High Caliber Projects Discussion and Implementation

High Caliber Projects
Work in progress
This post is created using publicly available information.
This post will only consist of prototypes, I may consider doing mock-ups in the future, but for now I want to get prototypes, testbeds and technology demonstrators done.
Some vehicles may have more information listed for them due to availability.
If anyone has any information that isn’t already posted, let me know and I’ll be sure to update the post with it, Credit will be given. Please AVOID posting classified information.
Discussion for High Caliber Tank projects and potential introduction into War Thunder

United States

In 1993, the US Army successfully concluded the ambitious ATD project, focused on evaluating cutting-edge defense advancements. The core concept of this initiative was conducting tests on prototypes manufactured according to standardized production methods, transforming them into genuine “weapons of the future.”

The CATTB, aptly named, is an extensively altered Abrams tank testbed that served as a platform for evaluating cutting-edge technologies. Among its notable features were a 140mm cannon with an autoloader, a state-of-the-art turbocharged 1450hp diesel engine, and an advanced suite of electronics. The research program for Block III Abrams, of which the CATTB played a significant role, was unfortunately halted following the collapse of the Soviet Union due to significant budgetary limitations.

XM964 next to M829 APFSDS
Specifications - Thanks to @Unknown_Memory_1 for the additional information.

  • Mass: 70 tons
  • Length: 26ft
  • Width: 12ft
  • Height: 8ft
  • Crew: 3
  • Armor: Ceramic Inserts (The CATTB’s hull armor is 945Lbs heavier than the M1A1 hull armor, 4,060 lbs for the CATTB and 3,115 lbs for the standard M1A1 hull armor.)
    • Hull Protection against APFSDS: 513-550mm in the middle and 590-620mm in the fuel tanks area.
    • Hull protection against Chemical: 890mm in the middle and 1050-1125 in the fuel tanks area
    • Turret Protection against APFSDS: Roughly 1020-1090mm for the turret front cheeks. 470-480mm on the turret sides.
    • Turret Protection against Chemical: Roughly 1650-1800mm for the turret front cheeks. 800-850mm on the turret sides.
  • Main Armament: 140 mm XM291 (39 rounds) (17 rounds in the turret bustle and 22 in the hull.)
    Megajoules: 18
    • APFSDS-T: XM964
      Maximum Penetration: 900-1000mm
      Estimated in-game penetration: Placeholder
      Muzzle Velocity: 1675 m/s
    • HEAT-MP-T: XM965 (to use against Helicopters.)
      Muzzle Velocity: 1050m/s
  • Smoke Grenade Launchers: 80 x 66mm
  • Engine: 1450-horsepower Cummins turbodiesel
  • Transmission: Allison DDA X-1100-3B
    Maximum Speed: Paved surfaces 67km/h, Rough terrain 40km/h





The final chapter in the CATTB history unfolded during the 1990s with the introduction of the “Thumper” Abrams, a simplified variant of the CATTB developed by Lockheed Martin. The Thumper model, however, omitted several costly advanced systems and was equipped solely with the 120mm version of the XM291 gun, rendering the transition to the 140mm caliber impractical. Although the tank’s weight was reduced compared to the CATTB, its armor levels only matched those of the M1A2 variant. The Thumper underwent testing alongside the XM8 (the initial one), but unfortunately, it met the same fate and was also eventually canceled. It’s essential to clarify these details because the Thumper and the CATTB are often confused despite being distinct vehicles.

M1 Abrams XM291
The ATAC gun was affixed to the typical M1 Abrams turret, gaining recognition primarily for being featured on the CATTB.


Rheinmetall, under a BWB (Federal Office of Defense Technology and Procurement) contract, has manufactured six prototypes of a 140mm smoothbore gun along with its corresponding APFSDS-T ammunition, specifically for trial purposes.

