BR350A and B HE fuse and Pzgn39 HE fuse

[John Kettler]

c3k,

I would add that the impact, depending upon angle, can, depending on how fast penetration actually occurs, also be degraded by transfer via the suspension. There are plenty of accounts, from multiple wars, of AFVs rocking when hit by KE projectiles. It's in THE HEIGHTS OF COURAGE, TANKS FOR THE MEMORIES and others I don't presently recall. The Desert Storm accounts also talk about this, I believe.

I have presented case after case in which only a marginal penetration by AP shot occurred, and where that didn't do much (see Panzer IV/D driver inter alia) not only was the crewman still functional, but so was the tank. The Beda Fomm tests, Major Jarrett and Lt.Col. Gruver all show and tell us what happens when APHE penetrates only halfway into the fighting compartment and detonates.

This is the point upon which I've hammered away in multiple threads. If AP shot doesn't enter with enough residual KE to actually punch through the armor, rather than simply pushing it aside via hyperplastic flow (evidenced by the petalling seen on penetrated Shermans in period pics), then it doesn't do much--unless you're Italians in a tank with brittle armor and rivets. Different game, that!

So, in my view and of ArgusEye, the APHE provides tremendous damage potential (generally killed the British tanks outright in the Middle East) in cases in which the KE could do little or nothing. At closer ranges, it was even nastier, because the KE of the projectile proper also increased, adding to the energy transferred, armor displacement, spalling, etc. Then it went off!

Regards,

John Kettler

[c3k]

John Kettler,

Suspension "rock", see my bold, below:

I agree that the propellent in the ammo is the primary means of destroying a vehicle. (And I like your final sentence...that needs to be up on a wall in various armor schools somewhere.)

If the ammo cooks off (talking strictly WWII tanks!), the men inside will die.

However, another method of taking out the tanks exist, and that is wounding the crew.

The loss of KE due to penetration is significant, unless the armor is overmatched by orders of magnitude. Examples: 88L70 vs. Stuart; US Abrams vs. well, a lot. In other matchups, say a 75L48 vs. Sherman frontal armor, the loss of energy is significant. In that case, the burster charge makes a difference.

That burster charge creates large chunks of hot metal traveling at significant velocities inside the tank. Yes, the PENETRATION also produced chunks of hot metal traveling at significant velocities. More chunks of hot metal flying around the inside is better at achieving the goal of killing the crew or cooking off ammo.

More is better.

If the KE which is delivered to the target tank is changed to heat the armor, that is worthless for killing the tank. Any energy which deforms the armor is worthless. A dented tank can still fight. Any energy which is used to transfer momentum to the target tank is worthless. What matters, as you've alluded to, is the energy dumped inside the fighting compartment. Then, once that energy is delivered INSIDE the tank, what it does in there is critical.

My question still stands: how much energy is used in penetrating the armor?

(Rexford would know. RIP.)

Thanks,

Ken

Regards.

[PzKpfw 1]

A few quick general comments:

PzGr.39 APCBC did ignite Sherman stowage, and the filler was the main cause determined in Ordinace tests to find out why the Sherman brewed up so easy, well that and the fact US crews stowed upto 40xtra rounds all over the turret floor etc. Which mreant that an frontal penetration from PzGr.39 or SC from a MPAT would rupture the ammo caseing causing a propellant fire. The US dealt with this in 2 ways, 1, applique armor, and wet stowage. 60 - 80% of off dry stowage Shermans burned out in 1944 - vs 10 - 15% of wet stowage M4A1, M4A3 Sherman in 45.

The Tiger II had the same problem with the turret racks igniteing, which led to their remova or lack of usel. IS II 122mm was stowed in 2 parts warhead & propellant which were also vulnerable to APCBC ignition on full or partial penetrations where the cap ignited.

It's not generaly known but prior to Desert Storm M1A1's were fitted in country with xtra spaced plates in the field because it was feared Soviet 125mm HE/Frag could on repeated hits on the hull open up the chobham armor.

Regards, John Waters

[John Kettler]

Some comments on U.S. experience with KE damage to tanks, absent penetration. The U.S. got the bright idea of using an obsolete manned M103 heavy tanks (M48 on steroids to counter IS-3 and IS-10 heavy tanks) as moving targets for inert warhead TOW missiles live fired.

