140mm smoothbore gun

[Foo Fighter]

The Iraqi units were hardly peer adversaries. When resupply is more risky and less guaranteed things will look different.

 

[muttbutt]

https://twitter.com/x/status/1527717317961990144

 

[Kat Tsun]

The Iraqi units were hardly peer adversaries.

Yes. That's why I mentioned it. The fact that they aren't killing M1s increases the ammunition burdens on individual US tanks.

If you aren't running out of ammo at 73 Easting you simply are never going to. You, or your enemy, will be dead long before that, and ammunition not fired is ammunition wasted.

Something of a tangent but the only times in Vietnam where tanks ran out of main gun ammo without being destroyed first were times where the tank was literally not threatened at all, and stuck around for reasons beyond actual utility for several hours. I'm thinking specifically of an incident in VN where a rifle company was fighting against NLF partisans and would have "broke and ran" according to the company commander, so he ordered a pair of M48s to "tough it out" and they sat around for like four hours being hit by pot shots from 14.5mms and .30 cal bursts instead of retreating to reload their ammo bins. Neither tank was injured and the crews were fine, just really annoyed.

Incidents like that led to a doubling of the coaxial ammo storage in the M1 tank explicitly.

When resupply is more risky and less guaranteed things will look different.

Not really, at least not as far as main gun rounds are concerned, although fuel and food are absolutely critical.

The problem with tanks is that the proportions of extant tanks, like M1, onboard ammunitions are informed by Vietnam or Korean experience. Lots of coaxial ammo, perhaps "enough" or close to it, and roughly twice as much main gun ammo, and roughly half to a third as much heavy machine gun ammo. This is a bad proportion because it results in tanks with large amounts of unused main gun rounds.

Tanks need to use fuel constantly, though, even if it's an APU to keep the battery charged. If I wanted to disable or degrade a tank platoon or company through siege tactics, I'd be mining the resupply routes/MSRs used by fuel convoys (or simply identify the fuel trucks and hit them individually) and wait for them to run out of gas in "literally about 20-30 hours", subsequently abandon their positions or at least unhorse, and attack them as light infantry.

This works, as the current Eastern European war shows, and will likely continue to work. Tankers aren't terribly good light infantry.

However if the tank has a manual backup system, like crank handles and physical switches that don't need power, and the crews have individual NODS or some means of passive night observation, it will still be a tough fight. Designing tanks to fight without regular fuel supplies is a pretty prescient idea, since ammo is a durable item. It's only really wasted if you die with shots to spare or run out of the ammo you're using, but no one seemed to use more than maybe 20 rounds a major engagement even in Desert Storm.

Also during Desert Storm, a particularly noteworthy ambush occurred where T-72 (or a Type 59, I'm not sure which) fought in this manner, as the tank commander realized that his battalion were being spotted from long range by thermal scopes, so he kept himself under armor, kept his tank off, and engaged two M1s using manual backup cranks and optical sights as they moved through his battalion. He knocked out two tanks (mobility kills, IIRC) and was subsequently killed when his tank was hit by counterfire.

I don't think we necessarily disagree on principle, just on the particulars of what classes of supply are important, TBH. Modern tank crews have run out of fuel, food, and machine gun rounds long before they've run out of main gun rounds, since modern tanks don't consume a lot of main gun rounds. They just don't miss their targets anymore. There's no point to carrying enough ammo for a single tank to knock out a battalion, but knocking out a company plus some whiffed shots is fine. Which means less 40-50 main gun rounds and more like 15-20.

Bigger fuel tanks (doubled fuel storage if possible, or more fuel efficient APUs for operation for extended periods (~48-72 hours) in a hide), fewer main gun rounds, more heavy machine gun ammo (2,000 or 3,000 rounds), and at minimum 10,000 rounds of coaxial ammunition (preferably all in a single bin and ready to go) are a few of the things a future MBT crew would like based on recent (past 30 years) history.

This might change in the future but there's no reason to believe that tanks are going to start needing to consume more main gun ammo.

 

[MadRat]

Seems like you could pack 20 pop-up missiles with much more potential in the same space, without needing a loader. Integrate some liquid-fuel powered drones to dispense as scouts upon command and you never need to roll over a hill to engage an enemy.

