, 140-mm. Characteristics of the new tools is not fully known, but there is information that RUAG worked version of the installation tool in fighting compartment tank Leopard 2A4. The development in this field are in the U.S., where he developed smooth dvukalibernoe gun XM291 120/140 mm. Leads the development in this area and the Ukraine, where the instrument was created 55L "Bagheera".


Tank gun 2A75 (left) and 2A46M-5 (right). Cannon 2A46M-5 - the most modern Russian tank gun, 125-mm

• In Russia, most experts agree on the judgment to leave as a main tank gun artillery system caliber 125 mm, but with the length of the barrel and the ability to use armor-piercing projectiles with increased long-piercing core. You also created and tested larger caliber smoothbore gun.

• It should be understood that an increase in the caliber of tank guns to 140 mm leads to almost halve carried in tank ammunition. That is what is at present a major deterrent to the use of a large-caliber tank guns.

German 140-mm smoothbore gun of "Rheinmetall"

• Under contract with the Federal Office of arms supplies (VWV) German company "Rheinmetall" produced six prototype 140-mm smoothbore guns and ammunition series APFSDS-T (armor piercing tracer feathered with detachable leading parts) for testing.

• This development was conducted in the framework of the international program for the creation of the main gun of the tank of the future FTMA, which is implemented by the United Kingdom, France, Germany and the USA. New 140-mm gun received the designation NPz K-140. This instrument is equipped with a heat insulating cover, wedges vertically incident type extractor of smoke. The gun was designed to increase the firepower of the German main battle tank "Leopard 2" .


Tank guns production "Rheinmetall" 120mm with a barrel 44 and 55 gauge and 140-mm gun NPz K-140

• It is assumed that the installation of the tank 140-mm guns will require replacement of the tower, which would get the automatic loader for separate loading 140-mm ammunition. Made test stand, but in production, nor in weapons this gun yet.

Swiss 140-mm tank gun

• Work to build a new 140-mm tank gun began in Switzerland in the late 1980s of the XX century. The firm "Ordnance Enterprise" started a program that was intended to demonstrate the ability to use more powerful guns not only to modernize the standing armed with tanks "Leopard 2", but also as a fortress guns. As a new tool to be used to its integration and new ammunition available MBT with minimum cost and to verify the expected performance of new ammunition.

• The first test of a new ballistic 140-mm smoothbore gun in a real combat situation took place in the summer of 1988, and the first firing ammunition from a gun mounted on a tank "Leopard 2" , took place in autumn 1989. To the new gun was created separate loading ammunition, consisting of the main propellant charge, which is a steel base and combustible container (about 10 kg warhead) and the projectile kinetic action, plus an additional 5 kg warhead. Also created a multi-purpose missile (MR), which most likely will not require the use of additional charge.

• The kinetic projectiles have extended core, which is made of base metal, not from depleted uranium, which is employed in the U.S. Munitions and body with a plastic driving bands. At the same time, the first shot is a multipurpose shaped-charge projectile having a strong enough additional fragmentation


• Swiss Cumorah 140-mm gun is somewhat shorter than the layout adopted by NATO countries, while according to the "Ordnance Enterprise," this weapon and ammunition to it when necessary can be quickly adjusted to the current international standards on the bolt.

• The main efforts of Swiss engineers to create new weapons based on the analysis of external ballistics on the final trajectory ammunition Kinetic Energy having different structural characteristics (diameter, mass, length, speed) against a number of test objectives. Parallel to this, the impact of multi-purpose shells studied in static tests.

Tests showed that the new 140-mm ammunition in a position to penetrate steel armor thickness of up to 1000 mm, which is a significant increase in armor penetration when compared with in service with 120-mm projectiles.

• It should be noted that the Swiss 140-mm smoothbore gun is still only a test gun. And given the significant reduction in the threat of war in Europe since the beginning of its development in the foreseeable future it will not be put into operation.

Development of 140-mm guns in the UK

• Over the years, former British Defence R & D management (DRA) to work on the project 140-mm tank gun for future FTMA. At first it was planned to create tools that will be ready to be in force at the beginning of XXI century, but the collapse of the Soviet Union and the demise of the Warsaw Pact significantly slowed work on the program, and an instrument had been received in the industrial production.