No one was more surprised than the crews of the M103 when the TOW impacts smashed in all the periscopes, vision blocks and such, driving the parts back into the fighting compartment. The pieces were replaced, armored housings were fabricated and installed, and firings resumed. The optics still got smashed in, at which point the M-103

were converted to radio control and the crew removed permanently.

Here is what I had to say on the matter some time ago, in a Katyusha effectiveness thread.

http://www.battlefront.com/community/showthread.php?t=89784&page=3

c3k,

At the time the BM-21 entered service, the 9M22 rockets it fired were a serious threat to the tanks of the period. We know this because tests with inert TOW missiles against M103 heavy tanks with live crews in them found even a propellant spent TOW quite capable of doing personnel endangering damage from impact forces alone against a buttoned tank. Sights, vision blocks, cupolas and more were smashed in scary early tests, necessitating special armoring of such kinetic weak spots. ISTR shock forces were also jamming the turret on occasion. Nor is there any doubt that a direct hit followed by warhead detonation would be very bad news for, say, an M48.

From this, I conclude that a better strategy for heavy guns that can't penetrate is to simply fire unfuzed/fuze well plugged shells and rely on shock effects, as outlined above, to at least disrupt the crew.

Regards,

John Kettler

[John Kettler]

Bigduke6,

From Valera Potapov's site (helped BFC on CMBB), Russian Battlefield (Fair Use)

http://english.battlefield.ru/js-2.html

t the end of the war, each Tank Corps should have at least one Tank Regiment of JS-2 tanks, which were best for breaking through a heavily entrenched enemy line. A single 122 mm shot could penetrate the armored cupola of a concrete bunker, or shatter the main redbrick walls of the Konigsberg. At that time, an infantryman with a Faustpatrone, a Panzerfaust, or even a Panzerschreck, became the most dangerous enemy of the JS-2. Russians didn't distinguish these weapons and called them all "faust". Thus, an infantryman with a "faust" was called a "faustnik". During street fighting, about 70% of destroyed tanks were hit by "fausts".

From the beginning of 1945 Soviet tanks received shields of various designs. These shields were intended to protect from HEAT munitions (e.g. "fausts"). Most of these shields only protected turret, whilst hull remained unprotected. That was not so bad, as many people think now, because over 80% of "faust" hits were on the turret side. A shaped-charge round would completely destroy the shield, but leave the main armor unbreached, leaving a small black hole in it. Soviet tankers called such holes as "the kiss of the witch".

Unfortunately, these shields might be torn off by a shell, or explosion. The result could be fatal. Lieutenant-Colonel V.Mindlin (a participant of battles for Berlin) wrote in his memoirs "The Last Battle - the Hard Battle!" about this:

"Here is a tank with battened down hatches... but the crew is silent. They respond to neither radio nor knock. There is a small hole with a diameter no more than a cent. That was a "faust", that was its work. A shield was torn off, and a next round penetrated the armor...

Those who saw a tank battle knew how terrible death could be for tankers. If a round hit the ammunition or fuel tanks, a tank would be destroyed at once - just blast off and the crew perishing without any torture.

Often a round just penetrates the tank's armor but doesn't hit the ammunition or fuel tanks. All crewmembers are wounded, their tank is burning, but the crew is unable to extinguish the flame. They need to escape the tank and run off to a safe distance. However, the tankers are wounded and they simply can't do that, they can't open the locked hatches. And you can hear the cries of those being burned alive. You can't help them because the hatches are locked inside..."

It was very dangerous to fight with open hatches (and prohibited, by the way) because enemy infantry could throw a grenade into a tank. Thus, all crews received an order to close hatches but not to lock them. As a result the losses crew were reduced."

The link above also includes assessments of IS tanks versus several key German tanks.

http://english.battlefield.ru/was-the-tiger-really-king.html

This one has firing trial analyses conducted by the Russians at Kubinka against a captured King Tiger. Either the testing methodology and/or the report writing are off, because things get muddled and it's difficult to follow which projectile was used when and did what. It's clear, though, that artillery type weapons, such as the 122mm and 152mm, could inflict considerable damage, a condition magnified by deteriorating German metallurgy.