 

[shin_getter]

Ammo requirements really depends on the tactical situation. An MBT is a general purpose vehicle and can find itself used in many tactical situations.

In a tank fight, ammo requirements would not be high unless it is a tactically inferior attacking force trying to force success via sheer mass of numbers: aka Golan Heights or some of the worst executed Soviet attacks in ww2. Some suspect the same would happen in ww3, and given what we see with modern Russian performance the expectation was not unfounded. Modern nations is not staring down tens of thousands of tanks with good survivability against ATGMs so requirements change.

The vast majority of main gun ammo consumption was high explosives, to the point that US commanders sent 75mm Shermans as opposed to 76mm due to superior HE ammo resulting in the whole post war deathtrap story. Even the tank destroyer branch fired vastly more HE ammo than AP. Looking at recent urban warfare campaigns, a stupid amount of HE gets consumed as the aftermath clearly shows. There was a talk on siege of marawi where the standard tactics is placing a 105mm HE into every room in the targeted structure before infantry assault and consolidation, and there are Russia media videos of Syrian tankers just shooting every suspected structure with HE. In the urban warfare context, retreat and rearm is not too difficult and the siege of marawi had fires provided by manhandling mountain guns (Philippine didn't have tanks for this battle) into direct fire positions. As such a small ammo load wouldn't be a big problem.

A very large HV gun does induce other problems however. The protection of ammo is a serious problem as turret pop-tarts show. There is problem with gun elevation and depression. The muzzle blast effects interferes with infantry support.

In a era where tank's passive protection is in question, specialization is likely the answer. Armor is kind of all or nothing, and if existing configuration doesn't result in sufficient protection, it makes sense to give up firepower and mobility for meaningful protection, or just give up defending against category of threats altogether. A smaller gun means more protection at no loss in the performance of the primary mission of infantry support.

The anti-tank mission can be accomplished in many ways without involving a very large, very high velocity gun. Something like 120mm gun mortar with networked MRSI with guided ammo can defeat even very capable opponent tanks while still accomplishing infantry fire support mission, even better now that it has elevation to hit rooftops and ability to indirect fire. The high velocity gun is advantageous in short range engagements, where indirect fire and missiles are too clumsy, but sensors, communication and engagement ranges all are increasing while tanks aren't getting more stealthy or mobile to enable close combat better.

Anti-tank beats tanks, tanks beats some other stuff. Not much point getting tanks to beat tanks, that is like asking helicopters to counter opponent helicopters as opposed to using air superiority or ground based air defense. Mixed formation instead of omni-purpose vehicles when the technology makes the latter inefficient.

Also during Desert Storm, a particularly noteworthy ambush occurred where T-72 (or a Type 59, I'm not sure which) fought in this manner, as the tank commander realized that his battalion were being spotted from long range by thermal scopes, so he kept himself under armor, kept his tank off, and engaged two M1s using manual backup cranks and optical sights as they moved through his battalion. He knocked out two tanks (mobility kills, IIRC) and was subsequently killed when his tank was hit by counterfire.

An ATGM team with up to date tech can do this without all the problems of building and moving 50 ton vehicles into the battle area.

Tank is inferior at ambush unless missiles don't work.

 

[Foo Fighter]

The Iraqi units were hardly peer adversaries.

Yes. That's why I mentioned it. The fact that they aren't killing M1s increases the ammunition burdens on individual US tanks.

If you aren't running out of ammo at 73 Easting you simply are never going to. You, or your enemy, will be dead long before that, and ammunition not fired is ammunition wasted.

Something of a tangent but the only times in Vietnam where tanks ran out of main gun ammo without being destroyed first were times where the tank was literally not threatened at all, and stuck around for reasons beyond actual utility for several hours. I'm thinking specifically of an incident in VN where a rifle company was fighting against NLF partisans and would have "broke and ran" according to the company commander, so he ordered a pair of M48s to "tough it out" and they sat around for like four hours being hit by pot shots from 14.5mms and .30 cal bursts instead of retreating to reload their ammo bins. Neither tank was injured and the crews were fine, just really annoyed.

Incidents like that led to a doubling of the coaxial ammo storage in the M1 tank explicitly.

