Leopard 2A7I vs RX-78-2 Gundam

[Stark]

Yeah. The 120mm is shown blowing turrets off tanks, knocking over tanks, being super effective at suppressing large areas, etc. It seems like a decent choice for a general-purpose weapon, and they have bazookas et al for heavier work. They just made a bad call because they didn't expect the Federation to go from zero mobile suits to awesome mobile suits (and some really lame prototypes) in six months.

I'm just not sure if the Gundam being basically immune to the Zaku machinegun is too meaningful, given that it's probably not comparable to a modern tank shell directly. Armour's an odd issue in Gundam stuff because they go from shooting guns at each other to shooting weapons that over penetrate almost everything, where armour obviously isn't as important as agility.

[Kuja]

With threads of this type, I'm interested why people generally pick the original Gundam as their example. Sure, it was a hero robit in 1979, but even by Gundam standards internally it's not very interesting. Most modern anime viewers or robit enthusasts might not even know anything about it or ever have seen it in action. I uncharitably think this is why its chosen, as a weak example of robits, when they could pit a tank (for instance) against a Delta Plus or Asshimar (ie suits designed for combat in atmosphere) and it'd be utterly hilarious because they're essentially aircraft.

I think it's mostly two reasons-

One, the original Gundam series took itself much more seriously than its later spinoffs. As such, by comparison it did a lot of worldbuilding, a lot of "SCIENCE!" and attempted to have some manner of semi-realistic scifi combat, that is stuff like mecha vs tanks, insurgents, etc. Despite being old as hell now it still had a pretty broad fanbase thanks to games on the PS and PS2 keeping the memory alive. As a result its kind of a pinata for people to take shots at the logic, structure, and fans, and it just feels more 'crunchy' for versus debates.

Two, although I haven't kept up with the Gundamverse lately, in the era of spinoffs like G Gundam and Wing got pretty gonzo. Wing Zero would fly over the tank in this debate and BUSTER RIFLE it while Heero Yiu mumbled something about how war is hell and a chorus of Japanese girls sang something about emotions in the background. Domon Kasshu would grab the thing and use it to hit another giant robot. Basically, Gundam got bigger, louder, more explodey, less interested in worldbuilding. So that stuff isn't the target like OYW era Gundamverse. The relative weakness of the OG Gundam is just kind of a side-effect.

[Simon_Jester]

Well there is the shield but there's lots more to it, because they can angle the shield obviously so its a sloped surface...

I know essentially nothing about Gundams, but if the shield is a serious thickness of armored material, capable of stopping credible antitank weapons, and if the Gundam itself is armored to roughly tank-scale... yeah, the shield will be effective. Even if it's penetrated by an antitank weapon, the resulting projectile/shaped charge/whatever will typically be in no shape to punch through yet another layer of armor. That's why spaced armor exists in real life, along with concepts like "decapping plates" and "skirt armor."

I don't think the "APDS for the win" approach Gunhead talks about would work well either against that, he's right there. Sabot rounds have a record of punching through lots of relatively soft, crumbly stuff (like sand dunes and apartment buildings) to knock out a tank on the other side, but I'm not sure whether they could penetrate a large slab of armored material, especially an angled one, without starting to tumble and breaking up.

So go giant robot kite shields, I guess?

[Stark]

One, the original Gundam series took itself much more seriously than its later spinoffs. As such, by comparison it did a lot of worldbuilding, a lot of "SCIENCE!" and attempted to have some manner of semi-realistic scifi combat, that is stuff like mecha vs tanks, insurgents, etc. Despite being old as hell now it still had a pretty broad fanbase thanks to games on the PS and PS2 keeping the memory alive. As a result its kind of a pinata for people to take shots at the logic, structure, and fans, and it just feels more 'crunchy' for versus debates.

The 'orginal Gundam series' includes stuff like Unicorn which has waaaaaay more interesting robots that have much more interesting capabilities than 'can fly' and 'giant gun'. Even Nu Gundam makes these kind of threads more interesting because of the direct application of Jedi powers. The RX-78-2 is a boring dinosaur, even by UC standards; not surprising, since it was the first mobile suit the Federation ever made.

But saying 'first generation 20m robot vs mach 10 tank made of carbon nanotubes with magic bullets' is still lame.