JasonC is probably not going to like the part which concludes the U.S. 76mm ammunition is way better than the Russian domestically produced 85mm ammo.

"10. American 76 mm armor-piercing projectiles penetrated the "Tiger-B" tank's side plates at ranges 1.5 to 2 times greater the domestic 85 mm armor-piercing projectiles."

Regards,

John Kettler

[PzKpfw 1]

The difrence between US 76mm & Soviet 85mm ammunition performance is realy not that supriseing due to quality of manufacture & material. The Sherman in internal Soviet reports was superior to the T-34 in several areas, ie, optics, turret traverse speed, mechanichal reliabity, gun performance etc. Soviet complaints concerned the narrow tracks which hindered Xcountry performance in mud/snow conditions.

Regards, John Waters

[John Kettler]

PzKpfw1,

You left out the clinometer! It was so good the Russians removed them from the M4A2s and gave them to the artillerymen, who prized them greatly. The Russians weren't interested in indirect fire from tanks, so no great loss. Read about the clinometer and all the other Sherman marvels here.

http://www.questia.com/library/1476737/commanding-the-red-army-s-sherman-tanks-the-world

Regards,

John Kettler

[Bigduke6]

Thanks guys.

I think one of the lessons I draw from this is that a tank is a tank, but these shells have considerable mass and penetration or no penetration, bursting charge detonation or no, at the end of the day all these shells have considerable mass and velocity, and so energy.

In digging around on this subject I find that the Soviets chose the 122mm for IS-2 specificially because of all the guns in the Soviet inventory it was the one that turned out to be most effective at Kursk. I.e., more than the 85mm AAA cannon and more than the 152mm in the tank destroyers. (They also stuck with 122mm when the even more effective 100mm became available on grounds of mass production, but that's another thread)

Anyway, now when BFI gets around to doing an update on CMBB (well they should) I will be more confident when arguing a mucking big explosion on the outside of a tank, without penetration, should have a chance of causing substantial damage.

It makes sense to me the 76mm would penetrate the side of a Tiger better than an 85mm: smaller cross-section, higher velocity. I've read the Kubinka report on shooting up that captured Tiger II; one of the things the Soviets found out was that a good (proportion) of the test shots by 76mm and even more by German 88mm went in one side and out the other.

I'll leave it to other to discuss whether that means Soviet 85mm and 122mm could be more effective than those higher-velocity rounds, as they did not produce through-and-through performance and so necessarily would burst inside the crew compartment.

On the relatively poor mobility of the Sherman there is a good Soviet story about that. When the Soviets decided to attack Japan Manchuria was named the target, and the formation that got the mission to break into the Japanese rear and drive several hundred km and make the main thrust of the offensive, was 6th Guards Tank Army.

6th Guards Tank Army was a somewhat interesting formation from the equipment POV as its main armored components, 5th Guards Tank Corps and 9th Guards Mech Corps, apparently were equipped respectively with T-34/85 and Sherman M4. The route of 6GTA's advance took them through the passes of the Greater Hsingan Mountains, which, unsurprisingly, had steep and undeveloped roads. The story is that 9GMC initially led the advance, found its Shermans unable to climb the mountain tracks, and so 5GTC had to take over. The best way to get a Sherman over the Greater Hsingan, the accounts went, was to use a T-34 to tow it.

For those interested in Soviet tanks 6th Guards also is interesting in that there have been rumors/unsubstantiated references bouncing around for years that the Soviets may have fielded and actually sent into combat IS-3 during the Manchuria campaign. If this took place then the logical unit to have done that would have been 49th Guards Heavy Tank Regiment, which was organic to 6GTA.

[John Kettler]

Bigduke6,

This site has some penetration range comparisons, but I can't tell whether the "JS 122" is a tank or an SP. I think it's a badly characterized tank. Wish I could track down the article from FINE SCALE MODELER in which a Panther takes such a resounding 122mm hit that it smashes through the glacis, the firewall, into the engine, then blows the remains of the engine out the back of the tank. I believe that was in connection with a review of an ISU-122 model.

http://dietmagic.tripod.com/panther.html

HSU Dmitry Loza's book DEFENDING THE SOVIET MOTHERLAND talks about his August Storm experiences in Manchuria, to include the bizarre presence in the attack of BT-7s! Sadly for the scenario writers, not one survived the trek over the Great Kinghan range!

