Saturday 11 May 2019

None More Frightening than the Cat

German industry created three armoured vehicles during WWII that had a significant effect on tank building worldwide. The appearance of the Tiger made Allied tanks obsolete. The few Ferdinand SPGs that were built introduced serious changes into the Soviet tank program. The third tank was the Panther, and its influence was comparable to that of the Tiger.

The tank was a quite unpleasant surprise for the Red Army and its allies when it made its debut at Kursk. Despite its deficiencies, the Panther is a good candidate for the best German tank of the war. The Panther was superior to the Tiger in terms of armament and frontal protection, and was made in significantly higher numbers. Many tank designers were looking at the Panther when they were making the next generation of medium and heavy tanks.

Debut on the southern flank

The Pz.Kpfw. Panther Ausf.D was Germany's answer to the T-34. Its production began in January of 1943. However, development began long before the T-34 was encountered, back in 1938.

The mass of the tank that was to replace the PzIII kept growing. Initially, it was slotted into the 20 ton weight class. In the fall of 1941, much to the protest of Reichsminister of Armament Todt, the limit was raised to 30 tons. However, the struggle was futile: in March of 1942, when the VK 30.02(D) and VK30.02(MAN) projects were reviewed, the Panther's weight limit was set at 35 tons. When built in metal, MAN's prototype was even heavier than that.

Due to the changing requirements for protection of the front of the hull and turret, the mass of the new tank was estimated to be 43.4 tons by December of 1942. In practice, the combat mass of the. Panther Ausf.G was 44.8 tons, at the level of heavy tanks. The Panther ended up being twice as heavy as the PzIII.

Panther Ausf.D tanks lost by Grossdeutschland division near Karachev, August 1943. The vehicle in the background was likely disabled by a mine, the vehicle in the front was destroyed by its own crew.

The increase in mass without a revision to the suspension and drive train did not go unpunished. MAN created a progressive tank, but it had a large spectrum of design flaws. This was because of the ever-growing requirements for protection. The Panther's chassis had completely exhausted any reserve for modernization before it even entered production. This did not seem like a problem in early 1943, but later it turned out that the Panther's chassis could not bear an increase in protection or firepower.

The overloaded chassis had a significant effect on reliability. Frequent breakdowns were a headache for German engineers and tankers. Reliability reached an acceptable level by the fall of 1943, but issues cropped up after that as well.

This tank was captured nearly intact. Either the engine or the gearbox broke down. An attempt at an evacuation was made, but the tank was abandoned.

The Panther's debut took place on the southern flank of the Kursk salient. The Panther's issues with reliability combined with the Red Army's well organized defenses. At the start of the German offensive, the 10th Tank Brigade had 200 Panther Ausf.D tanks. By 8 am on July 5th, 16 had broken down. After two days of fighting, less than a quarter were still running. By the evening of July 7th there were only 7 combat ready tanks in the brigade. In later fighting the number of functional Panthers was between 25 and 45 units.

The heavy losses were in part due to improper use of the tank. The Panther had a very tough front, but the sides were no problem at all for 76 mm guns or higher. The Panthers took heavy losses from flanking fire. There were cases of Panthers being knocked out by even lighter weapons. In one of the battles in the evening of July 5th, a group of 7 Lend Lease M3 light tanks managed to knock out 5 Panthers, losing only 2 of their own. Many new tanks were lost for technical reasons. The engine and suspension were the weakest links. By July 21st, out of 200 tanks the 10th Tank Brigade initially had, 41 were capable of battle. 85 were in need of repairs, 16 were shipped back to the factory, and 58 were lost irreparably.

Panthers managed to deal serious damage to the 1st Tank Army of Lieutenant General M.E. Katukov. The widespread damage to the suspensions of German tanks is largely due to the work of Soviet sappers. It's hard to call the Panthers' debut a failure. Despite their unfinished state, the Panther proved that it can deliver a powerful blow to the enemy in favourable conditions.

A medium tank with the mass of a heavy

Soviet intelligence learned that the Germans were receiving a new tank in May of 1943. However, the initial information was vague. One of the intelligence summaries for May of 1943 mentions:
"...a super-powerful "Panda-S" type tank with a high speed and more powerful armour and armament than the Tiger"
The first more or less legitimate information on the Panther was obtained from the British on July 9th, 1943, when the Battle of Kursk was already underway. However, it arrived before information about the Panthers came in from the front lines. Even in the summary composed on July 20th, 1943, the Ferdinand is already present, but not the Panther.

The first intelligence information about the Panther. It came to the USSR from Britain.

Study of German tanks used in Operation Citadel began on July 20th, only a week after the Red Army's counteroffensive. Out of 31 Panthers that were examined, 22 were knocked out. All of them were penetrated in the side or rear armour. No penetrations of the front were discovered, which was unfortunate news. A captured tank with the turret number 441 was shot up right on the battlefield. The result was the same: the 76 mm F-34 gun could not penetrate the front armour.

Soviet documents called the Panther a heavy tank from the very beginning, due to its high mass. The British also classified the Panther as heavy. One of the captured Panthers (turret number 433) was sent to them.

Tank #824, NIBT proving grounds, August 1943.

At least two entirely intact vehicles were sent to trials: #824 and #732. Three more tanks that were knocked out, R01 (a commander's tank), 445, and 535, were used for penetration trials. At least two more tanks (#521 and #745) were sent to an exhibition of trophies in the Culture and Leisure Park in Moscow. Tank factories also received captured Panthers.

The position of the turret in the center of the hull made the Panther a more stable firing platform. However, this layout resulted in a significant increase in size and mass.

Tank #824 was used for mobility trials. The same vehicle was studied at the NIBT proving grounds after August of 1943. The tank was captured on July 17th near Novoselovka village by tankers of the 3rd Mechanized Corps, commanded by Major General S.M. Krivoshein. The tank's odometer read 452 km travelled, not an insignificant distance for such an unreliable tank.