more information needed
The KWS III program was conceived as the third phase of the Leopard 2 tanks modernization initiative. KWS I involved upgrading the L44 120 mm cannon to a 55-caliber model, while KWS II resulted in the Leopard 2A5 modernization. KWS III aimed to develop a new turret with a 140 mm smoothbore weapon system and an automatic loader, reducing the crew size to three soldiers.
In the final design, the main gun was moved to the left turret side, and a lateral loading mechanism was incorporated. The main gun had an ammunition load of 32 rounds, stored in a large ammunition bunker at the turret rear. This relocation of ammunition from the crew’s compartment increased survivability in case of penetration. The intended protection level was on par with or better than the Leopard 2A5. Additionally, the tank’s command and control were set to improve through the implementation of the latest version of the ISIS system.
Despite the promising features, the KWS III program was not adopted at the time. Nevertheless, development of the 140 mm weapon system continued with Rheinmetall collaborating with Royal Ordnance from the UK and GIAT from France. To assess the weapon’s capabilities, the 140 mm gun was mounted on a Leopard 2 tank. This experimental tank lacked the new turret armor and automatic loader planned for the KWS III program and still utilized an electro-hydraulic turret drive. To handle the added weight of the main gun, counterweights were added to the turret rear. The tests yielded partial success, demonstrating the gun’s superior penetration power but also revealing some handling difficulties.

KF51 Panther
The unveiling of Russia’s T-14 Armata tank underscored the outdated status of German tanks. Consequently, the Ministry of Defense has urged the development of a Leopard successor, anticipated by 2030. Ongoing enhancements to the Leopard, presently at version 2A7(V), have led to the emergence of the MBT Revolution. As the Leopard design is gradually phased out and competition intensifies, a fresh line of contemporary armor systems, including the speculated KF51 Panther, has been under development since 2014/2015, with a potential unveiling at Eurosatory 2022.

Thanks to @eleks12 and @WreckingAres283 for making suggestions, I will link them below.


eleks12’s suggestion
KF51 Panther
WreckingAres283’s suggestion
KF51 Panther (HERO 120) - The New Apex Predator


  • Mass: 59t (65 short tons; 58 long tons)
  • Length: 25ft
  • Width: 12ft
  • Height: 8ft
  • Crew: 3–4
    • Commander (turret)
    • Gunner (turret)
    • Driver (hull)
    • Additional crew member (hull)
      (Each workstation can hand over and take over tasks and roles from others with no reduction of functionality)
  • Armor: A lot is unknown about this vehicles armor but the turret armor is suspected to be better armored than that of the Leopard 2A7 and the Hull is nearly identical to the Leopard 2A4.
  • Active Protection System: StrikeShield and AMAP-ADS
  • Main Armament: Rh-130 L/52 (up to 20 ready rounds)
  • Secondary Armament: 12.7mm coaxial machine gun (250 ready rounds), 7.62 mm NATTER RCWS (2,500 rounds)
  • Special Armament: HERO 120 Loitering Munitions (Optional)
    Rate of Fire: 6 seconds
    Megajoules: 18-20
    • APFSDS: more information needed
      Maximum Penetration: 1150mm-1200mm
      Estimated in-game penetration: 850~
      Muzzle Velocity: 1,800-1950
    • High-explosive: HEMP (Multipurpose High Explosive)
      Muzzle Velocity: more information needed
  • Engine: MTU MB 873 Ka-501 V-12 water-cooled diesel
  • Transmission: Renk HSWL 354
  • Suspension: Torsion bar
    Maximum Speed: 72km/h~
  • Other: Placeholder




KF-51 Eurosatory 2024

Soviet Union
The USSR developed a wide variety of 152mm guns for future MBT projects, here is a list.

  1. LP-81 gun, created by CNII Burevesting, project name Buntar, used in Object 477 Bokser/Molot

  2. LP-83 gun, created by CNII Burevesting, project name Taran, ammo project name Zaraysk, used in Object 477A Molot and Object 292.

  3. 2A73 gun, created by OKB-9 Uralmash, used in Object 477A1 Nota

  4. 2A83 gun, created by OKB-9 Uralmash, ammo project name Grifel, presumably also used on the T-72-based testbed with 2A83 in a small unmanned turret.

During the mid-20th century, the advancement of tank weaponry reached its zenith in terms of calibers. Both domestically and internationally, various tank models were introduced, armed with 152mm caliber guns. Efforts were made to mount more potent weapons on tracked armored vehicles with turrets, but these attempts proved unsuccessful. In fact, by the 1960s, military officials and tank manufacturers came to the realization that even 152mm or 155mm guns were excessive for modern tanks. As a result, contemporary tank designs shifted towards equipping vehicles with 120mm or 125mm guns, which were deemed more appropriate for their requirements.