Regards,

John Kettler

[PzKpfw 1]

PzKpfw1,

You left out the clinometer! It was so good the Russians removed them from the M4A2s and gave them to the artillerymen, who prized them greatly. The Russians weren't interested in indirect fire from tanks, so no great loss. Read about the clinometer and all the other Sherman marvels here.

http://www.questia.com/library/1476737/commanding-the-red-army-s-sherman-tanks-the-world

Regards,

John Kettler

John, thx for the link. I also left out, that the internal reports also stated the Sherman's track shoes had a longer lifespan then the T-34-85's engine.

Also thank you for the links on the film footage of the tanks etc. Watched some with my son's last night. I wish the narrators or whomever did the research was a bit more thourogh as the Firefly was not the equal of a Panther or Tiger E, only its gun was on par with them.

Theirs one video of a M4 & M26 that graphicly shows the M4 TC crawl out of his hatch after hit missing a leg, the sticky notes arrows the guy put on illustrateing it dont say much, yet when the M26 KO's the Panther he writes the 'brave crew' that turned me off to his vids.

Regards, John Waters

[PzKpfw 1]

Concerning HE filler in Soviet rounds, they used a small HE cavity. The rounds had an short ogive & a blunt nose with an thin ballistic windsheild.

Their rounds differed from the other nations in that Soviet rounds used grooves, located either in front of, or at the bourrelet. These grooves were described as localizers and were designed to prevent the HE filler from pre mature detonation on impact, so that the round delivered its full filler charge behind the armor in the targets fighting compartment. After WW2 the Soviets developed a blunt nosed, AP capped round with an ballistic windsheild. Ie, German PzGr.40 APCR ammunition originaly used an solid aluminum and/or magnesium windscreen, to achieve an behind the armor incendiary effect after the round had penetrated the plate.

The reason for the use of a windscreen was because of Polte's work on shell carrier crush up. Later in the war as material shortages became prevailent the Germans used plastic or thin steel for the windscreens. The Soviets used aluminum windscreens on some of their KE rounds. The Germans did not appreciate the performance of Russian ammo, evidence as Lorrin Bird (Rexford) detailed in posts many moons ago. Research also sugests, the Soviets were unaware, of the behind the armor incendiary effect of a ballistic windsheild as well until well after the war.

Regards, John Waters

[ArgusEye]

The difrence between US 76mm & Soviet 85mm ammunition performance is realy not that supriseing due to quality of manufacture & material. The Sherman in internal Soviet reports was superior to the T-34 in several areas, ie, optics, turret traverse speed, mechanichal reliabity, gun performance etc. Soviet complaints concerned the narrow tracks which hindered Xcountry performance in mud/snow conditions.

Optics? I find that very surprising. I used to collect WWII tank optics, and even the mid-war T34 optics were superior to even the post-war (1948) Sherman optics by some margin. Throughout the war the pecking order was German > Russian >> French > American > Brit > Italian

in all significant ways.

[ArgusEye]

[...] These grooves were described as localizers and were designed to prevent the HE filler from pre mature detonation on impact, so that the round delivered its full filler charge behind the armor in the targets fighting compartment. [...]

Not quite: the grooves were stress risers that would cause any breaks initiating in the rear of the projectile upon impact not to propagate into the nose (diverting into the grooves), shattering the entire projectile. This way the rear of the projectile might shatter (releasing the burster, rendering it useless), but at least the nose might still penetrate.

[ArgusEye]

I would add that the impact, depending upon angle, can, depending on how fast penetration actually occurs, also be degraded by transfer via the suspension.

In the case of a 6kg round hitting a 30000kg tank at ~750 m/s, we can safely state that this energy loss to rocking the entire tank is going to be insignificant by five orders of magnitude. If we could get LaTeX on this forum I'd be happy to show my work, but I'm going to spare my fellow grogs my exhibitionism for now.