When resupply is more risky and less guaranteed things will look different.

Not really, at least not as far as main gun rounds are concerned, although fuel and food are absolutely critical.

The problem with tanks is that the proportions of extant tanks, like M1, onboard ammunitions are informed by Vietnam or Korean experience. Lots of coaxial ammo, perhaps "enough" or close to it, and roughly twice as much main gun ammo, and roughly half to a third as much heavy machine gun ammo. This is a bad proportion because it results in tanks with large amounts of unused main gun rounds.

Tanks need to use fuel constantly, though, even if it's an APU to keep the battery charged. If I wanted to disable or degrade a tank platoon or company through siege tactics, I'd be mining the resupply routes/MSRs used by fuel convoys (or simply identify the fuel trucks and hit them individually) and wait for them to run out of gas in "literally about 20-30 hours", subsequently abandon their positions or at least unhorse, and attack them as light infantry.

This works, as the current Eastern European war shows, and will likely continue to work. Tankers aren't terribly good light infantry.

However if the tank has a manual backup system, like crank handles and physical switches that don't need power, and the crews have individual NODS or some means of passive night observation, it will still be a tough fight. Designing tanks to fight without regular fuel supplies is a pretty prescient idea, since ammo is a durable item. It's only really wasted if you die with shots to spare or run out of the ammo you're using, but no one seemed to use more than maybe 20 rounds a major engagement even in Desert Storm.

Also during Desert Storm, a particularly noteworthy ambush occurred where T-72 (or a Type 59, I'm not sure which) fought in this manner, as the tank commander realized that his battalion were being spotted from long range by thermal scopes, so he kept himself under armor, kept his tank off, and engaged two M1s using manual backup cranks and optical sights as they moved through his battalion. He knocked out two tanks (mobility kills, IIRC) and was subsequently killed when his tank was hit by counterfire.

I don't think we necessarily disagree on principle, just on the particulars of what classes of supply are important, TBH. Modern tank crews have run out of fuel, food, and machine gun rounds long before they've run out of main gun rounds, since modern tanks don't consume a lot of main gun rounds. They just don't miss their targets anymore. There's no point to carrying enough ammo for a single tank to knock out a battalion, but knocking out a company plus some whiffed shots is fine. Which means less 40-50 main gun rounds and more like 15-20.

Bigger fuel tanks (doubled fuel storage if possible, or more fuel efficient APUs for operation for extended periods (~48-72 hours) in a hide), fewer main gun rounds, more heavy machine gun ammo (2,000 or 3,000 rounds), and at minimum 10,000 rounds of coaxial ammunition (preferably all in a single bin and ready to go) are a few of the things a future MBT crew would like based on recent (past 30 years) history.

This might change in the future but there's no reason to believe that tanks are going to start needing to consume more main gun ammo.

I have had to do a hard reset, something I knew but did not really appreciate and that makes me feel stoopid.

Progress, moving forwards and while this progress is not linear, it is still apparent but knowing it does not mean accepting it as doctrine. Something that I failed to do was to 'appreciate' progress' properly.

You see, I am a remnant of an analogue world where .5 BRG was the Norm (Sorry City Slickers) and the laser range finder we had needed a second logic button due to returning a range of about 2' when we KNEW we were firing to at least dot 1 (1100M) due to lasing a raindrop.

Seriously though, show me a rank gunner who has enough ammo and I'll point out that he is the tank driver. Bombing up, never the most popular passtime for some reason. Probably all the packing that gets in the way.

You raised some good and simple points I thought I had allowed for but did not. Must not make that error again.

 

[Kat Tsun]

Funny you mention machine gun ranging, since the M1 battlesight is around 1,500 meters, because the coax and the sabot rounds hit the same point at that range. With modern laser warning receivers and automatic slewing becoming a thing, rangefinders are pretty dangerous to use, so Joes are taught to lase things next to a tank target and just guess. Maybe machine gun ranging will come back.

Everything old is new again, eventually.

I guess if tankers, being notorious packrats of weapons and munitions, really need the extra ammo, perhaps some sort of bulletproof/splinterproof armored box can be devised. If tank turrets like OMT are really going to be uninhabited and armored against 80% threats (12.7-30mm) instead of 100% threats (T-72), then there might be enough clear space on the turret to put spare rounds of machine gun or main gun rounds on top.

