Saturday, 2 March 2013

Penetration

If you read the World of Tanks forums, odds are you've seen this penetration table. Overlord even talked about it on his blog. For those unfamiliar with it, let me give you a quick translation. 

The column on the left is distance to target in meters. The first row lists the guns: "45 mm tank gun model 1938 on tank T-70", "57 mm gun ZiS-4 on tank T-34", "76 mm gun F-34 on tank T-34 and ZiS-3 on SU-76", "85 mm gun D-5 on SPG SU-85 and S-53 on tank T-34-85", "85 mm gun of increased power, experimental", "100 mm gun on SPG SU-100", "122 mm gun D-25 on tank IS and SPG ISU-122", "152 mm howitzer on SPG ISU-152" (ML-20), "122 mm gun of increased power OBM-50, experimental" (BL-9), "152 mm gun of increased power OBM-53, experimental" (BL-8, BL-10), "57 mm English gun" (6 pounder), "75 mm American gun on tank M3 Lee" (M2 tank gun), "50 mm gun Model 1938 on tank PzIII", "75 mm gun Model 1940 on tank PzIV", "75 mm gun Model 1942 on tank Panther", "88 mm gun on tank Tiger", "88 mm gun on SPG Ferdinand". 

The V0 value indicates the muzzle velocity of the shell. Under each gun name, there are two columns: one for an armour plate angled at 60 degrees from horizontal and one for an armour plate angled 90 degrees from horizontal. When two values are shown in one box, the numerator is the performance of a caliber AP shell, the denominator is the performance of a subcaliber AP shell. 

CAMD RF 81-12038-303

If you've seen it before, you also have heard criticism aimed its way. "Propaganda!" some people cry. "The 8.8L/71 penetrated 203 mm at 100 meters, not 168! This document is not to be trusted!"

They are wrong about the propaganda bit, as this was a classified internal document, used by engineers to analyze the required armour and firepower for future tanks. It would be pretty foolish to falsify these numbers. Besides, a dense table of data isn't exactly the best for propaganda material.

However, the 8.8L/71 did penetrate 203 mm of armour... when the Germans tested it. German penetration testing standards were different from the Soviets'. German penetration tests were performed with specially selected shells, against armour angled at 30 degrees. If a shell could penetrate the effective armour thickness 50% of the time (several times in a row, depending on the shell caliber), that penetration is recorded as how much that shell can penetrate.

Obviously, the Soviets didn't get courtesy shipments of special testing ammo, so they used whatever was captured along with German tanks. Therefore, these tests give a better indication of how a tank would perform on the battlefield. The Soviets had two penetration standards. When only one penetration value is shown, 75% of the shell fragments end up behind the armour plate. When two penetration values are shown, the two values are for 20% penetration (possible penetration) and 80% penetration (guaranteed penetration). So, as you can see, according to this data, while the 8.8L/71 could penetrate 203 mm of armour using special shells with 50% probability, it could only penetrate 168 mm using regular shells with 75% probability.

This document is very interesting, because it brings together most common guns of WWII (regrettably, some interesting ones are missing, like the 17 pounder or the Sherman's 76 mm gun) under the same testing conditions. This makes the comparison between the various guns much easier than having to pick through various sources, and then tring to figure out all the different test conditions.

Now, time to do some comparisons! You may have read a lot about the unprecedentedly devastating power of the Tiger's gun. However, it penetrates 120 mm at most. This is definitely high for WWII, but similar performance is reached by the Soviet 57mm ZiS-4, that was mounted on some T-34s since 1941, as well as the 85mm guns from the SU-85 and T-34-85. With APCR, even the ordinary T-34's 76 mm gun surpasses the Tiger in penetration (albeit at the expense of accuracy).

The Tiger's successor, the Tiger II, reaches better results with the 8.8L/71 gun, 168 mm. However, the D-25 gun on the IS-2 (which I compared to the 88 mm guns before) achieves nearly as much penetration, and the D-10T gun on the SU-100 (also tested on the T-34-85) surpasses it.

The Panther's long 75 mm gun also has very good penetration, and is comparable to the experimental 85 mm gun. Of course, the experimental OBM-50 and OBM-53 surpass all other guns on this table with huge penetrations of 230 mm and 244 mm, respectively. This would have been enough to take out a Maus tank, if Germany had ever sent any into battle.

In conclusion, the myth of superior German tank guns is, yet again, proven false.

See more penetration values in Penetration, part 2.

43 comments:

  1. "It would be pretty foolish to falsify these numbers."

    Yet you reiterate the claim that Germans used special test-grade ammo that, seemingly, produces much higher penetration values compared to standard ammo. Thus, in effect, Germans were out to lie to themselves. Can you clarify and preferably give source that explains this "special ammo" practice?