The joint of the front plate is visible.

It turns out that the captured vehicle could operate on Soviet B-70 gasoline. Mobility trials began on August 8th and finished on October 5th, 1943. Over this time, the tank travelled 58 km on a highway and 162 km on dirt roads. Its engine ran for 13.9 hours. Such a small amount of driving is explained by the tank's low reliability. The tank had to be towed back to the proving grounds thrice, which took up another 36 km. All this while the tank was driving in dry weather and without ammunition.

The driver's vision slit and radio operator's gun port are open.

The testers managed to accelerate the tank to 50 kph. They remarked on the good maneuverability and fortunate design of the planetary turning mechanism with a servo drive. Average speed on a highway was 35 kph. Issues arose when driving on dirt roads, where the tank broke often. Because of this, the average moving speed was 15.8 kph, but the average technical speed was 11.4 kph.

12 breakdowns occurred during the trials. The least reliable component was the engine, which was deemed unfinished. The Germans themselves admitted this drawback. Guderian, the general inspector of the German tank forces, admitted that the Panther's engine only became capable of driving for 1000 km in the fall of 1943. Soviet testers deemed the Panther less reliable than the PzIII or PzIV.

The captured tank had a non-standard toolbox and wading equipment installed.

The NIBT proving grounds staff classified the tank has heavy, and therefore compared it to the heavy IS-2 tank. The mass of the IS-2 was greater than the Panther's by one ton. It surpassed the Panther in size only in total length. The length of the hull, however, was 130 mm longer than the IS-2, it was also 360 mm wider and 180 mm taller. The ground pressure of the German tank was higher.

The German tank surpassed the IS-2 in power to weight ratio, but there was a downsize. The Panther required 595 L per 100 km to drive on a dirt road, while even on a snow covered dirt road the IS-2 required only 440 L per 100 km.

Testers mentioned that there was not a significant difference in speed between the IS-2 and Panther. German documents confirm this. The claimed average speed of the Panther while driving on dirt roads is 20 kph, while the IS-2's was 18 kph. The difference was more obvious on the highway. The IS-2 had an average speed of 27 kph, 8 kph lower than the German tank's.

The big rear of the tank made an excellent target.

The 75 mm KwK 42 L/70 received high praise at the proving grounds. A muzzle velocity of 1000 m/s made it dangerous for even the IS-2. Practice showed that it was even more dangerous than the 88 mm KwK 36 gun used on the Tiger. The Panther also had a subcaliber armour piercing shell with high penetration. Testers expected German subcaliber ammunition to be effective at 500-600 meters in older guns, but in the Panther it remained useful out to 2 kilometers. Due to good placement of aiming mechanisms, good sight, and electric firing mechanism, the rate of fire of the Panther reached 6-8 RPM.

The Panther's fighting compartment was fairly cramped.

Testers evaluated the gunner's seat highly, as it allowed him to work normally. However, he only had the telescopic sight to look through, and had to rely on the commander's orders when shifting fire. The commander did not fare as well. On one hand, he had a cupola, which permitted him all-round vision. On the other hand, the visibility was worse than from the PzIII. The greatest increase in dead zones was in the front and to the right, to 16-18 meters. The commander's station became cramped, which limited his movement. In practice, he could not nothing but observe the battlefield and direct the crew.

Visibility from the Panther. The tank proved inferior to the PzIII and PzIV in this respect.

The loader was even less lucky. He had no observation devices at all. The gun could only quickly be reloaded from the ready racks. One of them fit 3 rounds and was placed behind the loader. A second 3 round rack was installed on the floor of the fighting compartment. The third, fitting 18 rounds, was in the sponson. Significant issues arose when using any other ammunition racks. The main racks, located along the perimeter of the fighting compartment and in the sponsons, were only accessible if the turret was turned in a certain way. Some of the ammunition was only accessible with the aid of other crew members.

Ammunition located in the tank. Only about one third was accessible to the loader with the turret turned forward.

In general, the fighting compartment was worse than on the PzIII. The turret was bigger than on the PzIII, but was very narrow, and had to fit in a sizeable turret basket and much larger gun. The tank ended up significantly larger than its predecessor, but more cramped.

The visibility suffered as well. Only the commander could observe the battlefield properly, the gunner and loader didn't even have vision slits. The tank was inferior in visibility, significantly so, to even Soviet vehicles. This explains the many case where Panthers were knocked out from the flanks. Instead of three pairs of eyes, only one could observe the battlefield.

Drivetrain and dimension diagram.

The suspension received a high grade. Testers pointed out the good design of suspension elements, which, in their opinion, were well laid out. The centralized lubrication system was pointed out as desirable on domestic designs. The torsion bar suspension with two parallel torsion bars per road wheel was also commended. According to the testers, this kind of suspension provided for smooth travel, providing the torsion bars were tough enough.

A diagram of the suspension that impressed Soviet testers.

The Panther received a high overall grade. Soviet testers considered the vehicle a tank destroyer, capable of fighting armoured targets from long distances. There were good reasons for this evaluation: good frontal protection and the location of observation devices. The power to weight ratio, smooth suspension, and powerful armament were listed as advantages of the tank.

Tendency to ricochet

Soviet specialists paid close attention to the design of the German tank's hull. The thickness and slope of the armour plates set it apart from its predecessors. Even though the Panther's layout was significantly different from that of the T-34, it was clear that the Soviet medium tank was an inspiration.

Due to the placement of the transmission in the front of the hull, it ended up long and tall. The hull was 20 cm taller and a meter longer than on the T-34.

Turret and hull armour diagram. A number of values are overestimated by 5 mm.