Being bulletproof and splinter proof means they won't be hurt aside from a main gun round or anti-tank grenade, so the tank can fire <ammunition nature> to depletion and retreat to reload, while another tank in the platoon goes on line and fights while they reload.

I imagine a robotic/uninhabited turret could potentially ease the ammo loading burden too, since you can probably devise an automatic loader with such limited protection to be loaded externally, negating the need to move rounds around inside the cramped turret like the T-64's notorious loading procedure. Just open the bin and throw 'em into the little pistol port on the back and the autoloader scans the new round (maybe a QR code etched on the case stub?) and indexes for a new shell.

The boxes would just be empty and filled with modular racks that could be pulled out (like the ready racks on an M1's bustle) and hold ammo cans of .50 or .30 cal, or individual 120mm shells, and I suppose if you really need to protect your robot turret, like engaging in close urban/Bocage terrain, you can replace the ammo boxes with Special Armor boxes instead.

It won't slake the ammo thirst but it would at least alleviate ammo concerns by keeping spare rounds protected against the most common threats (splinter and heavy machine guns) and out of the fighting compartment entirely.

 

[MadRat]

They've explored all sorts of solutions for storing rounds. If you stored in a perfectly safe solution for the crew, it creates a complex mechanism that will have too many failure points. Add in a larger caliber and the challenges only get to a higher hurdle. There is no perfect solution. Current western solutions are a compromise. They are practical solutions to compromises. Russian tanks are stuck in the mud when it comes to progress. When in doubt do the same as it ever was.

If I was trying to automate the process I'd stick to an unmanned turret. It would use a central column running to the floor of the tank. The floor in this case would be raised in the vicinity of the turret, to house an ammunition magazine and spares compartment underneath. The turret should be able to be run in an emergency with backup power sources, such as a handcrank for rotating the turret. Its going to need a way to reload (cycle rounds) in cases of engine failure, too. Cycling rounds and resupply is unlikely to use a handcrank, so a backup battery pack is the logical solution. The column is likely going to resemble something off a naval ship. On the plus side, it could be weatherproof and completely submersible.

Reloading would be done externally from the top of the turret. Ammunition would cycle into the box and be sorted by type. (Might be a good moment in time to rethink shapes of rounds to maximize utility in an autoloader.). The compartment should be protected from IEDs but also be able to blow out without killing the crew. Ceramics and aerogels can create superior resistance to cooked off ammunition in the event of blowouts. Yes, some thought needs to go into the design so that the crew doesn't get cooked.

 

[Colonial-Marine]

So is this ASCALON a descendant of the various NATO 140mm smoothbore gun or is it an entirely new development?

 

[TomS]

So is this ASCALON a descendant of the various NATO 140mm smoothbore gun or is it an entirely new development?

It supposedly incorporates some lessons from the NATO 140mm but it's essentially new. It's a single-piece fully telescoped round, because they've developed extremely long/thin penetrators that don't work with two-piece separate loading ammo.

Nexter prepares the future of battle tank armament | Nexter

Leaning on its expertise in battle tank armament, illustrated by the Leclerc's self-loading gun, and on the excellence of its ammunition activity, Nexter (KNDS group) is presenting a new main armament concept for main battle tanks, designed to deal with future heavily armoured threats.

www.nexter-group.fr

 

[Moose]

I wonder what the non-sabot rounds they're looking at. While the drive to 130/140mm is about killing tanks, they're still likely to be spending a lot of time shooting at not-tanks.

 

[TomS]

I wonder what the non-sabot rounds they're looking at. While the drive to 130/140mm is about killing tanks, they're still likely to be spending a lot of time shooting at not-tanks.

Rheinmetall has mentioned an HE-ABM round (more like a 3P programmable fuze that can airburst, impact, or delay). Basically a scaled DM11.

EUROSATORY 2016 - Rheinmetall (External Pe6b, Stand D261-211) is presenting its latest 130mm smoothbore tank gun.