• In the UK, implemented two programs: one funded by the Ministry of Defense, and manage DRA, the major work on it were made ​​from 1989 to 1992. The second program was initiated by "Royal Ordnance" and ran from 1989 to 1993.


MBT UK "Challenger 2" 140-mm gun has not got

• By early 1993, "Royal Ordnance" and DRA conducted firing their 140-mm shells at landfills country. The company "Royal Ordnance" spent about 120 rounds of ammunition APFSDS its 140-mm gun mounted on a test bench. This gun provides 40% increased armor penetration compared with 120 mm guns. 140-mm ammunition for the new guns were significantly heavier than the existing 120-mm shells were therefore made separate, consisting of two parts (projectile and charge), which charges a weapon with automatic loader.

• As it turned out, the installation of a new 140-mm gun with an autoloader for tanks "Challenger-2" or M-1A1/A2 Abrams was very costly. On the new French tank "Leclerc" in the recess of the turret was installed automatic loader, but the main gun of the tank remained 120-mm gun. It was assumed that the shells APFSDS, which were to be used in the tank of the future FTMA, will have a core of depleted uranium. Such weapons have better armor penetration, but at the same time have a high cost of production and can not be used in peacetime for environmental reasons.

140-mm gun prospective U.S. system ATAC

• In the U.S. system perspective smoothbore tank gun caliber 140-mm (ATAS) consists of a gun XM-291, XM automatic loader-91 and a family of new ammunition. It was assumed that this system will be the main weapon of the future MBT project "Block III», which is being developed for the U.S. Army.

• 140-mm gun XM-291 is a powder tank gun with a monolithic installation and rollback mechanism that leads fire munitions, consisting of 2 parts (projectile and charge). Muzzle energy of the gun 2 times greater than the energy of a standard 120-mm gun M-256, which are armed with tanks "Abrams" M1A2 . The gun has an extractor of smoke, heat insulating cover and 91 pounds lighter than the standard M-256 guns.


140-mm gun XM-291 based on the tank "Abrams"

• originality of the proposed system is that after replacing the barrel (it takes about an hour), the system can fire 120-mm solid conventional and future ammunition. The gun works in conjunction with the automatic loader XM-91, which is able to recognize the selected types of ammunition. The mechanism of transfer of ammunition created by "Lockheed Martin".

• In the niche turret contains 17 pieces of 120-mm or 140-mm rounds, ready for immediate use, an additional 22 140-mm round two-piece or 33 unitary warhead caliber 120 mm can be placed in the body of the tank. Using the automatic loader allows for the rate of fire at 8-12 rounds per minute.

• The family of ammunition for ATAC system is represented by three shells: shaped-charge projectile XM-965 projectile Kinetic Energy XM-964 and XM-training projectile 966. Each shot is made up of the charge and projectile. The charge is the same for all three rounds and consists of a detonator and the base of the truncated parts combustible side wall of fire and a propelling charge. When fired, the sleeve is burned, leaving only the base. Snap connection charge of ammunition allows you to remove the shell from the breech end of the barrel.

• The prototypes developed system ATAC tested in the land forces of the U.S., with a commercial scale 140-mm tank gun promising not performed.

Ukrainian 140-mm gun, "Bagheera"

• In Ukraine also were developing weapons caliber 140 mm. As a result of construction work came to light gun L55 "Bagheera", number 55 in the title indicates the length of the barrel in calibers. This gun is designed to upgrade existing weapons and advanced models of armored vehicles. An option for installing it on the T-84M "Hold", but realized he was not


MBT Ukrainian T-84 "Hold" too while the 140-mm gun has not got

Characteristics of the experimental tank gun L55 "Bagheera":
Calibre - 140 mm
Barrel Length - 7000 mm (55 gauge)
Most recoil length - 310 mm
Muzzle velocity - 1870 m / s
Kreshernoe pressure - 564 MPa
Muzzle energy - 15.74 MJ
Receiver weight BPS - 9 kg
Flight weight BPS - 7 kg.