The front of tanks was better protected than their sides and rear almost since the inception of tanks. By 1941, the increase in the thickness of side armour on German tanks stopped. The standard was 30 mm. On the PzIII the front armour was 50 mm thick by this point, while the PzIV had 80 mm by the fall of 1942. Meanwhile the thickness of the turret armour was still only 50 mm.

The new German tank had a much greater difference in protection. The upper front plate was 80 mm thick, the lower was 60 mm thick, both at an angle of 35 degrees. This radically increased the protection of the hull. The thickness of the sides grew insignificantly to 40 mm. They were now placed at an angle of 50 degrees. Theoretically, this offered protection from Soviet 45 mm guns. However, production of 45 mm guns with a 69 caliber barrel began in 1942. Allied anti-tank gunners chiefly used 57-76 mm guns, which did not have any issues with armour of this thickness, even at an angle.

Joints used in production of the Panther hull and turret.

The joints used in production of the Panther were of great interest to Soviet specialists. Previously, German tanks had their plates joined with butt welding. The Panther's plates were joined with an interlocking tenon joint. This was not revolutionary. Several factories that made T-34 tanks used this joint. However, the T-34 used a different tenon, and only in some places. The Panther had this joint in most connections on the hull and turret.

The tenon joint increased the strength of welded connections. After studying the German method, these joints were implemented in a number of Soviet tanks. IS-2 tanks with a straightened front plate used this joint, as well as the T-44.

Penetrations made by subcaliber ammunition fired from the 45 mm gun at 100 meters.

Naturally, the first thing that the GBTU cared about was what could be used to destroy the new German beast. Several tanks were shot up at the NIBT proving grounds between December 1st and 14th, 1943. The first tank to fire was a T-70. The testers did not even try the front armour, but fired at the sides. The results were interesting: the sloped side armour could not be penetrated from even 100 meters, but the flat side could be penetrated from 500 meters. Panthers were supposed to have this armour covered by 5 mm spaced armour, but it was often missing. The 45 mm gun could penetrate the rear from 300 meters and the side of the turret from 400 meters.

The tank was also fired upon by subcaliber armour piercing shells. The gun mantlet was penetrated from 100 meters. It was cast, which reduced its toughness.

The side armour of the Panther was vulnerable to 57-76 mm guns at a range of up to a kilometer. Combined with poor visibility, this became a leading cause of many losses of Panther tanks to flanking fire.

The 6-pounder gun installed in a Churchill III tank was also not tested against the front armour. The side of the hull and turret could be confidently penetrated by the British gun from 900-1100 meters. The 75 mm M3 gun on the American M4A2 Sherman tank could confidently penetrate the side from 700-900 meters. The Soviet 76 mm F-34 gun could confidently penetrate the side from 1000 meters. 

Impacts from firing at the front armour with an 85 mm D-5 gun. No penetration was achieved at even point blank range.

The D-5 gun used in KV-85, IS-1, and SU-85 vehicles was the first gun used against the Panther's front armour. The results were quite unpleasant. It turned out that the armour was not penetrated from even 100 meters. The sloped front hull caused ricochets. Penetration was only achieved by striking locations weakened by previous hits or by hitting the joint between the upper and lower front plate. However, hits by 85 mm rounds began to destroy the weld seams. It was clear that the idea of replacing the D-5 was a correct one.

Penetration of the front armour from 1400 meters.

The replacement for the D-5T was the 122 mm D-25T gun installed in the IS-2 heavy tank. The first shot from 1400 meters penetrated the armour. These trials gave birth to the myth that the round penetrated the front of the tank and knocked out the rear plate. What really happened was that, when shooting at the side of the turret of tank #535, the shell penetrated the left side and broke off the right armour plate, throwing it backwards by several meters.

The result of hitting the Panther with a 152 mm round fired from the ML-20 gun.

When hit with a 152 mm shell fired from the ML-20 gun installed in an ISU-152 SPG at a distance of 1200 meters, the round ricocheted from the upper front plate, but this did not matter. A 360x470 mm breach was formed in the tank's armour, which was guaranteed to put it out of action. Another tank was hit in the side of the turret. This shot formed a 350x370 mm breach in the side armour. The shell then exploded inside the turret, leading to partial destruction.

The results of these trials show that the Red Army already had measures against the German beast in late 1943. Nevertheless, Soviet specialists made the right calls. The 85 mm gun that was proposed to go into the T-34 was not powerful enough to combat the Panther. It was only capable of penetrating the gun mantlet at a range of one kilometer.

Damage to the front of the tank by a 100 mm armour piercing shell fired from the D-10T gun. At 1500 meters a penetration was not achieved, and the gun had to fire from 1200 meters.

One alternative to the D-5 was the 100 mm gun with ballistics of the B-34 naval gun. Two similar weapons, the S-34 (TsAKB) and D-10 (factory #9 design bureau) were developed. The D-10 won the competition. However, trials showed that the front armour of the Panther could only be penetrated from 1200 meters. Shots fired from 1500 meters could not penetrate the armour.

The 122 mm D-25 gun proved superior. The BR-471 sharp tipped armour piercing shell confidently defeated the front of the German tank from 1500-2000 meters (although ricochets were observed at very long range). A blunt tipped BR-471B shell was tested in the summer of 1944, which increased the effective distance to 2500 meters.

Both sides of the front

Panthers began appearing en masse on the Eastern Front in the fall of 1943. The Ausf.D was gradually replaced with the improved Ausf.A. These tanks were put into production in August and appeared on the front lines in the fall. These tanks became truly numerous and caused a number of issues for the advancing Red Army.

Instructions for fighting the Panther tank, fall 1943.

Initially, the protection of the German tank was underestimated. According to instructions issued in the fall of 1943, the Panther was vulnerable to 85 mm guns, and when shooting at the driver and radio operator hatches, to 57 mm guns. In reality, the Panther was a more dangerous enemy than the Tiger, since it had superior front armour and a more powerful gun.