Saying stuff like 00 doesn't take itself seriously is pretty unfair; it's just as consistent as UC. It would of course make vs threads hilariously one-sided towards the robits by virtue of being almost literally invincible, and nobody who makes these threads wants that. They want 'hurf durf stupid robits'.\

Simon, it sometimes seems that some mobile suits don't have meaningful armour at all (ie can't stop common peer weapons) but have very strong shields instead. Given the emphasis on agility the shield is certainly more useful than the same mass of armour spread over the suit, but I think they use specific materials/manufacturing/active systems to make them as resilient as possible. The RX-78-2 wouldn't have that sort of thing though; I think its shield is made out of thicker armour.

[Gunhead]

Well there is the shield but there's lots more to it, because they can angle the shield obviously so its a sloped surface...

I know essentially nothing about Gundams, but if the shield is a serious thickness of armored material, capable of stopping credible antitank weapons, and if the Gundam itself is armored to roughly tank-scale... yeah, the shield will be effective. Even if it's penetrated by an antitank weapon, the resulting projectile/shaped charge/whatever will typically be in no shape to punch through yet another layer of armor. That's why spaced armor exists in real life, along with concepts like "decapping plates" and "skirt armor."

I don't think the "APDS for the win" approach Gunhead talks about would work well either against that, he's right there. Sabot rounds have a record of punching through lots of relatively soft, crumbly stuff (like sand dunes and apartment buildings) to knock out a tank on the other side, but I'm not sure whether they could penetrate a large slab of armored material, especially an angled one, without starting to tumble and breaking up.

So go giant robot kite shields, I guess?

Without knowing the thickness and material properties of the shield, this is pretty much guesswork. A shield carried by a robit would work great against any explosion based weapon but against solid penetrators... Yes, it would hamper performance but to what degree is the big question. I'd start with thickness. Because in tank armor today, thickness is important. Both HEAT jets and APDS rounds move so fast the sloping isn't going to make them glance off. Sloping armor is used to increase the effective thickness the projectile has to pass through which increases the time it can be subjected to forces in an attempt to break the apart the round / disrupt the jet.
All things considered, a robot's shield would act pretty much like the side skirts on a tank. I personally doubt the shield would be thick enough to decap an APDS round unless the angle of impact is extremely favorable to it. Might cause some wobble to the round too as the fins on the round would break off when going through the shield. Don't know if this would affect the penetration of the main robit armor in any meaningful way. The distance between the shield and the robot's body is pretty small so the round doesn't have a lot time to tumble.

-Gunhead

[Stark]

The shields are unlikely to be more then 500mm, and the less advanced ones are shown being chewed up by solid shells on occasion. Regular old suits are unlikely to be resistant to that sort of thing; of course the old suits use similar weapons that fire like machine guns...

[energiewende]

An infantryman with a missile would be a better choice than a tank. Essentially invisible against a highly visible target, and not encumbered with a slowly-training, limited elevation gun.

[Stark]

And that's relevant to the thread.... ???? In any case it's even more situational than the tank.

[Simon_Jester]

Yeah. The infantryman might be able to land a hit, but Gundams are so mobile that a dismounted infantryman has effectively zero chance of even engaging them. It's sort of like trying to fight aircraft with AA guns, at best. You need to park huge numbers of AA guns all over the place, and most of them will not actually engage the enemy at a given time, because the aircraft can pick and choose where to fight and you can't stop it.

Now up the ante by making it hard to use a single AA round to shoot down a single plane- Gundams are relatively better armored against antitank missiles than planes are against 20-30mm cannon shells. That strategy starts to break down.

Simon, it sometimes seems that some mobile suits don't have meaningful armour at all (ie can't stop common peer weapons) but have very strong shields instead. Given the emphasis on agility the shield is certainly more useful than the same mass of armour spread over the suit, but I think they use specific materials/manufacturing/active systems to make them as resilient as possible. The RX-78-2 wouldn't have that sort of thing though; I think its shield is made out of thicker armour.

Well, you could do a lot worse for a shield than a big slab of Chobham armor or whatever cut in the shape of a kite shield. That said, if you say the suits don't have serious armor capable of stopping (light) antitank weapons on their hull, then yeah forget what I was speculating about earlier.

All things considered, a robot's shield would act pretty much like the side skirts on a tank. I personally doubt the shield would be thick enough to decap an APDS round unless the angle of impact is extremely favorable to it. Might cause some wobble to the round too as the fins on the round would break off when going through the shield. Don't know if this would affect the penetration of the main robit armor in any meaningful way. The distance between the shield and the robot's body is pretty small so the round doesn't have a lot time to tumble.