Object 292 Implemented
T-80B Testbed
Object 292 was a Soviet experimental tank built in September 1990, based on the T-80s chassis, using a new turret, and was armed with a 152.4 mm rifled gun. In September 1990 the tank was completed and in 1991 underwent trials.


  • Length: 24ft
  • Width: 11ft
  • Height: 7ft
  • Armor: rolled and cast steel and combined, protivosnaryadny
  • Main Armament: LP-83 152.4
    Rate of Fire: 6 Rounds a minute
    Megajoules: 20-25
    • APFSDS: Zaraysk APFSDS (Allegedly it can also fire Grifel-1 and Grifel-2, but this isn’t confirmed, sources claim that Grifel series of ammunition belonged to the 2A83 gun on the Object 195)
      Maximum Penetration: 1,000~
      Estimated in-game penetration: 800
      Muzzle Velocity: 1980m/s
    • High-explosive: Grifel-3? (Not confirmed)
      Muzzle Velocity: 920m/s
  • Engine: GTD-1250
    Maximum Speed: 73km/h



Object 477
Object 477 ‘Molot’, alternatively known as “Boxer” or FST-2, initiated its development as a next-generation MBT (Main Battle Tank) with an unmanned turret in 1981. The draft design was concluded in 1984, followed by the technical design in 1985, and the first prototype (mock-up) was constructed in 1987. Subsequently, some vehicles were handed over to Russia, where trials continued throughout the 1990s.
The tank features the Argus sight, which integrates LLTV (Low-Light Television) and imaging infrared channels, while a radar system is positioned atop the turret. The tank’s crew is seated in the hull. Its primary armament consists of a 152mm gun with an autoloader, boasting an impressive rate of fire of 14 shots per minute. The basic loading module can accommodate 10 rounds, which can be supplemented by two additional 12-round modules.
It is well-documented that work in Kharkov persisted for a period with funding from Russia. However, a subsequent decision was made to shift focus entirely to the Nizhny Tagil Object 195.

molot1 (1)molot2

Object 195
The Russian fourth-generation main battle tank, known as Object 195 or T-95, was developed by Uralvagonzavod in 1988 with the intention of complementing and gradually replacing the older T-80 and T-90 main battle tanks.
The Object 195 featured a design that marked a significant departure from the Soviet-era tanks currently in service, placing a greater emphasis on crew safety and protection.
One notable feature was its new adaptive hydropneumatic suspension, which drew similarities to that used by the MBT-70 and the Japanese Type 74 and Type 90 tanks.
The tank’s entire crew was to be housed within a sealed armored compartment located inside the hull, providing isolation from other tank components.
Its armament included the 152mm 2A83 smoothbore gun, equipped with an autoloader and utilizing single-piece ammunition featuring a longer and more powerful APFSDS penetrator capable of reaching velocities up to 2000m/s. Additionally, the tank was equipped with a 30mm co-axial autocannon.
Be sure to check out @eleks12 suggestion for the Object 195 / T-95 - The Armata’s Big Predecessor


  • Length: 26ft
  • Width: 12ft
  • Height: 11ft
  • Armor: Combinated, Welded, Rolled Steel
    • Hull Protection against APFSDS: 950mm~
    • Hull Protection against HEAT: 1500+mm
  • Active Protection Systems
    • Hard kill: Shtandart
    • Soft kill: Shtora-2
  • Reactive Armor: Kontakt-5
  • Main Armament: 152mm 2A83
    Rate of Fire: 10 Rounds a minute
    Megajoules 25
    • APFSDS: Grifel-1(Tungsten core), Grifel-2 (Depleted Uranium core)
      Maximum Penetration: (1024 at 2000m or 2km)
      Estimated in-game penetration: 860mm
      Muzzle Velocity: 1980-2000m/s
    • High-explosive: Grifel-3 (HE-FRAG)
      Muzzle Velocity: 950m/s
    • Tactical Nuclear Shell: 3BV3 (1 Kiloton of TNT equivalent)
      Muzzle Velocity: ?
    • ATGM: Sprinter (Tandem HEAT warhead)
  • Secondary armament: 30mm 2A42
    • Belt: 3UBR11
  • Other: Thermal Imager, Laser Rangefinder and Radar to detect and lock ground targets.
  • Suspention: Active hydropneumatics suspension
Estimated in-game penetration with Grifel-1

Thanks to @Alan_Tovarishch for this.