The Panthers ended up being the first enemy of the IS-1 tank. The armour of the IS-1 was built to withstand the 88 mm gun used on the Tiger, but the 75 mm KwK 42 L/70 was more powerful. The IS tank's armour had to be improved, and even late production IS-2's turret was still vulnerable to the Panther's gun.

Tankers received the same reward for destroying a Panther as a Tiger: 500 roubles. Often the Panther and the Tiger would be mixed up in reports. The Panther, however, often fell victim to even light tanks due to its weak side armour.

A manual for using captured Panther tanks, summer 1944.

Scenarios where captured Panthers were used in the Red Army deserve a separate mention. The first such instances were recorded in the fall of 1943, but they were few. For instance, one Panther was briefly included into the ranks of the 59th Tank Regiment, even though very many new German tanks were captured. This was because of the poor reliability of German vehicles, especially the Panther Ausf.D.

The situation improved somewhat with the appearance of captured Panthers Ausf.A, but the opinion regarding the reliability of the Panther remained low until the end of the war. The Red Army completed a successful series of offensives in early 1944, the reward for which was the capture of many trophies, with a large number of Panther Ausf.A tanks among them. Some tanks were repaired on the spot, but most were sent to the repair factory in Kazan. Complaints were made about a lack of optical devices, which were needed to fully restore the tanks. A brief instruction manual for the captured tank was prepared in August of 1944. They were largely based on the reports on the trials of the Panther tank at the NIBT proving grounds.

Panthers from a captured tank company, 62nd Guards Heavy Tank Regiment, August 1944.

Captured Panthers were most widely used in the summer of 1944. For instance, the 51st Independent Motorcycle Regiment had a company of heavy tanks, consisting of 5 Tigers and 2 Panthers. Only one Panther remained by the start of the Lvov-Sandomierz offensive, and even it needed repairs. The tank remained in the condition of "medium repairs" all July, continuing to participate in combat. The situation was not unique. Many units of the 1st Ukrainian Front that used these tanks complained about the Panthers' poor technical condition.

Captured vehicles were also used by the 8th Guards Tank Corps. On August 18th, 3 Panther Ausf.A tanks were captured by the 59th Guards Tank Brigade from the 5th SS Tank Division near Jasienica (Poland). On the next day, the tanks were transferred to the 62nd Guards Heavy Tank Regiment. By that point, the regiment had 11 IS-2 tanks. German tanks were gathered into a company under the command of Junior Lieutenant Sotnikov and received characteristic emblems of the 62nd Guards Heavy Tank Regiment.

Due to their low reliability, Panthers were not used frequently by the Red Army.

Problems with captured Panthers were not only plaguing the Red Army. After the end of the war, a large number of Panther tanks were adopted by the French, who also did not consider them reliable vehicles. Panthers quickly vanished from other armies of the world for the same reason.  The PzIV and StuG 40 did much better comparatively, and fought in all corners of the world until the 1960s.

At the same time, it is not fair to underestimate the Panther. The German tank influenced tank building schools in all countries. For instance, the British Centurion is an analogue of the Panther in many ways. Soviet tank designers also evaluated it highly.


  1. Good article, though I more agreed with an article you previously posted about a Soviet evaluation which concluded "great defensive anti-tank tank, not so good doing other things". Their first employment at Kursk was about the worst possible way to use Panthers--trying to bludgeon your way through prepared infantry defenses, with their weak side armor and an unimpressive HE round.

    In addition, I would say that offensive-minded spirit of German tank doctrine mitigated the usefulness of its most famous weapons systems. You have these ideal defensive weapons, formidable when engaging an enemy at range from ambushes, and yet your doctrine preaches the tactical offensive?

    According to an analysis of the Panther's rounded mantlet by Bird and Livingston, at close ranges only about 10 % of incoming shots will impact at angles of less than 15 degrees (so assume the range of vulnerablity is up to c. 1000 m or less for the 85 mm) and about 15 % more will impact at angles of 20-30 degrees or less (so assume maybe 500 m or less the vulnerable range). 75 % or more will impact at more oblique angles; 51 % will hit at angles of 50 degrees or more. So practically speaking, the Panther's mantlet is a tough target for the 85 mm even at suicidally close ranges, if you use the 50 % criterion. A lucky shot on the smaller flat surfaces around the mantlet on the Panther's turret would penetrate at 1000 meters or more.

    The IS-2's 122 mm gun is way more effective because of overmatching though the figures I calculate aren't quite as optimistic as the ones you cite (though that could be, in reality, the variable and sometimes dubious quality of German armor).

  2. Millen. The reports of the 122mm gun being more effective at penetrating is a two edged sword. 90% of the game is getting the first hit. And am I the only one who thinks the Panther hull was just a tad too tall. When one looks at the video of the loader, he is reaching under the breach to load the 75mm main gun. Plus it would of helped if they extended the rear of the turret like the King Tiger's turret. That would of provided room for a dozen or so easy access ammo.

  3. William Sager: I meant 'way more effective than the 85 mm" when speaking of the 122 mm. The 85 mm would struggle to penetrate the Panther everywhere save the relatively small, flat, areas around the turret, and the lower plate (the latter at c. 500 m).

    The 122 mm by contrast has good chances at c. 1500 meters (more if you assume problematic German armor). If you're talking gun vs armor matchups against the IS-2, even the IS-2 model 1943, while more vulnerable to the Panther than the Tiger I, has a good chance of surviving shots from the Panther outside 1000 meters (assuming German test results, if you assume these are 5 % or more too-optimistic then the limit is more like 700-800 m). So even the IS-2 model 1943 has a range advantage vs the Panther, and it increases with the IS-2 model 1944.