O mundo militar em um so lugar: Orbis Defense!!!

orbisdefense.blogspot.com

Nexter apparently has shown a 140mm guided Non-line-of-sight (NLOS) projectile. No word on unguided HE though.

DSEI 2021 : de nouvelles munitions Nexter pour les chars d'aujourd'hui et de demain - FOB - Forces Operations Blog

Plusieurs projets de munitions de char étaient présentés pour la première fois par Nexter lors du salon DSEI, organisé cette semaine à Londres. L'une, de calibre 140 mm, s'oriente vers le char de demain. Les deux autres, de calibre 120 mm, entendent donner du mordant aux plateformes actuelles.

www.forcesoperations.com

 

[MadRat]

Getting too many types of shells into the tank seems like it would over-complicate manual loading and unloading. Wouldn't specialized shells be better from modern self-propelled guns?

 

[Kat Tsun]

Getting too many types of shells into the tank seems like it would over-complicate manual loading and unloading. Wouldn't specialized shells be better from modern self-propelled guns?

"Manual loading"? 105mm had like four or five major natures (HEAT, sabot, smoke, HEP, canister) back in the day and nothing bothered them. A modern autoloader would be even less trouble since it would just index based on the datalink in the case stub. That's what CT40 does and what M829A4 and AMP have capacity for.

Besides that, two natures of ammunition (explosive and sabot) has been the standard for years for most militaries.

 

[GTX]

I think this image (also shown on previous page of this thread) comparing a 140mm round to a 120mm one should end any thoughts re manual loading:

 

[Sovngard]

140mm ETC was part of initial plans. One common parameter was a common breech size of 20 cubic liters.

Source ?

 

[Bruno Anthony]

140mm ETC was part of initial plans. One common parameter was a common breech size of 20 cubic liters.

Source ?

https://www.secretprojects.co.uk/attachments/a875bd17-392d-4d33-accd-446246235e12-png.677774/

 

[Bruno Anthony]

140mm ETC was part of initial plans. One common parameter was a common breech size of 20 cubic liters.

Source ?

As for the common 20 liter chamber it might be here
Post in thread 'US Army's 1990s AMS Program (FIFV, Block III Tank, Crusader)'
https://www.secretprojects.co.uk/th...fifv-block-iii-tank-crusader.3860/post-233790

or here

https://twitter.com/x/status/1516058844404895747

View: https://twitter.com/iannicholsonip/status/1516058844404895747?s=21&t=_0DMVNSVMDJz9xfMA7xGFA

 

[muttbutt]

Vid of it firing

https://twitter.com/x/status/1541819769724325888

 

[Sovngard]

Article on ASCALON : https://lasd.online/140-ascalon/

 

[jsport]

Video Game art

CATTB

The CATTB is a Tier 10 special premium Main Battle Tank under Sophie Wölfli's dealership. Class: Main Battle Tank (Prototype) Developed: 1987-1988 Service: N/A Vehicles Built: 1 Operators: N/A The CATTB is, as its name suggests, a heavily modified Abrams tank testbed used as a platform for...

armoredwarfare.fandom.com

Qbicle art 'CATTB Vanguard'

140mm ATACS (ETC) Smoothbore Cannon with Fastdraw Autoloader

 

[MadRat]

120mm was already a leap in raw kinetic energy over the 105mm. This looks like a greater than doubling of the kinetic energy at 120mm's maximum range. Imagine how much gain there is while in much closer ranges. I hope there is a guided round involved to assure first lead on the head.

 

[asVAL]

are a few weird testbeds that look at a few kludged breadboards like VIDS.

Pardon my bumping, but what is/was the VIDS? I can make out Vehicle, Demonstrator System, but what is the I for?

 

[Bruno Anthony]

are a few weird testbeds that look at a few kludged breadboards like VIDS.

Pardon my bumping, but what is/was the VIDS? I can make out Vehicle, Demonstrator System, but what is the I for?

Vehicle Integrated Defense System.
Tank protection system based on sensors, countermeasure, and slewing turret around to return fire at detected threat.

 

[scrubhead]

If anyone can read Chinese, would you please translate what this says? More Xm-291 120 and 140mm info. Found this in a comment section on Reddit about a leaked Chinese "140mm" APFSDS rod compared to a 125mm rod. I don't know the source and crediblity is unknown, might just be Chinese guess work on the Xm-291 or entirely made up, if not, big find.