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    1. Not special ammo per se, but the highest quality of shell lots, as opposed to average, or a randomly selected spread. This practice is described in "German Steel Armour Piercing Projectiles and Theory of Penetration". It's a nice report, with lots of details about German AP tests, I highly suggest reading it if you can find it.

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    2. So basically you typed out a lie more or less.

      ZeZergling reports that the rounds are "of known quality"

      Didn't the Germans also have a round with almost the exact same results as the russians for the 88mm L/71 cannon? Does the report detail the wear of the cannon?

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    3. I don't know who or what "ZeZergling" is or why you think it's a reputable source.

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    4. Zergling* WOT forum user. Apparently he/she has done some extensive work on the EU server; not quite as extensive as yours as far as i am aware.

      I was wondering if you could confirm that particular statement for me.

      Now could you please answer my question?

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    5. No, the report does not contain details about the wear of the cannon.

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    6. So that might could mean a slightly lower number than otherwise achievable. Perhaps +5% at the high end? So approx ~176mm of penetration? Though such a margin would not be of particularly great concern I would imagine.

      Now I was wondering if it would be feasible to mount a 120mm L/56 cannon onto a 35-40 metric ton medium tank using WWII era technological developments.

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  2. Thanks for the source. But having read through testing criteria, I get very little from shell selection process. Regarding calibrating plates for testing:

    "5.2 Calibration of Plate
    This did not appear to be a universal practice and was carried out only in very important trials. They did not make special standard or calibration shell; but selected a lot from a good maker such as Stock of Berlin."

    And that's it. Calibration shells were from ordinary production runs (and however you want to interpret word "selected"). No word how they chose shells for more mundane tests.

    So unless the practice of cherry picking shells is much better documented somewhere else, it should be considered a myth.

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  3. Actually acording to this test the panzer 4 can pierce the frontal hull armour on the t34 and the t34/85 at 1000 m firing at a 90 degree angle and at 500 m at a 60 angle degree, on the other hand the t 34 armed with the 76 mm f34 gun has problem piercing the 80 mm hull armour on the panzer 4 g to j even when firing at 100 m and at a 90 degree angle, sorry for my bad grammar im yet to finnish my english course.Also i would like to see a soviet report about the 7.5 kwk 40 vs t 34 and m4 sheman if you have time for that.

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    1. Regrettably, I do not have a report on tests with those guns. I'm keeping an eye out, this is a topic of interest to me as well.

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    2. No, according to the chart T34-76's 76mm (F34, 41.5 caliber) can penetrate 104mm armor from 500 m at 90 degree using the round with over 1000m/s muzzle velocity (which I suspect to be the BR-350P ACPR). So they do have a chance of penetrating later version of the Panzer IV hulls with 80mm armor as you mentioned. But not very reliablely.

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    3. Yes but during the battle of kursk soviet tanks where not issued with apcr rounds, anti tanks artillery position yes, so if a t 34 encountered with a panzer 4 g it would have problems

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  4. I will be waiting and also i would like a history section about the panzer 4, given the fact that this tank was germany most numerous tank after the battle of kursk its necessary to have a report about it to understand the nature of tank warfare in the eastern front.

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  5. The original document contains a K value. Which is used in calculating penetration performance for guns with comparable ammunition quality/type. If you have penetration data obtained from actual testing, you can use that to calculate performance for other guns (different calibre, velocity).

    The German penetration values are most likely the result of calculations using inferior Soviet ammunition performance for Soviet guns.

    No offence, but if you take the data of a single source over dozens of others showing different data to draw this conclusions, "In conclusion, the myth of superior German tank guns is, yet again, proven false.", you can hardly be considered objective.

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    1. You can look at the practical penetration tests I provide, they confirm this. These numbers wouldn't be used by engineers if they didn't reflect reality.

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    2. Actually Sherman with APCBC rounds could penetrate late model Panzer IV from 900 meters, it was normal APHE rounds that had problem.

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  6. I think why people go "ermagaud Russian propoganda! 88mm L71 had 202mm penetration at 100m!" is because they do not consider ammo types. When people usually quote that 202mm at 100m it is referring to the Pzgr 39/43. From searching on the internet, supposedly this table was made at the end of 1943. Pzgr 39/43 was not in service by then, and during Kursk (when I suppose the largest haul of captured long 88mm ammunition was made), Pzgr 39/1 had accuracy issues and hence was not common, and thus the most common round used by the Pak 43 in 1943 was Pzgr, which is probably the ammunition used in this table..