    First shots and hits are important, but it's not just a factor of the rate of fire of the gun and accuracy. Tactics matter too. Crew training and experience matter. One might assume that the Germans would have an advantage here (but then again, the Germans in 1944 and afterwards were putting their fair share of green crews in Panzer brigades under inexperienced officers, witness Arracourt). Another advantage for the IS-2 would be it wouldn't matter if the IS-2 was caught with an HE round loaded in the breech instead of an APHE when it confronted a Panther, as the HE round would also disable about any tank. It does matter for the Panther.

    1. Stewart Millen. To be fair I would take the IS-2 over the Panther with a 122mm, 100mm or even the 85mm. And I always felt that longer range plunging fire from 122mm's countered the sloped armor of even the best tanks.

    2. "The 122 mm by contrast has good chances at c. 1500 meters (more if you assume problematic German armor)."
      When you consider the problematic ballistic test calculations the wartime Russians had you find that they thought the 122mm BR-471 impacted at 710 m/s at 1500m. Post war firing tables have that impact velocity at around 700 meters.

    3. When you consider the problematic ballistic test calculations the wartime Russians had you find that they thought the 122mm BR-471 impacted at 710 m/s at 1500m. Post war firing tables have that impact velocity at around 700 meters.

      Huh, postwar firing tables concocted by whom? (Yes, it makes a difference).

    4. Here is the WWII ballistics.
      Here is post war data. Look it up yourself. Peter had two of the firing tables posted here sometime back.!7Gwy0YzA!1X7pAKfio5SZ_nhyXB62Spbwf0TqK5UJT0v9n1QAe3Q

    5. Well, at least I concur with you on this, given the country of origin (I was thinking you were citing data done by other countries using a very limited sample set, which would be the case with captured Soviet equipment (and even after the Arab-Israeli wars where more would be to be had, could be worn-out Soviet equipment--witness the reference to wear on the guns cited in the report I cited). Your report is in Russian, so I credit that they would avoid those potential issues.

      But that still does not explain the results of both Kubinka tests and combat experience. It's going in the wrong direction, as the Livingston and Bird calculated values don't predict penetrations of the Panther's upper glacis (and, given a 50 % criteria of the angle of impact) of the mantlet, past 1500 meters, even when you thrown in the effect of overmatching, and you wish to argue those values should be even lower still. Nor would Soviet heavy tank doctrine (not just described here on this site but also in David Higgin's book which I have, though I disagree with parts of it) recommend engagement at 2000 meters if the gun wasn't effective at those ranges both at hitting its target and doing damage.

      That leaves one with 'poor German armor' as an explanation. But German armor wasn't universally poor; like most QC problems, it was spotty. There are also reports of the uncapped BR-471 round failing to penetrate the Panther's armor at 700 meters or so, but that could be just slope effect (and the WW2 equipment site shows a high chance of shattering, even though there too that site doesn't appear to have overmatching built in).

    6. On the topic of uneven German armour:

      Short form - one of the three Panthers tested in 20-21 August stood up to the 76 mm and 17pdr just fine, the two others suffered fairly dramatic glacis plate shattering. Wonder if the German crews were aware the actual degree of protection they enjoyed was down to the proverbial luck of the draw and how they felt about that...

  4. In terms of Panther tank armour, I found drawings about Panther tank armour (drawings propably was made during WWII) and I put this drawings on my blog:

    We can see that Panther tank have far worse side armour than front armour, but from other hand, Panther tank uper side armour can stop some projectiles if was horizontally angled.

  5. I said it before in another topic about Panther penetration tests but the performance of the 122mm seems to be overestimated since they used wrong ballistic tables. They estimated range by reducing the charge to a certain velocity which resulted in the wrong penetration ranges. The 100mm is ballisticly superior and can, according to my slope calculator, penetrate the front of a Panther at 1200m, which matches the penetration test.
    However the 122mm would only be able to do so till ~950m (with v0=795m/s).
    The 122mm shell only has around 5.7% more mass per area compared to the 100mm, meaning that it would require around 2.8% less velocity to penetrate the Panther. Since the 122mm is fired at lower velocity the 100mm has the upper hand when it comes to penetration at short and long distances, as well as being a lot easier (=faster) to reload.

    Below 1000m the Panther is an easy target for the 122mm but at long ranges the Panther would have the upper hand. With the poor visibilty and weak side armor the Panther is truely more a long range TD which is honestly a big waste for a 45t vehicle.
    Producing more 30-35t tanks which didn't have so many reliablity problems would have been the better call.

    1. "The 100mm is ballistically superior and can, according to my slope calculator, penetrate the front of a Panther at 1200m, which matches the penetration test."
      There something wrong with that as well. The WWII firing table of the 100mm BR-412 has it at ~810 m/s at 1200m. In reality the updated firing table of 1957 has it only at 710 m/s at that range. 810 m/s would be at a range of ~665 meters.!ubxQwYbY!ejteiojqEsP9y5TPQ3pwT_uDPITDULUZF071pRz6GoY

    2. All we can conclude from what you're posting is that German armor quality was even more 'problematic' than I had supposed, because these guns could indeed penetrate the Panther's armor at 1500 meters when your calculations suggest they could not have. Not just on the turret, where you could assume a lucky near-normal impact angle, but also on the hull.

    3. "because these guns could indeed penetrate the Panther's armor at 1500 meters"


    4. Kubinka test results?

      And yes, these are actual test results, not based on calculations. Nor are they just isolated to Kubinka tests, because reports from the field also confirmed the vulnerability of the Panther to the 122 mm at ranges it shouldn't penetrate (yes, even by the Livingston and Bird figures you want to discredit) even when you calculate the effects of overmatching.

    5. So do you think they drag the tank hulks out to 2000 meters then to 1500 meters then to 1400 meters then etc. meters on the range or do they move the guns back that distance? Then hope they hit the tank from that distance in a useful area?