[ArgusEye]

The point of entry of the round into the tank is an explosion, nothing less. In a small fraction of a second, a steel wall several inches thick and across is basically vaporized. The round and the volume of metal it displaces from the wall are comparable in mass, and the round was traveling twice the speed of sound before it hit. If the plug coming out remained intact you'd be playing billiards with 2 cannonballs after the collision each going about the speed of sound and weighing tens of pounds. Normally it doesn't, and instead the armor wall is sprayed into the interior in fragments and shards. But just like any explosion, you also get an overpressure wave into the tank interior.

Where do you get this ridiculous twaddle? The air pulse from being displaced by a round coming into the tank is slightly *less* than outside of the tank (after armour it's slower) and it's rather sub-lethal even there. Cartwheeling doesn't happen at the scale typical for tanks, and as for vaporizing anything... I want some of what you're smoking.

It is also possible they died in flash fires of exposed propellant that did not do appreciable additional damage to the tank's systems, because they happened to not set off any additional ammo. A flash fire of powder can be over in less than a tenth of a second, and kills by overpressure (not burns).

Flash fire kills by burns if it is not going high-order. That's one of the uncomfortable facts tankers have to live with. Thence the oft-heard memories of tankers screaming as they burn to death. The amount of heat from even a single 75mm propellant charge is enough to heat the entire inside of the tank to flesh searing levels, but the pressure doesn't build up because the propellant isn't properly enclosed. The deflagration speeds up when the pressure goes up, and it goes exponentially. If the pressure builds enough to kill the crew the chance becomes very slim that it will not explode to high order levels and just blows up the entire tank. The mechanism is illustrated clearly in this Syrian video:

Any actual direct hit by a 122mm round would dump a huge amount of energy onto the target in a very short period of time, and even if the armor held, could easily stun the crew. HE isn't needed for that effect and actually detracts from it - it scatters energy away from the axis of the round's flight.

After colliding with a tank the round will have transferred all the shock it's going to transfer, and if it doesn't damage the tank, the tank is going to rock a little. The physical shock to the crew will typically be about similar to firing their own main gun. Detonating kilo's of TNT just outside will really give a nasty shockwave, which will -at least- knock the breath out of your lungs, blow sight blocks in, and stall the engine.

[PzKpfw 1]

Optics? I find that very surprising. I used to collect WWII tank optics, and even the mid-war T34 optics were superior to even the post-war (1948) Sherman optics by some margin. Throughout the war the pecking order was German > Russian >> French > American > Brit > Italian

in all significant ways.

All i can relate is the internal report says the Shermans optics were better then the T-34/85s. Intresting as the Soviets copied British optics as well.

Regards, John Waters

[PzKpfw 1]

Not quite: the grooves were stress risers that would cause any breaks initiating in the rear of the projectile upon impact not to propagate into the nose (diverting into the grooves), shattering the entire projectile. This way the rear of the projectile might shatter (releasing the burster, rendering it useless), but at least the nose might still penetrate.

Bakhoffens(sp) article on KE develepment described them as localizers, and their function as related above. Thx for the additional info.

Regards, John Waters

[ArgusEye]

All i can relate is the internal report says the Shermans optics were better then the T-34/85s. Intresting as the Soviets copied British optics as well.

Odd. I wonder what criteria they used. Who was doing the reporting? And not unimportant, when? My experiences are quite different. The T34/85 gun scope I played with was quite good.

[PzKpfw 1]

Argus the report is from 3rd GMC IIRC from 1944 mid to late. Interesting as i have never seen any reports etc that stated T-34-85 optics were better then US optics. From the US reports on the T-34-76 & 85. Kip if he is still around had IIRC access to the British reports on Soviet optics.

What T-34-85 sight did you play around with? was it the PTK-5, TSh-16, or MK-4?.

Regards, John Waters

[ArgusEye]

A bog-standard TSh-16. It wasn't in good shape when I bought it, and I committed some archaeological heresy by fixing it. I never got it completely to spec, but I did get it back in more-or-less working order. I made some profit when I sold it. It was surprisingly good, especially because it looked so cheap and clunky.