As noted, it depends on the composition of the armor, too- the shield seems to be the main 'armor belt' of the unit, so if it's made of materials noticeably better than modern armor it might very well have an effective thickness* thick enough to present a serious problem for even sabot rounds.

*(as measured in 'rolled homogeneous armor,' which is what people mean when they say "blah blah distance RHA," guys)

[Gunhead]

]As noted, it depends on the composition of the armor, too- the shield seems to be the main 'armor belt' of the unit, so if it's made of materials noticeably better than modern armor it might very well have an effective thickness* thick enough to present a serious problem for even sabot rounds.

*(as measured in 'rolled homogeneous armor,' which is what people mean when they say "blah blah distance RHA," guys)

Armor composition would matter, but I think Stark's estimate on the shield 50mm of thickness is a bit high. More like 30mm range would be more likely due to weight. If we use RHA as the measuring stick, with modern composites that would be something like 60mm of RHA base thickness. Even if the future fantastic materials make it 90mm RHA, you'd still need to place the shield in an angle against the incoming round to have a measurable effect on penetration. This is because you want to try and bend the incoming sabot when it travels inside the armor and at the same time make the tip and body of the sabot travel at different speeds to cause it to break up. If your absolute thickness is just 30mm, the round will have penetrated through before this really starts to happen. This leaves just the thickness the round has to pass through that will absorb some of the energy but the absolute thickness of the plate would not be enough to cause the round to start bending in any meaningful manner. This is also why RHA figures are not very useful when trying to estimate penetration against unknown, or even known, armor configurations because it just gives us the "raw power" figure without telling us how the round will behave against the armor.

-Gunhead

[Connor MacLeod]

I know essentially nothing about Gundams, but if the shield is a serious thickness of armored material, capable of stopping credible antitank weapons, and if the Gundam itself is armored to roughly tank-scale... yeah, the shield will be effective. Even if it's penetrated by an antitank weapon, the resulting projectile/shaped charge/whatever will typically be in no shape to punch through yet another layer of armor. That's why spaced armor exists in real life, along with concepts like "decapping plates" and "skirt armor."

The reason 0079 can stop the 120mm machine guns is because its a newly built, highly experimental, and VERY advanced suit at the start of the series, and generally was superior ot much of the earlier mobile suits. That would obviously go for the shield as well. Later on in the series, however, Zeon managed to make advances in its own mobile suit technology and produced designs that could challenge/threaten the Gundam, so that superiority didn't last.

Its also debatable, as I said, whether the Mobile suit machine guns are directly analogous to tank guns. I remember Ford mentioning in MS 08th Team that one Zaku unit had a guy packing a huge anti-tank gun that was lifted from one of the Zeon Main Battle tanks, and it was more powerful (but slower firing) than the machine guns they use (which may be, as I said, due to recoil.) There are also cases where the machine guns are distinctly subsonic anyhow, but its quite likely that mobile suit guns have experimented with all manner of projectiles at various points just like RL weapons, so some sort of APFSD/HEAT/etc. may exist (either to give them an advantage against other sorts of vehicles, or to facilitate their ability against other mobile suits.)

All that said, good point about the shield as an analogue to spaced armor. That's something I hadn't thought about.
And even with AP projectiles if the round penetrates the shield it may have lost enough velocity that it can no longer penetrate the mobile suit's 'skin'. Or maybe even glance off.

I don't think the "APDS for the win" approach Gunhead talks about would work well either against that, he's right there. Sabot rounds have a record of punching through lots of relatively soft, crumbly stuff (like sand dunes and apartment buildings) to knock out a tank on the other side, but I'm not sure whether they could penetrate a large slab of armored material, especially an angled one, without starting to tumble and breaking up.

I'm not realyl sure we can call mobile suit armor uniformly 'slabs of armor' like thats the intent behind it. For example there was a Gundam unit in 'Stardust Memory' whose sole purpose was to deliver a nuclear attack (And survive such) as a response to mobiel armor technology, and it was much bigger/bulkier than regular mobile suits due to all the protection. But its 'protection' - including the shield - incorporated tons of heat dissipation/cooling bits to help its survival, but it also means its highly specialized and not neccesarily able to stand up to just ANY kind of attack. And mobile suits use a wide variety of attacks - explosive muntiions, kinetics, beam weapons (mainyl particle beams, but I'm pretty sure lasers get used too) and what might work against one attack won't against another.