      How about this. Like KillaKiwi said they modify the propellent charges to get the shell to impact at what their firing table says it will at those ranges and actually position the gun 50 to 100m away from the target so they can place the hit.

    6. Again, you are ignoring the fact that field reports back up the test results. 122 D-25s and A-19s did in fact take out Panthers at that range, and that range was recommended in Soviet heavy tank tactics.

      Testing should predict actual results in combat, and these apparently do.

    7. If memory serves the Germans also soon gave standing orders for tanks (of all sizes) to avoid lingering on hilltops and the like, as the improved observation was not worth the losses from opportunistic 122 mm long-range sniping.

    8. @ Stewart Millen, Where are these field reports?
      That's why I asked for citations. I don't recall any that mention accurate distances.

    9. @Mobius: depending on the test, they do. Most famously, in the Gorohovets trials of the Tiger the shots were fired from a real distance, and the incredibly skilled and valorous ML-20 crew failed to hit the target at all ;)

      If the tests were done at fixed ranges with variable propellant, that is noted in the description of the test.

    10. @Mobius

      Baryatinskiy references these field reports in his book on the IS tanks, but I suppose he isn't good enough for you. (Do you really believe that Soviet tankers can't distinguish between shooting at something at 2500 meters versus 1000 meters? That their sense of range is THAT far off?).

      So how about this?

      "On the morning of April 20th, nine T-34-85 tanks and an AT regiment that arrived to reinforce them were located at Zhivachuv and Podvertse villages. ISU-152 SPGs positioned themselves south of Podverbtse, several kilometers away from the medium tank positions. IS tanks from the 72nd regiment arrived some time later.

      The Germans sent about 70 tanks into battle, supported by infantry. 25 Tigers and 15 PzIVs came at the T-34-85s from Isakow and Oleshi (other accounts say it was only 5 PzIVs, the rest were Marders and StuGs). At the same time, 30 Panthers advanced from Ezhezhan, along the western outskirts of Zhivachuv.

      The group coming from Isakow was fired upon by the T-34s, with no losses. The Tigers turned and drove at the ISU-152s. After a difficult fight, the regiment lost 10 SPGs, trading them for 13 German tanks.

      The Panthers had an even more difficult time. One of the companies hit a minefield, where several tanks were immobilized. T-34-85s and 57 mm AT guns opened fire on this group and had some success, but it is difficult to ascertain how many tanks could be credited to them, since the Germans were about to face the heavy guns of 10 IS tanks that approached Gerasimov and entered the battle.

      The breakthrough regiment, skilfully hiding behind terrain and houses of a nameless farmstead, opened fire at the Germans from *1.5 kilometers*. The IS-2's gun was powerful enough to destroy even well protected Panthers from this distance. The enemy attack stalled, his tanks retreated, and did not return that day. According to German sources, no less than 20 Panthers were lost that day, 15 of those were irreparable. The 72nd regiment lost one IS-2 and another one was knocked out."

      How about that? The IS-2s are engaging the Panthers at 1500 meters, and not just one or two but *20 Panthers* are taken out, 15 of them irreparable losses, all (the article says) backed up by German sources. That's pretty impressive and indicate that the 122 mm had a great chance (not just from flukey lucky hits) to take out the Panther at that range, irregardless of where the shell hit. Something you seem to deny is even possible for it to do.

      What's more, you're reversing cause and effect. The Soviets did start doing the testing with the 122 mm as anti-armor gun and then, after doing what you say are flawed tests, conclude it would be a good anti-tank gun. No, what happened was necessity became the mother of invention--because of dire need during the Battle of Kursk, the Soviets leveled their 122 mm and 152 mm guns at German heavy armor, because their 76.2 guns were found lacking, and found how "whoa!! these things do an awesome job!" as you can see in another post by Peter:

      There are no Panthers here, but some Tigers and Ferdinands, and some of the hits are from 122s.

      In short, the Soviets first found out the 122 mm was a good anti-tank weapon by actual experience, THEN tried to quantify how good by testing.

      Like I said, Peter cites several instructions on the use of IS-2 and ISU regiments, and they have them engaging at ranges you say won't work.

    11. The effectiveness of the A-19 against Tigers was shown in the same trials where the ML-20 missed completely, so it was firing from a real distance. Shot #1 passed through a previously made breach in the front and punched through the rear armour, shot #2 hit the turret with such force that it was displaced from the turret ring, shot #3 ricocheted off the roof but the impact caused severe cracking.

      As a result of these trials, the GABTU requested a tank destroyer made up of the SU-152 chassis and A-19 gun. The IS-2 was only produced a couple of months later.

    12. @Stewart Millen

      I got your mother-of-invention right here.

      There was no 'discovery' of anti-armor ability of the 122mm and 152mm M 1937 at Kursk unless you believe July 1943 comes before May 1943. Because those guns were tested in early May 1943.

    13. @Mobius

      You're referencing an article on using HEAT rounds on 122 mm 1938 *howitzers* (not the 122 mm A-19 corps gun) as a rebuttal? Did the article on the usage of 122 artillery 152 artillery pieces mention HEAT round usage Kursk? (Seem to me they were either AP rounds or HE that wreaked all that havoc).

      For that matter, did the IS-2 carry any HEAT ammo? (It did not, to my knowledge).


      "The first person to suggest arming the JS tank with a gun larger than 85 mm was the Director and Chief Designer of Factory No.100, Zh.Y.Kotin. He realized in August 1943, after studying the results of the Kursk battle, that the most effective anti-tank weapon employed against German Tigers was the Corps 122mm Field Cannon A-19 Model 1931.

      The designers at Factory No.9 came to the same conclusions as Mr. Kotin, and designed the D-2 Heavy Anti-Tank Cannon by marrying the A-19 barrel with the carriage of the Divisional 122mm Howitzer M-30.