An expensive hobby, with very little pay-off. Luckily I could sell off most of my collection. I still have an M71G I can't sell off to anyone for the price I paid.

Interesting that they thought it was the other way around in '44. I trust they were right somehow, but I'm trying to figure how. Maybe I got a good specimen? Maybe they got a bad one? Maybe the Sherman optics deteriorated with time?

[Streety]

Perhaps this now needs a new thread of its own?? But I too found Argus' initial tank optics pecking order: "German > Russian > French > American > Brit > Italian" a bit odd - assuming we're talking about overall optical capability (magnification, field of view and range-finding) and quality of manufacture.

I always understood German lens quality was the best - and this was still the case long after the war (I worked in British naval design in the 1980s-90s and on maintenance of older ships and subs - some back to the late WW2 era - where everyone I knew took Ziess to be the best).

No surprise there, perhaps. But I was also under the impression that early-war Soviet tank optics were based on pre-war British and Polish designs and that late-war Soviet optics were copies of German design (or even captured German optics from German factories they over-ran in 1944/45. American tank optics were (I understood) less good than British mainly because US optics such as in the M4 lacked the range-finding capability of British tank optics (which were still second to German ones, of course). This appears to have been borne-out by the late-war Pershing tank adopting British optics (or so I'd read). This lead me to take it that British optics were the best the Allies had during WW2 (at least, until perhaps the Soviets took-over any German factories in 45). I recollect anecdotal stuff that suggested that though German optics were technically superior they were also more sensitive and more easily mucked up by vibration and gun action than Allied tanks but I've never seen anything definitive.

I wonder if some confusion comes in because of the longer period and far greater selection of British tanks? Certainly, some early-to-mid-war tanks could have been rushed and the make and qualities of optics may have been variable. Same could probably be said of Russian stuff. And for all other armies and tank models, optical capability and quality probably never stood entirely still, so perhaps veteran's opinions and specific academic references, or modern re-evaluations of accepted WW2 wisdom based on specific one-off museum examples, now offer too narrow a view-point and should be treated with caution?

There's too little on-line, and I don't have the will to search through a hundred or more WW2 books in my attic to seek a point which may not be definitive enough anyway, but I did read one good essay on the subject here: http://www.weaponsofwwii.com/forum/viewtopic.php?t=2296

[PzKpfw 1]

Heh the mother of all optic discussions already took place here years ago, do a archive search on optics. I douby any of the old timers left want that opened again, anymore then they'd want the 88 lacks punch thread opened .

Regards, John Waters

[John Kettler]

ArgusEye,

I had a good post put together yesterday, but it somehow got cybernetically "eaten" when I hit the Post Reply button. Shall therefore recap. but first...

PzKpfw1 beat me to the punch in referring you to the very hairy and groggy discussions of optics which preceded CMBB. We really got into it. Also, if you collected optics, did you ever get any goodies from Edmund Scientific? They had U.S. tank gunsights, visions blocks and a whole lot more.

I loved the correction you issued on KE impact phenomenology, and I take the point you made to me. Am curious, though as to the situation with the sIG 33. Throwing an 84 lb. HE shell at 790 fps (basically, .45 ACP velocity), I'd think it would be pretty disruptive--before the 18.5 lbs of pressed TNT filler went off, with the kinds of effects you indicated.

http://www.lonesentry.com/manuals/german-infantry-weapons/sig33-15-cm-heavy-infantry-howitzer.html

Yet, the Germans fielded a gigantic shaped charge stick bomb for it, which strongly suggests the Germans didn't find even that combination of KE and explosive charge adequate.

http://www.afv-news.com/2010/05/afv-club-sig33-15cm/

So, what's your assessment of this issue?

PzKpfw1,

You mean this guy, Joseph Backofen, the man I consider the dean of shaped charge warheads.

www.dtic.mil/ndia/2011ballistics/11778.pdf

Back in the 1980s, I read his two part? series on same in ARMOR magazine and was simply blown away by his page and a half of comprehensive footnotes, which were a graduate level course in shaped charge history and technology. Later, he went to work for the CIA and was the MAN there on shaped charge and SFF (Self-Forging Fragment) technologies. In fact, he's the guy who briefed us on how far we were behind the Russians, to include the shocking vulnerability of the brand new M1 to an obsolete Russian HEAT round for the puny PT-76!