T-72 2A83 testbed





Centurion 140mm testbed
The British took a minimalist approach by mounting a 140mm gun on a turretless Centurion hull and conducted tests with the gun alone, as evident in this image. However, it’s important to note that in all instances, the adoption of the 140mm gun never materialized.

Challenger 2 Rheinmetall 130mm Gun Technology Demonstrator
Unveiled on July 31, 2020, the Rheinmetall Defence 130mm Gun Testbed Challenger 2 showcases a new turret featuring classified armor and a potent 130mm L/51 cannon equipped with an autoloader. Functioning as a testbed, it illustrates the Challenger 2’s capability to accommodate the 130mm gun, with an anticipated crew of three – a driver, gunner, and commander. Specifics regarding the classified armor and engine details are undisclosed. If adopted, this upgrade has the potential to significantly boost the Challenger 2’s prowess, presenting a substantial challenge to the Russian T-14 Armata tank.


Leclerc T4
“Prototype with an elongated turret built in 1996. It was armed with a 140 mm smoothbore gun designed by the arsenal of Bourges (EFAB). In order to avoid being scrapped, the prototype turret has been restored in the 2010s and mounted on a former Leclerc hull which was used in its last years as a towing vehicle. Following its restoration, the tank has been nicknamed Terminateur (Terminator) by the director of the technical section of the French Army (Section Technique de l’Armée de Terre or STAT) that made everything to preserve this technological demonstrator. In 2017, the Terminateur was presented with the experimental Scorpion camouflage.” - source
t4 t4ammo

EMBT Ascalon 140




Very little is known about China’s high caliber project, however a image exists showing what is a supposedly a WZ1001 fitted with 140mm gun - more information
ztz99 140
If anyone has any more publicly available information please feel free to share it or correct me, thank you.


In response to the potential threat posed by the latest generation of Soviet Main Battle Tanks (MBTs), Switzerland, as a non-NATO member, initiated an independent development program in the late 1980s to create a 140mm cannon. The development of this weapon was undertaken by RUAG, and in 1989, a single Panzer 87 was upgraded with this new cannon, resulting in a variant known as the Panzer 87-140.
Panzer 87-140
Panzer 87-140

Specification - Thanks to CaID for the sources listed in his suggestion.

  • Length: 31ft
  • Width: 12ft
  • Height: 8ft
  • Armor: Composite
    • Frontal Hull Protection against APFSDS: 350mm
    • Frontal Hull Protection against Chemical: 600mm
    • Frontal Turret Cheek protection against APFSDS: 800mm
    • Frontal Turret Cheek protection against Chemical: 820mm
  • Crew: 4
  • Main Armament: RUAG 140mm L/47 gun (32 rounds)
    Megajoules: 20-21
    • APFSDS: Pfeil Pat Lsp (DM53)
      Maximum Penetration: 805-1000mm (former is most likely though)
      Muzzle Velocity: 1800m/s
    • HEAT-FS: HL Pat MZ Lsp
      Muzzle Velocity: 1410m/s
  • Secondary armament: 7.5 mm MG 51/87(4,750 rounds)
  • Engine: MTU MB 873 Ka-501 liquid-cooled V12 twin-turbo diesel engine
  • Transmission: Renk HSWL 354
    Maximum Speed: 70 km/h

Thanks to @WreckingAres283 for the image.


Tomorrow I will write an article about the CATTB and about the Thumper with correct information. The NPzk-140 photo is not real according to MILTECH.

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This is probably why almost no information is exists on it, my mistake if true. I’ll continue to look into it.

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Swiss Panzer 87-140WE




I’m planning on adding this one, along with the Panzer 68 with a 140mm.

Swedish Strv-2000 T140/40 Unfinished Prototype.

Stridsvagn 2000 T140/40 - Tank Encyclopedia (tanks-encyclopedia.com)

Challenger 2 140 wooden mockup.
Armored Warfare on Twitter: “The British were amongst the countries trying in the 1980s to adopt a 140mm gun. On the image - a Challenger 2 mockup with a turret intended to house such a gun. #ArmoredWarfare #TankswithAW https://t.co/ZIa6QyT5wl” / X

Chieftain 140mm testbed.


I will get around to these in a little bit, thank you.