      This powerful weapon was ordinarily employed against heavy tanks as an anti tank gun. The barrel of the gun was built into the gun carriage of the M-30 and the resulting gun successfully passed its tests, it became possible to install the A-19 gun in a heavy tank by using recoil-absorbers, elevation mechanism, and other mechanisms from the Experimental 122 mm Tank Howitzer U-11. This was done in a similar fashion to the 85mm guns D-5T and D-5S, but it was also necessary to add a muzzle brake.


      The first example of the A-19 tank gun was ready on November 12, 1943 - the barrel of the D-2 gun was removed from the M-30 gun carriage and installed in the D-5T base after after reducing its diameter. The T-shaped muzzle brake design was borrowed from the D-2 gun. The unusual muzzle brake was intended to reduce the main disadvantage of any muzzle brake: when a shot is fired, a large cloud of dust is kicked up from the ground, revealing the position of the tank. The T-shaped muzzle brake was intended to minimise any dust plumes due to firing.

      The JS-122 (Object No.240) passed the Government tests quickly and successfully. Thereafter, the tank was moved to one of the Moscow military testing grounds where it was demonstrated to K.E.Voroshilov. The tank's 122 mm gun was fired from 1500 metres at a captured German Panther tank.

      The round hit the side of the Panther's turret, penetrating it cleanly and tearing the opposite side out at the welded seams, throwing it back a few metres. During these tests the muzzle brake of the A-19 blew up almost killing Voroshilov. After this accident it was decided to change the muzzle brake to a 2-chamber design similar to that used by the Germans."

      I recall that these tests were actually performed at range, not with reduced charges. Also, as you can see, the tests were done after November 12th, 1943. IS-2 production was ready in December.

    14. @Steward Millen
      I responded to this bit on the AP shell of the 152mm :
      Battle of Kursk, the Soviets leveled their 122 mm and 152 mm guns at German heavy armor, because their 76.2 guns were found lacking, and found how "whoa!! these things do an awesome job
      Where you conflated the discovery of the anti-tank ability of the A-19 with the ML-20.

      Plus, the 122mm test hit the side turret of the Panther, not front hull.

    15. We were discussing the anti-tank performance of the A-19/D25 122 mm gun, and you bring up an article describing the testing of a HEAT round developed for the ML-30 122 mm howitzer (in the SU-122 as well as in artillery units) and the ML-20 152 mm howitzer (that went into the SU-152 ans well as artillery units). This is not relevant a discussion of the anti-tank performance of the A-19/D25 and moreover even with the ML-20 and ML-30 guns the HEAT ammo was in short supply and most of the time the HE round was used, which worked well enough. Nor is the fact that HEAT rounds were developed particularly telling, as most everyone developed HEAT rounds for their artillery pieces just in case they encountered enemy armor; it doesn't mean that they were being seriously considered in an anti-tank role. The SU-152 and the SU-122 were developed with infantry support in mind; it was from necessity at Kursk that they showed they could also take out enemy armor.

      As for a HEAT round for the D-25, the there was one developed that could be retroactively fit into it, in 1961. That's all I know about that.

      You were disputing my contention that it was battle of Kursk that alerted the Red Army to the potential of the A-19/D-25 as an antitank weapon, and my followup post I think I demonstrated that indeed, if was the combat performance of the A-19 against actual German heavy armor (Tigers and Panthers) that alerted Red Army designers to its potential in the IS tanks, and the actual testing was done later was to confirm and quantify the results already observed in combat. The A-19 was an effective wrecker of German tanks by battle, and this was demonstrated in actual combat at Kursk, not by testing or calculations--and you had questioned whether or not there was any evidence from actual battles that it was. I gave you examples both from Kursk and from an actual battle involving Panthers versus IS-2, at 1500 meters, with the Panthers even enjoying a 3:1 numerical advantage against the IS-2s yet the Panther unit got shot to pieces by the IS-2s, at a range that you seem to deny was even possible to get penetrations, at a minimal loss to the IS-2s. To me, you're arguing against an established fact.

      As for the 'the 122mm test hit the side' comment, if you look a the photo provided in this very post, there is a penetration shown; and the caption says of the Panther's front armor:

      The test results here show the side penetrations:

      But there are some questions here. One the penetration shown in this post appears different than the two penetrations shown in the second, and different Panthers appear to have been used. There is a tank '525' and a tank '445', and in the '525' (?..can't tell for sure) it's the rear turret plate, not the side armor plate, that has been torn off and is lying on the ground (plus the turret is turned differently). So the frontal 1400 meter penetration may be on tank '445' and the side penetrations may be on tank '525'.

      Peter, do know more about this in the documentation you have?

    16. Yes, a couple of Panthers were shot up. They are listed in this article, 525 is actually 535, but the bottom part of the number is destroyed.

    17. @ Stewart Millen,
      I'm sorry that you haven't read that I pointed out the Russians tested the 152mm AP-T shell in May 1943, before Kursk. (I am not including the 122mm HEAT shell in this discussion.) So saying that the Russians didn't know of its armor penetrating ability is a false statement.

      And if some Panthers were destroyed from 1.5 km from some hidden JS-2s it doesn't follow they were struck on their front hulls. As you probably know that when one side suffers high losses while the other very few it is often from ambush from the side or rear. So unless you have photos of the Panthers 'that approached Gerasimov' with 122mm holes in their front hulls my comments stand.

      Don't get your hopes up of being a 1400 meter penetration. That was thought to happen when struck at 718 m/s. Because of the firing table range error it works out to only about 600 meters.