On top of that many (but not all) 'Gundam' type units (or similar) can either be 'signature' units for whatever reason, or they may be highly advanced prototypes (like Amuro's unit in 0079.) That can mean that they are simply 'better' because of either more advanced tech (comparatively) or because more resources/expenses were put into a spcial unit for a special person (which is sometimes the case in Zeta.) So what works for certain mobile suits may or may not work for others.

[Connor MacLeod]

If you're looking for massive after armor effects, a full bore AP round will seriously fuck up anything it hits provided it can penetrate the armor of the target. Which is something to remember when talking about future fantastic vehicles which easily lack internally stored fuel and ammunition, which are the reasons why depleted uranium shots are so effective combined with their penetrating power and are used as the main type of anti armor round in tanks today.

-Gunhead

Thats actually a very good point. APFSDS is very efficient at penetrating and damaging certain kinds of targets but I'd wonder if it would hold in all cases. I mean IRL there are lots of different kinds of warheads used by different kinds of craft for different kinds of purposes.

For some odd reason I keep going back to some sort of organic analogy - AP rounds may actually very easily penetrate a mobile suit where it wouldn't penetrate a tank, but unless it hits something vital it may not do any serious damage (simply blasting away the legs won't always help either, because mobile suits can fly and even hover, especially in later-era UC series.) so it could be that the projectiles intended for use on mobile suits focus less on penetration and more on (for example) explosive effect.

This is also why, again, I think assuming that a mobile suit is meant to be an analogue to a tank is false, because the series makes it rather clear they're not.


Also: re the whole angling thing. It may not just be a matter of adjusting the angle of the shield by the arm, but actual placement/manuevering of the mobile suit. The arm may just be more for 'fine positioning', whilst they rely on position and thrusters to provide more of the advantage of 'angling.' For all we know, head to head engagements against someone using dedicated AT weaponry is suicide for a mobile suit because even teh shield isn't meant to take direct hits from tank weapons.

[Ritterin Sophia]

Its also debatable, as I said, whether the Mobile suit machine guns are directly analogous to tank guns. I remember Ford mentioning in MS 08th Team that one Zaku unit had a guy packing a huge anti-tank gun that was lifted from one of the Zeon Main Battle tanks, and it was more powerful (but slower firing) than the machine guns they use (which may be, as I said, due to recoil.)

To be fair, in the scene you're talking about the 175mm cannon demonstrates a muzzle velocity in excess of 5km/s as we see from the time of firing to impact on a target 10km away was less than two seconds (7:38-7:40 marks). That's a substantially higher velocity than we see out of guns like the L/44 and L/55 120mms used on modern Leo 2s.

[Ford Prefect]

His conclusions on the improved power of the Leopard's gun is based on it being in the same setting as Tactical Surface Fighters, which have more showings in the various Muv Luv media and so all sorts of estimates about capabilities which don't make a great deal of sense when you think about it, but he's from Narutoforums/OBD so you know :v

[Connor MacLeod]

His conclusions on the improved power of the Leopard's gun is based on it being in the same setting as Tactical Surface Fighters, which have more showings in the various Muv Luv media and so all sorts of estimates about capabilities which don't make a great deal of sense when you think about it, but he's from Narutoforums/OBD so you know :v

Nonsense. Its perfectly reasonable to establish the KE lethality of a round from the Mohs hardness scale. And anyone objecting is 'overanalyzing' fiction and doing it wrong. We can't expect sci fi to be consistent all the time!

This is actually a very easy trap to fall into when you aren't aware how limtied your knowledge is. I've done it on more than one occasion and its screwed up my calcs before.

Ironically the best example is also tank based when it comes to the 'honour guard' 190 tons of recoil force thing. Its not something you can do a straight, simple comparison on, yet it took me years to actually figure it out, and thats because of that limited knowledge/problems with how I looked at it.

[Connor MacLeod]

Its also debatable, as I said, whether the Mobile suit machine guns are directly analogous to tank guns. I remember Ford mentioning in MS 08th Team that one Zaku unit had a guy packing a huge anti-tank gun that was lifted from one of the Zeon Main Battle tanks, and it was more powerful (but slower firing) than the machine guns they use (which may be, as I said, due to recoil.)

To be fair, in the scene you're talking about the 175mm cannon demonstrates a muzzle velocity in excess of 5km/s as we see from the time of firing to impact on a target 10km away was less than two seconds (7:38-7:40 marks). That's a substantially higher velocity than we see out of guns like the L/44 and L/55 120mms used on modern Leo 2s.