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  7. about 88L71 gun penetration.. russians also tested that very same cannon themselfs at kubinka. against tiger II turret. it was only gun which penetrated its front armor, as well, round also penetrated the back of the turret as well. as i count right, its 230mm armor total, which few meter of space between the plates as well, so its really a spaced armor as well. so, how can it penetrate so much? ;)

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    1. I have the entire trials on this very site. The KwK 43 was most definitely not the only gun that penetrated the front of the tank, nor was it the only one that tore apart the turret. http://tankarchives.blogspot.ca/2013/03/is-2-vs-german-big-cats.html

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    2. it was only which did penetrate turret front AND rear as well.
      its shot 25 in the pictures. and, i think you do not have complete test results here. they are also removed totally from battlefront.ru site as well, even if google does lead you to it, or russian version of it. its removed/modified hard.

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    3. also there isnt info about that test, but modified one. it wasnt complete test you had there. majority of it is missing

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  8. also, that site isnt anymore in internet. it was with name "was king tiger really a king" , tests in kubinka, with lots of pictures and all that. now there is no more that site, but others, with no such data anymore, or photos. it might be there in russian language still..

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  9. http://photo.sbanzu.com/album/photos_m/36785_1025689_959d2.jpg

    this picture as well is missing from that ORIGINAL test that was there..

    and many others, as well much of text too. now we have only modified fragments of that test left.. like, KT:s front hull was able to penetrated by 122mm cannon from 1000m or something. which was true, when hit at joint between low and upper armor glacis.. but not possible when hit directly mid of glacis plate.. now you see these "modern" versions tellin that it was possible to be penetrated everywhere from front at that distance as well. that hit in the pic, #25 is hit from king tigers own 88L71 cannon ap shot. penetrated front turret armor, like did 122mm too with ap. but 122 didnt penetrate also rear armor of the turret, which 88mm did also penetrate. that tells that there is AT LEAST 230mm penetration for kt AP ammo. but count in that the shell first penetrated 150mm steel, losing kinetic energy, flying position, and parts of the grenade from initial penetration.. still hit the 80mm armor plate and penetrated it after few meters of empty space..

    so penetration power of 88 on 90 degree plate is at minimum of 230mm, more likely way over 300mm of armor at close range, 90 degrees.

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  10. tiger was able to penetrate T34 frontally at 800m distance (45mm front armor at 30 degree angle) thats 135mm armor at line of sight.. and that table tells that tiger was able to penetrate 120mm armor at 100m distance at 90 degree hit..

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  11. This table is wrong ,according to this table the t 34 with apcr could pierce the frontal armour of the the tiger at 400 meters and in real life it couldnt, and also acording to this table the panzer 3 firing apcr rounds could pierce the t 34 hull while in real life it coudnt

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    1. And that is why penetration numbers are only an approximation of whether tank A can penetrate tank B at some range. To be sure, you have to test.

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    2. What Peter said. For one thing, the table doesn't take into account armor overmatching nor shattergap with APCR.

      Heck, US M-36 tank crews complained when they saw their 90 mm HVAP rounds shatter against the glacis of Panthers when they should be able to penetration well over 200 mm of armor.

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  12. This document alone is of questionable value if further details are not given, such as; where and when did the tests take place; what ammunition was used for the various guns; what testing plates were used; etc.
    Without this and coupled with Soviet and German tests, the validity of these figures are in question. For example, both the 100mm BS-3 and the 8,8cm L/71 seemed to have no problem penetrating the frontal turret armor of the Tiger II, yet according to this guide (which gives us no detail on the testing process and materials) the given figures for the penetration at the distances the guns penetrated the turret, are considerably short of what would be needed to penetrate the Tiger II. Yet, both of them did in fact achieve this. So then where are these figures coming from?
    Further, while the 203mm of penetration at 100m against 30 degree plate, is basically an idealized number for the 88 L/71, the disparity between 203mm and 137mm is far too large of a number to just blindly accept. I have no doubts the 8,8 L/71 did not penetrate 203mm in the field, however to suggest it would typically achieve only around 137mm, is suspect.
    Going further with this, the 122 D-25 in some Soviet reports shows a penetration ability of roughly 210mm at 100m against 90 degree plate, and 170mm at 1400m. The 170mm at 1400m, coincides more accurately with the "IS-2 vs Ferdinand" pictures, and it makes sense as to why one round of the 122mm did little to the Ferdinands armor (150mm to 180mm portion), while the second round managed a partial or half penetration.
    According to this table though, the 122mm would have typically lacked the ability to achieve a partial penetration at a range of 1400m.
    Is there any further information on this document which would shed some light on the disparity of Soviet, German, and American tests and the figures reported here? Even Soviet testing and figures show a greater penetration ability of various rounds, relative to this document.