Sources used:
Here's the indian one120 Millimetre MBT Arjun Armament System

A state-of-the-art weapon and ammunition system has been developed by the DRDO for the Main Battle Tank (MBT) Arjun by adopting novel design concepts and latest technological advancement at par with the industrially advanced countries. The system is capable of destroying modern heavy targets up to a range of 5000 m. All aspects leading to ergonomics, product reliability, maintenance, ease of operation, and futuristic performance enhancement have been incorporated in the design of the system.

The following indigenous technologies have been developed and established during the course of the system development.

Electro slag refined (ESR) steel for gun barrels

Partial length autofrettaging of gun barrels

High pressure packing rings for recoil system

Tungsten alloy penetrators

Fin stabilised kinetic energy shot

Special alloy steel obturating cups for cartridge cases

Semi-combustible cartridge case and primer

Armament System

Gun System

The 120 mm rifled gun for MBT Arjun is made of special steel produced by the latest ESR/Vacuum Arc Remelting process. This has enhanced the performance and fatigue life of the gun barrel. The gun barrel has been partially autofrettaged to a pressure of 800 MPa to achieve a proof pressure of the order of 612 MPa. This is the first indigenously developed gun capable of firing at such a high service pressure achieving muzzle velocity of 1650 m/s and above. Efficient fume extractor of the gun ensures that no toxic fumes are left in the crew compartment. The gun is fitted with FRP Thermal Insulating Jacket to obviate differential thermal effect, thereby enhancing the accuracy of the weapon system.

Recoil System

The Arjun recoil system is a compact, lightweight, short recoil hydro-spring type, capable of absorbing the thrust of high pressure and high velocity gun. The system consists of two hydro-spring buffers mounted diagonally to meet the stringent space requirement inside the fighting compartment. The innovative design of taper control rod gives uniform recoil and run-out, thereby enhancing the accuracy and life of the system and the high rate of fire. The high pressure and durable packing rings coupled with high surface-finish of mating components ensure longer life and high reliability. This is a sealed system, which requires practically no maintenance.

Ammunition System

Two types of ammunition, namely, Fin Stabilised Armour Piercing Discarding Sabot (FSAPDS) and High Explosive Squash Head (HESH) have been fully developed and productionised for MBT Arjun.

The complete round of Arjun ammunition system consists of a semi-combustible cartridge case with steel obturating cup, semi-combustible primer, propellant, additive liner for wear reduction of gun and FSAPDS shot/HESH shell. The semi-combustible cartridge case (SCCC) ammunition has the advantage of reduction of round and chamber length, weight of the round, ease of handling, higher muzzle velocity, higher rate of fire, longer barrel life, and logistics.

Steel Obturating Cup

The SCCC technology is being used in the contemporary tanks. Steel cup is a major component of SCCC technology used for indigenous development of the ammunition for the Arjun tank, and has been designed, developed and productionised by the DRDO for the first time in the country. This component provides effective obturation during firing of the ammunition.


FSAPDS is the primary antitank ammunition for Arjun. The complete FSAPDS round consists of semi-combustible cartridge case, semi-combustible primer with steel obturating cup, triple-base propellant, and wear-reducing additive liner. The sub-calibre kinetic energy projectile has a very high-density long rod tungsten alloy penetrator enclosed in a three-piece sabot segment and a tail unit for in-flight stability with tracer. The shot is machined to a very high degree of precision with best CNC machines and online inspection to achieve the high standard of accuracy. This hyper velocity ammunition can defeat all the modern targets at a range of 5000 m and above. The accuracy and consistency of the shot is of the order of 0.2 mil standard deviation.


High Explosive Squash Head (HESH) is the secondary ammunition for Arjun and is effective against a variety of soft targets, tanks, fortifications, etc. The complete HESH round consists of a semi-combustible cartridge case, primer with steel obturating cup, and a single-base propellant. The optimised explosive composition of HESH defeats rolled homogenous armour plate detaching a scab of about 9 kg mass moving with a velocity of 100 to 120 m/s. Besides the scabbing effect, blast and shock imparts a tremendous jolt to the enemy tank stripping off explosive reactive armour and incapacitating the crew severely, thereby affecting their fighting capabilities. The accuracy of the HESH is of the order of 0.25 mil standard deviation.

The gun/ammunition system has been fully optimised and integrated with the MBT Arjun, meeting the stringent GSQR for consistency, penetration, lethality and high rate of fire. The production in ordnance factories has been well established. Strict quality control measures in the production stage and the final inspection stage are being maintained by DGQA/SQAE to ensure highest standard of quality.