As I mentioned before Ford's brought that scene up before and it allows for upwards of 10 km/s velocity for the round. Which leads to all sorts of hilarity for KE and momentum.

Thing is, tank rounds aren't something you can just go MORE KE or even MORE MOMENTUM and assume its automatically better. In line with Gunheads' comments on it, its alot more complicated than that, and there's a whole slew of tradeoffs to consider.

Likewise, there are considerations of recoil, penetration (a big part of tank rounds is that more velocity does not mean more penetration automatically.. there's a point of diminishing returns there.) and various other things that consistency demands. REcoil is always the big one for me, but its not something most sci fi fans want to consider (for whatever reason. Lots complain whenever I bring up the 'recoil' issue, whether its firearms or tank guns or whatever.)

[Ritterin Sophia]

It's interesting to me that OP doesn't feel the need to actually defend his arguments here and simply makes a minor change to go repost the vs on another forum.

[Stark]

Like I said, people who make these threads don't want a discussion - they want 'hurf durf robits suck'. They want 'and then KAPOW the super bullet kills the man!'

I mean doing zero research I can bang on about technological and design elements in Gundam off the top of my fucking head; it's not hard to do. Why can't he do the same for Muv Luv, a setting I happen to think is pretty sweet? It's probably because he doesn't actually have any understanding of it or any ability to discuss it and just wanted cheerleading.

[Connor MacLeod]

It's interesting to me that OP doesn't feel the need to actually defend his arguments here and simply makes a minor change to go repost the vs on another forum.

Of course he doesn't need to defend it. We're clearly making unreasonable expectations on him to have internally consistent calcs with the same science he uses to crunch the numbers.

Internal consistency is important. He went all out on me how it was 'unreasonable' to expect sci fi to be totally consistent or plausible/realistic. He woudl have a point... except for the fact he wants to use science to do calcs. If you're going to do calcs rather than black-boxing it, there are certain requirements that one has to adhere to re: doing the calcs if one does not want to be a hypocrite. KE calcs tend to be one of those things.

I think the worst part is that he doesn't evne realize the flaws exist in his own calcs. HE literally assumed 'equal to diamond' then assumed it would take X amount of energy to punch through. Except, you know, diamond is fucking brittle, and brittleness is not a good quality for armor - at least not by itself. Chobam armor IIRC makes use of relatively brittle ceramics as apart of its defensive makeup, for example.

EQuivalence calcs like that are tricky when you're cherrypicking form sources because it assumes the two facts do in fact relate - something I have learned (from hard experience - again Conqueor recoil clacs) does not follow.

[Connor MacLeod]

I mean doing zero research I can bang on about technological and design elements in Gundam off the top of my fucking head; it's not hard to do. Why can't he do the same for Muv Luv, a setting I happen to think is pretty sweet? It's probably because he doesn't actually have any understanding of it or any ability to discuss it and just wanted cheerleading.

It may be a phenomenon with the narutoforums itself. Without having spent any time there and having my sole experience being all these calcs I get thrown at me from various anime, it could simply be that the knowledge pool within that forum is closed - if there is little interaction with alternative approaches outside that forum, its very easy to convince yourself you've got the right approach to things, becaues noone ever questions it or challenges it. And challenging/testing ideas is, whilst unpleasant, an important part of analysis.

[Sea Skimmer]

I think the worst part is that he doesn't evne realize the flaws exist in his own calcs. HE literally assumed 'equal to diamond' then assumed it would take X amount of energy to punch through. Except, you know, diamond is fucking brittle, and brittleness is not a good quality for armor - at least not by itself. Chobam armor IIRC makes use of relatively brittle ceramics as apart of its defensive makeup, for example.

The actual point of the original Chobam was to break on large scale, and in the process release energy stored inside it by the manufacturing process causing expansion which forced more mass of the path of the shaped charge. Great against a single shaped charge hit, but not much else. Against long rods this is much less effective and that's why the second and later generations of such armor concepts, called Dorchester by the British, incorporated high density metals, mainly DU or titanium mesh, which led to a huge increase in vehicle weight in the process. They also changed the ceramic and composite materials used several different times until nothing was left in common with early systems and greatly modified all aspects of its performance in the process. All these armors are very dependent on the sandwich effect, any one material would be crappy alone. Even for fairly systems like body armor the specific hard plates are some kind of layered system, like sintered silicon carbide with a glued on spectra backing. I suspect if you took the original Chobam ceramics and had the missile actually explode against it, without the steel shell, it'd literally be blown apart.