Regards,

John Kettler

[PzKpfw 1]

Yes John, thats him. I agree his work on SC was great. Unfourtently i lost the Armor articles. His KE article was the best i have read to date. I cannot use the link, i'm on my sons Xbox, he has his laptop at school, so i'll have to wait till he gets home to access the link.

Thankfully i can plug a keyboard into this, i cant use that controler thingamijig for beans LOL.

Regards, John Waters

[ArgusEye]

The Stielgranate 42 for the 15cm sIG 33 was meant as a more-or-less daisycutter weapon, to obliterate cover, mines or wire [and basically anything else]. The HC round was a normal projectile. The sIG 33 was never meant to go into combat against tanks, it was supposed to be held behind the lines. Of course, in practice it was sometimes moved up to the front lines for some direct fire (or, in France, dropped off a cliff onto a fortified position), but this was against doctrine.

When you look at HE shells hitting tanks, you should first appreciate what incredibly tough stuff armour steel is. The stuff is hard but tough, and if you ever get the chance, try twisting or bending some of it. You'll see why it can keep stuff out. I once had the opportunity to play with it, and it bewildered me even though I'd seen the numbers involved.

Mr. Backofen seems to have a pretty shrewd idea of hollow charge weapons indeed. It is still a field in active development, with two main directions: the Israeli and American military wanting greater perfection, and the rest of the world wanting more bang out of primitive weapons. I'd love to read these articles in ARMOR magazine you speak of.

Even though I tried, I've failed to find a mother-of-all optics discussion thus far. I found some stuff, but it didn't go much in-depth.

The Soviet Tsh-1~ series of gun sights is very similar to the German TZF-5 and earlier gun sights in optical construction. Mainly the mounting and housing are different. And, of course, the lens quality. Not that strange, since they stem from an era of Nazi-Commie design cooperation.

I had only four gun sights myself, but if you collect weird stuff you come into contact with the real nuts who have complete collections, and I spent some time playing with those. There are a lot of parameters that define an optical system, and they all boil down to making a good image. If you keep that in mind, it's really simple to grade their quality. To give an example:

From my house it's 2700 meters to a church belltower. I can see the clock with the naked eye, and I can read the time. If I use the Sherman M71G spotting telescope, I can easily read the time, and make out that the numbers are Roman numerals. Using the Soviet Tsh-16, I can see the numerals clearly and read them, together with the motto on the lower dial. With the German SflZ1a I can additionally see some brilliant white points on four locations of the dial, which turn out (on closer inspection) to be the mounting screws.

But by day the difference is not greatly pronounced. When light fails, it becomes more important. I visited a collector who had more stuff, and that evening I pointed most of his collection at a road. The road was ~2000 meters away, partly obscured by trees and brush on the shoulder. The sun was down, twilight past, and the moon was three quarters and behind me.

With a sight from a Semovente I couldn't even find the horizon. It was like the lens cap was on.

With the British scope (from a Comet) I could find the horizon, but every time a car passed, there were a lot of internal reflections from the headlights, and I couldn't tell if it was a car coming from the left or from the right. The whole thing was a bit finicky, and one error could put it out of proper alignment, so maybe I could have gotten a better picture, but I severely doubt anything could have improved the parasitic reflections.

I tried an American scope, which was better, but still only showed lights moving along a barely-perceptible horizon.

A French sight (from an AT gun, not a tank though) was simple and it didn't magnify much, but it did show a vague car-shape behind every set of headlights, and you could make out if they were trucks or cars.

The jump in quality when I then picked up a Tsh-15 was palpable, because I could make out the model of each car, and distinguish the trees separately, also when there was no car behind them.

Then a TZF-5, which didn't show a lot more than the Tsh-15 had done, but it was easier on the eye due to more light let through, and one could actually distinguish the reticle against the dark background, which none of the others allowed.

All of this boils down to differences in lens quality, no matter what magnification or field of view is made. Great lens quality makes clearer image. And if your life depends on you spotting whether or not a branch two kilometers away has a muzzle brake, you want a good picture.