Maybe those vehicle would be testbed for Object 292 as there are another ‘Object 292’ paper plan.


just a carrying vehicle to and fro, that’s all - not a proposed vehicle at all. just means of moving the gun for testing

still, a 120 gun, the front of the armour has been removed in a wedge shape, the recuperators from a 140 added and the 120 fitted the vehicle was known as the ‘offset gun’ - still know the guys who built this

CATTB | Download Free PDF | Force | Solid there’s a ton of information here on the cattb. Including a mention of a spall liner

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Updated some of the ammunition sections and added another U.S. prototype with the ATAC gun.
EDIT: I also added the T-72 2A83 testbed and a list of the different 152mm guns developed by the USSR under the Soviet Union header. Images added for Switzerland. Maximum Penetration performances added, also engine and transmissions, still wip.

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Since 292 is here, it seems like a great time to mention about M1 CATTB and other high-caliber good looking beauties 🤤

Additional pics of M1 CATTB, 140mm, autoloading beast

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I’m struggling to find any information on the French Leclerc T4, does anyone have any sources?

Added statistics and brief history for the KF51 Panther. Still unfinished, some information may change.
Added brief history and new header image for the Challenger 2 Rheinmetall 130mm Gun Technology Demonstrator, statistics will appear eventually.

Panther Kf-51 firepower is based on the 130mm L52 gun (vertical movement: -9 o to +20 o) fully digital tower guidance system, stabilization system and tower operation backup system. According to Rheinmetall the Panther Kf-51 gun is 50% more effective than the 120mm guns in service at longer ranges. It can fire new kinetic energy, high-explosive, and Air Burst munitions. Comes with fully automatic 20 round ammo loading/management system (an additional 10 ammo is outside the loading system). According to Rheinmetall the automatic ammunition loading/management system achieves a minimum loading time of 4 seconds and a feeding time of 2 seconds, while the optimal time between two shots is 3 seconds.

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I have further information and estimation on high caliber APFSDS for western tanks.

Firstly a secondary source (Armed Forces International Journal, February 1987). Among the several figures claimed there for protection or penetration estimated for various tanks and ammunition, theres the “XM946” identified there as a 120mm APFSDS.

Given the context of the overall article and time period, I think this is a case of misidentification for the 140mm APFSDS XM964. The confusion is plausible when the same gun can fire 120mm rounds. In any case, “900mm” for XM964 is plausible given the dimention limits of the projectile (its not that much bigger than 120mm ammunition). While dimensions of the projectile can be estimated from pictures (mostly projectile width), velocity and length can be dialed up and down to get to the stated 900mm of penetration.

Regarding Rheinmetall´s 130mm caliber so far we´ve only seen a mockup that looks a lot like an upscaled 120mm DM53. Its even more likelier that the actual first real APFSDS in this caliber will be based on DM83, which is a projectile we haven´t even seen yet (but I suspect its going to be in the 850mm ballpark of penetration). This said, I´ve estimated an upscaled DM53 to 130mm with the best velocity possible and here are the results:
usando referencia base de 685 penetrator on DM53

980mm of penetration assuming 1950m/s (basically this is almost the maximum possible velocity for APFSDS using traditional explosive propellants, me personally I would assume a velocity a little bit lower, perhaps 1800m/s, which would produce 920mm of penetration)
I repeat, 130mm “DM13” most likely WILL NOT be based on DM53 so this is just an excersize in creativity, validating a potential penetration of high 900s mm. An even bigger projectile (length limit of whole rounds for calibers considered for MGCS is 1300mm) is more than possible so theres a lot of growth potential left.

Lastly, Nexter´s 140mm “Ascalon”. This caliber is competing against Rh130 and intended to fullfil the same requirements in terms of volume and performance. However the concepts published by Nexter show a radically new APFSDS with much higher L-D ratio (nowadays 30:1 is the norm). A secondary source states that muzzle velocity is somewhere between 1700-1800 m/s and likely its very similar to what the 130mm is required in order to hit reliably moving targets out to 4-5km.

As for the penetrator´s dimensions we are looking at something like this:
Penetrator length
penetrator width

As for penetration, this projectile (934x24mm) at 1800 m/s penetrates 1050mm and at 1700 m/s, 995mm. This is pretty much equal to the Grifel 152mm APFSDS at both high and low estimations.


From what source does this speed come?

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It’s a rough estimate from different sources, however it very well could probably reach speeds up to 1,800m/s. Perhaps I’ll gather my sources and list them under each vehicle in the future.