Ordnance &Ammunition Data

Ordnance Ammunition

Calibre 120 mm rifled Scab mass 9 kg
Breech type Vertical sliding breechblock Scab diameter 280 mm
Semiautomatic/hand operated Scab velocity 120 m/s
Firing mechanism Electrical
Ordnance length 6050 mm HESH/T 1A
Ordnance mass 2025 kg
Barrel life 500 EFC Type of ammunition Fixed SCCC
Muzzle velocity 735 m/s
Thermal Insulating Jacket (TIJ) Round length 996 mm
Round mass 22 kg
Material FRP Consistency 0.25 mil
No. of units 2 (front and rear)
Type Split type, hinged FSAPDS/T 1A

Recoil System Type of ammunition Fixed SCCC
Muzzle velocity 1650 m/s
Type Hydro spring taper rod type and above
No. of cylinders 2 Round length 940 mm
Normal recoil 350 mm Round mass 20 kg
Recoil fluid Oil mineral hydraulic buffer Consistency 0.20 mil
Mass of each buffer 90 kg
@ANTIBODY : I have always wondered if there was a possibility of converting the gun assembly from decommissioned tanks into light arty for troop support. Both India and pakistan have nearly thousands of tanks which will be decommissioned/mothballed soon which haventt seen any combat, (less wear on the barrel). Any comments
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@ANTIBODY : I have always wondered if there was a possibility of converting the gun assembly from decommissioned tanks into light arty for troop support. Both India and pakistan have nearly thousands of tanks which will be decommissioned/mothballed soon which haventt seen any combat, (less wear on the barrel). Any comments

From what I know, Pakistan doesn't have any APCs over 30+ tons, so i strongly doubt any of the M113 variants(Hamza?) can support a turret heavy enough or withstand the recoil of an MBT gun without tipping over :)

A few of them can be used to fortify stationary outposts in terror-infested areas.
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@ANTIBODY : I have always wondered if there was a possibility of converting the gun assembly from decommissioned tanks into light arty for troop support. Both India and pakistan have nearly thousands of tanks which will be decommissioned/mothballed soon which haventt seen any combat, (less wear on the barrel). Any comments

@fatman17 or @Xeric will be able to give first hand info in this regard
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@fatman17 or @Xeric, Is it possible to decouple the the Gun, swivel/traverse system and the loading mechanism from the turret and mount it onto a howtzer like rig, to in other words recycle obsolete tanks for bolstering up border posts??
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High Caliber Gun Images.

Object 195 with its 152 mm smoothbore gun.


Object 292 with its 130 mm smoothbore gun.[experimental tank]


Leopard 2A4 with its 140 mm smoothbore gun.


M1A1 with its 140 mm smoothbore gun.


ZTZ99 with its 140 mm smoothbore gun.

From what I know, Pakistan doesn't have any APCs over 30+ tons, so i strongly doubt any of the M113 variants(Hamza?) can support a turret heavy enough or withstand the recoil of an MBT gun without tipping over :)

A few of them can be used to fortify stationary outposts in terror-infested areas.

Well.... if you can put a 105mm on a 3x3 Cadillac Gage LAV or a 4x4 Piranha, you can also put it on a M113. If it were a 120mm, a stretched M113 - like the 18 ton MTVL - might take it. By comparison, the Russian 2s25 Sprut-D at 18 tons has a 125mm tank cannon.... see also the 25 ton Centauro B1 with 120mm turret.

CG LAV-600


2s25 Sprut SD

Centauro b1 120mm

Or, picture yourself a 6 roadwheel version of an XM103 with a 120mm cannon.


m113 with various 90mm turrets (besides those with 76mm M24, Saladin and Saracen turrets and 60mm hvms turret).

Cadillace cage / Cockerill 90mm

CMI turret


Cockerill LCTS90MP turret.

Undefined on FNSS 6wheel stretched chassis
M113 with 60mm HVMS turret

M113 with M24 turret (76mm)

M113 w. Saladin 76mm turret

M113 w. Scorpion 76mm turret

ACV-S with BMP/BMD-3 100mm/30mm turret
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