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    1. Did you miss the part where every nation has a different testing standard? The D-25 achieves north of 200 mm of penetration under American standards, for instance.

      The Ferdinand's front 200 mm (100+100) is worlds apart from 200 solid mm of Soviet test plate.

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    2. There is a wide discrepancy in penetration results from testing protocols, even when the protocols are similar. John Salt compiled a list from various sources; for the German 75 mm Pak 40, tested a zillion times by all combatants, the test results varied something like 17 % even throwing out the highest and lowest results.

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  13. Did you miss what I said about other Soviet testing achieving much higher penetration figures on the 122 D-25 than what this table shows?

    Two separate Soviet figures showing two separate numbers.

    Further, your comment on the Ferdinand armor being worlds apart from Soviet test plate, is useless to this discussion if you do not provide links or references to the Soviet test plate in this article.

    Again, what test plates did the Soviets use for this values found in this table? Definitively.




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    1. What conflicting Soviet data do you have? Differences could be due to using flat/pointed AP shells. As for the test armour, I don't have its exact composition, but it would be a high hardness RHA plate.

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  14. This article just proves that the author does not know what he is talking about. 50% for the German's testing? That is incorrect and if anything, the German testing required 5 or more COMPLETE penetrations, and ALSO in a condition to detonate the HE filler! The Soviets, with AP and no cap, were counting chunks that made it through in mangled condition.

    Thanks for the info. But this guy has a Pro-Soviet bent and ruins his own website!

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    1. As a logical proposition, "5 complete penetrations" is not inconsistent with "50% statistical chance of penetration". If the round has any ability to penetrate the armor in complete condition at all, as long as you shoot enough eventually you'd get 5.

      As a general proposal, when you have two organizations testing the same gun and one comes up with a significantly lower penetration value than the other under similar "coarse-print" situation (range and impact angle), the most obvious hypothesis is that they were testing to a overall tougher "fine-print" standard (tougher steel or higher incidence of penetration or more complete penetration), so Peter at least has a prima facie case. It is the inverse that would take some real effort to prove.

      BTW, are you the same Anonymous who comes and spits random stuff every once in a while? I really appreciate your effort to present the other side, but you'd be a lot more convincing if you can decide on an net identity that's not "Anonymous" and make some real effort (e.g. links) to substantiate your assertions. Right now, you just look like a Germanonphiilic troll.

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  15. @arkhangelsk: German penetration criteria for 7.5 cm, 8.8 cm and 12.8 cm stated 5 consecutive successful penetrations, where successful meant 'in a condition fit to burst', e.g. explosive filler intact). Consecutive being the key word here. If any failed to penetrate, the test would start anew.

    As for the document presented here, that K value clearly indicates calculated penetration. German performance stated is what these guns would (theoretically) penetrate when using Soviet type and quality ammunition. THAT's what can be derived.

    Soviet criteria can be stated in several ways. There's Initial Penetration (20% probability 75% of shell mass behind the armor) and Certified Penetration (80% probability of 75% shell mass behind armor). Usually, when only one figure is shows it's the averaged result. Difference between IP and CP is only 11 - 18% roughly (depending on impact angle).

    Even if Soviet criteria is tougher than German one, it would be only a couple of percent.

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  16. Soviet criteria is not tougher.

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  17. the sovjets used also special shells when testing the penetration effects of their guns. It was common. Didn´t you know that?

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    1. I haven't read anything to suggest this. Special shells (with an increased powder load) were only used to test the reliability of guns by simulating the stress of hundreds of shots with only a few.

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  18. "Germans used special shells to falsify their own testing data"


    Nice try you Commieboo. German tests are in line with western assessments. What you don't understand is that all data in this table in regards to german guns are based on equations, not on real life trials. And yet you insist on making that absolute asspull about some "special shells" with no sources to back it up whatsoever.

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    1. Who said anything about "falsify"? It's a different standard, not a falsification. Also if it's based on equations, why are some guns capped out at certain ranges? Surely nothing is stopping whoever composed the chart from filling out all of it unless they, I don't know, ran out of shells to test with?

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  19. Actually this is a bit of cherry-picking.

    Without knowing how the tests where done AND the quality and hardness of the armour-plate you cannot compare it with other data. And why would the german data be unreliable if they repeated the test several times? Why is it flawed to use a maximum value?

    Then there is the question about after armour effect and effect of impact.

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    1. It's not flawed or unreliable. It's simply a different standard. The vast majority of people don't even know that there are different standards and try to mix and match penetration data recorded by various nations without understanding that the numbers don't represent the same thing.

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