[Vendetta]

I suspect if you took the original Chobam ceramics and had the missile actually explode against it, without the steel shell, it'd literally be blown apart.

Well yes, being blown apart is the point of the ceramic layer, by being blown apart it expands and deforms the other layers which increases the thickness of the armour from the point of view of the penetrator.

Chobham is incredibly effective against even multiple shaped charges, there are instances of Chobham protected tanks surviving 50+ RPG hits in Iraq (both M1s and Challengers).

Like I said, people who make these threads don't want a discussion - they want 'hurf durf robits suck'. They want 'and then KAPOW the super bullet kills the man!'

Which makes it odd that he chose Muv-Luv, where the primary means of fighting is actually, well, robits. (Which is even in the wiki he linked to - All our weapons are useless = build us some robits)

[OmegaChief]

Like I said, people who make these threads don't want a discussion - they want 'hurf durf robits suck'. They want 'and then KAPOW the super bullet kills the man!'

Which makes it odd that he chose Muv-Luv, where the primary means of fighting is actually, well, robits. (Which is even in the wiki he linked to - All our weapons are useless = build us some robits)

Perhaps he somehow thought of Muv-Luv as more 'Realistic' or something then Gundam, and that obviously if they can built robits then their tanks must be at least on par with them or something?
(Of course this totally ignores the tanks in Gundam and other similar shows or even the GUNTANK [Which remains hilarious] so I could be totally wrong.

Though on a related but slightly different topic, why are so many people all 'lulz robits unrealistic and silly' (Okay they can be silly but can't everything?), I mean hell I have a friend who's a big Sci Fi and fantasy fan, loves 40K, won't even give a mecha show a try to see if he'll like it or not because of argument, despite how the shows recommended are good for characterisation, interesting storytelling/themes and internally consistent with how their robits work and the implications of the technology and justifications for them, it's pretty damn annoying.

[Vendetta]

Perhaps he somehow thought of Muv-Luv as more 'Realistic' or something then Gundam, and that obviously if they can built robits then their tanks must be at least on par with them or something?

I dunno, because the setting for Muv-Luv is apparently modern day*. As in right now. Except in the '70s suddenly aliens and our weapons are useless, build robits. (At least build robits instead of planes, all the robits are named after fighter planes).

So it doesn't even have the excuses of it being in the future and mobile suits being designed to operate in space where, allegedly, the benefits of articulation for weapon systems outweigh the inertial issues of having limbs everywhere.


* Given that it's a visual novel there's precisely zero chance I'll ever play it because that's below even my miniscule standards for gameplay. Every time anyone mentions it I keep thinking "man, if only it were a strategy rpg/SRW clone, I would totally play that".

[Connor MacLeod]

The actual point of the original Chobam was to break on large scale, and in the process release energy stored inside it by the manufacturing process causing expansion which forced more mass of the path of the shaped charge. Great against a single shaped charge hit, but not much else. Against long rods this is much less effective and that's why the second and later generations of such armor concepts, called Dorchester by the British, incorporated high density metals, mainly DU or titanium mesh, which led to a huge increase in vehicle weight in the process. They also changed the ceramic and composite materials used several different times until nothing was left in common with early systems and greatly modified all aspects of its performance in the process. All these armors are very dependent on the sandwich effect, any one material would be crappy alone. Even for fairly systems like body armor the specific hard plates are some kind of layered system, like sintered silicon carbide with a glued on spectra backing. I suspect if you took the original Chobam ceramics and had the missile actually explode against it, without the steel shell, it'd literally be blown apart.

Which brings up another interesting question I was considering with this guys calcs. Whilst I'm not the most well-informed on materials science and tank guns, I'm pretty sure that the way modern tank rounds (especially kinetic energy penetrators) work is far different than he is assuming. I recall reading that penetration by Kinetic energy penetrators behaved differently than, say, WW2 era projectiles, because the means of penetration was different due to the differences in velocity, shape of the round (smaller cross section to concentrate force on a smaller area) and density. I think it was related to hypervelocity impacts itself but I wasn't sure if it was quite the same things (I remember materials behaving more like fluid but not actually like, melting, whereas hypervelocity stuff is way more.. explosive, and that actually degrades penetration. Which is also why 'faster isn't laways better' with tank rounds too, now that I am thinking of it..)

Just thought I'd double check.