Also heres the the """"leaked"""" "140mm" Apfsds rod comparison


Heres the original post:

https://www.reddit.com/r/TankPorn/comments/16e368l

View: https://www.reddit.com/r/TankPorn/comments/16e368l/leaked_photo_of_a_140mm_chinese_apfsds_next_to_a/

 

[scrubhead]

Searched a bit more. Apparently both images originate from the War Thunder forums. The original post for both images ( 13th post ) was posted on August 22nd. The green rod is DTW-125. The length of DTW-125 round is 642 mm. Apparently the black rod really is from a 140. I really thought it was a LRP from the longer 125mm one piece ammo gun from a few years back since it looked too short.

The estimated length of the 140mm round from the WT forums is apparently only 850mm. Surprisingly and disappointingly short. From the forum as well, is three pages from a document called GJB 3659-99 Caliber series for gun of armoured vehicles created in 1999 posted in reply to the 13th post. It lists a 140mm gun. The figure with data for Rh120, Xm-291 and Chinese 140mm is apparently from a Chinese essay written in 1998 according to the one who posted it and the 140mm rod ( the 13th post ). This means the information on Xm-291 is either guess work or legit information. There is possibly more info on it and the Chinese 140mm program if we could find or get the full Essay. According to the same poster, the Chinese 140mm started development in and around 1990-1995 or "as soon as ZPT-98 finished development".

War thunder forum thread:

China Norinco VT series MBTs, History, Performance & Discussion

Also worth noting that GJB 3659-99 Caliber series for gun of armoured vehicles also lists a 140mm tank gun… and this document was created in 1999. <details><summary>Spoiler</summary></details>

forum.warthunder.com

Of course, this is still WT forums so take this with a grain of salt.



GJB 3659-99 Caliber series for gun of armoured vehicles in spoiler. A translation of these pages would also be appreciated.

Spoiler

 

[Scott Kenny]

120mm was already a leap in raw kinetic energy over the 105mm. This looks like a greater than doubling of the kinetic energy at 120mm's maximum range. Imagine how much gain there is while in much closer ranges. I hope there is a guided round involved to assure first lead on the head.

Long rods don't lose all that much velocity over range, IIRC the 120mm rod is still doing about 1350m/s at 1500m (starting at 1500m/s). The 140mm would lose less energy per distance, but IIRC all the energy numbers I saw were roughly double that of the 120mm.

 

[MadRat]

I believe with penetrating rods it is rigidity that is the magic sauce. As simple as it sounds, as pressure climbs it is more difficult to hold a perfect linear form. Weight, velocity, air friction, and rotation all have to be in harmony or the rod deforms and doesn't strike at the correct angle. I don't know the forces involved but its a knife's edge to get it all correct from what I hear.

 

[Nik]

"...it is more difficult to hold a perfect linear form."

Ick...
Thank you for explaining that so lucidly.

Sounds like modern equivalent to the 'Archers Paradox', where high speed photography reveals how much a long arrow wriggles and flexes during launch...

And, tangential, some of the many issues plaguing prop aircraft with mid/buried engines and too-long drive-shafts...

( OT: Also, those 'unfortunate' ships, with some 'engine revs' deprecated due to resonance. Hmm, which was the {in}famous liner that lost a lot of 3rd-class / steerage volume to essential, urgent retrofit with massive bracing to prevent stern shaking loose and falling off ?? )

 

[Scott Kenny]

"...it is more difficult to hold a perfect linear form."

Ick...
Thank you for explaining that so lucidly.

Sounds like modern equivalent to the 'Archers Paradox', where high speed photography reveals how much a long arrow wriggles and flexes during launch...

Modern long-rods have an advantage, as they're being pulled down the barrel rather than pushed from the back like an arrow.

And, tangential, some of the many issues plaguing prop aircraft with mid/buried engines and too-long drive-shafts...

Cars, too. Interestingly, the 1990s Taurus SHO with the 200hp Yamaha V6 used driveshafts of two different diameters/thicknesses to address the torque steer problem. So despite the two very different length driveshafts, they had the same twist resistance.