    18. @Mobius,

      We were talking about the A-19's performance and you want to shift gears to the ML-20? As for the ML-20 on the SU-152, Wikipedia:

      "Although designed with no consideration for the anti-tank role , the SU-152 proved to have surprisingly good anti-tank capabilities due to the ML-20S's extremely heavy HE projectiles. Standard doctrine for purpose-built AT guns of the period universally relied on small, dense solid projectiles propelled to high velocities, optimized for punching through armor. Since the SU-152, like all SU-series self-propelled guns was not designed with tank killing in mind, no AP projectiles were issued to crews and no initial tests against armor were conducted"

      The use of the SU-152 and the 152 mm gun as anti-tank guns was an improvisation. Ditto with the A-19 at Kursk. I had recalled that the SU-152 crews weren't even issued AT rounds initially so they fought without them at Kursk; even after they became available, it was maybe just one AT round per vehicle because the large HE round was just about as effective.

      The IS-2, for its part, typically carried no more than 9 BR-471 or BR-471B rounds per tank, with the rest HE, because that was considered plenty.

    19. And if some Panthers were destroyed from 1.5 km from some hidden JS-2s it doesn't follow they were struck on their front hulls.

      There were 30 (!!) Panthers. There were only 10 IS-2 tanks. One of the flaws of the 122 mm D-25 that was reported by its crews was that it produced a lot of smoke when fired, giving away its position--so those IS-2s wouldn't stay hidden very long.

      And you keep telling us that the D-25 not only lacks sufficient punch, it lacks accuracy too! So according to you, a lot of that first salvo from the IS-2s fired from 1500 m would have missed the Panthers, giving them ample time to turn their hulls to face the IS-2s.

      Now, with a 3:1 advantage in numbers, and each Panther being able to push out 6-8 rounds per tank per minute, while the IS-2s (and these are undoubtedly early-model IS-2s, with the inferior "gumdrop" sight and the slowerer reloading time) can maybe crank out 2 rounds a minute. So even if only 20 Panthers returned fire, that's 120 rounds of Kwk42 ammunition you describe as highly accurate and potent flying towards the IS-2s while only maybe 20 rounds of D-25 rounds during the same time frame, rounds that you describe as being both inaccurate and lacking sufficient punch, are returned.

      (Now, I am not saying that in actual tank fights crews push out the maximum # of rounds, any more than they push the tank to its maximum speed always, just that the ratio of exchange over an equivalent time would be about 6:1 in favor of the Panthers, assuming that both sides have equivalent delays. But then again, if you're in a Panther and you've already acquired an IS-2 and are hitting it, why *not* pump into it shots as fast as you can?? Why would you want to re-aim?).

      Yet, when the smoke literally clears, the German Panther unit has lost 2/3rds of its tanks, 20 tanks in all with 15 irrecoverable losses, while only 2 IS-2s were lost (1 irrecoverable). Usually, the simplest answer is the best, and the simplest explanation of what happened during that engagement is that, at the range of 1500 meters, that:

      a) It's probably true that given the Panther's great advantage in rate of fire, the fact that the Panthers had great numerical superiority, and the fact it had an accurate gun, probably a fair number of Kwk rounds did in fact hit those the IS-2s. But the vast majority of those rounds, at 1500 meters, was just 'plinking' the IS-2s to no effect. Eventually with enough hits you either hit a weak spot (say, the IS-2's lower hull, or a spot thereof not covered by spare tracks) or you luck out and hit the 100 mm frontal cheek armor or 110 mm mantlet at a low-probability, near-normal angle of incidence.

      b) When the D-25 round hits a Panther, no matter where the round lands, it equals 'game over'. The Panther is either put out of commission if not totally. As one Soviet tanker said "with the IS-2's 122, one hit was usually all that was required". That's why the Soviets kept it on the all their postwar heavy tanks until they put an improved version on the T-10. Why would you think the Soviets would have stayed with the D25 unless they too thought it was a perfectly good gun.

    20. So unless you have photos of the Panthers 'that approached Gerasimov' with 122mm holes in their front hulls my comments stand.

      Then you'd just claim that the penetrating round wasn't fired from 1500 meters, in the absence of any certification of range. You know as I do that most actions aren't accompanied by photographers and even if there were any present, the photographs may not have survived or have been published.

      But I can give you this, one of Peter's post. A test done at close range, but against a target far tougher than a Panther-- the IS-3, and comparing the D-25 versus not the Panther's Kwk42, but against the even better Kwk43.

      So if the D-25 can beat the Kwk43 in at least some actual tests at specified, known, ranges, why do you have this problem saying it was also maybe a better gun a weaker gun when fired at weaker armor?

    21. @Stewart Millen
      You continuously provide data of shots at incorrect ranges to prove that the ranges are correct. Do you not see the fallacy in that?

    22. Here's the deal:
      The 122mm can take out a Panther for sure at 1.5km.
      The turret, lower plate and sides are extremely vulnerable against an 122mm AP shell even at long range.
      And I don't doubt that at one point the shell was able to penetrate a Panthers front armot at 1.5km due to decline in German armor quality.
      However against good quality Panther armor I doubt this would be the case.
      Lets look at another shell as example:
      The 120mm T116 APBC shell weighs roughly 22.13kg without windshield and penetrates 101.2mm of armor at 55° with ~766m/s under army criteria, meaning that it counts as complete penetration as long as light shines through a crack made.
      Against an 80mm plate the velociy required would be around 681m/s from the differences in thickness and energy required. Overmatching of the plate might lower the velocity but since it's army criteria lets assume 681m/s is enough to completely penetrate the armor.
      The 122mm AP weighs 25kg so it puts around 9.2% more mass against the same area, lowering the velocity to 651m/s.
      From the ballistics of the shell this would mean that it can penetrate 80mm at 55° at around 1140m. Which also matches with my calculator if I give the Soviet shell the same quality as the US shell which should be alright since shell quality is generally more important against flat armor when the shell pierces the plate.

      So even under favourable conditions I don't see the 122mm AP shell penetrating the Panthers armor at more than 1.2km, unless the armor was, due to brittleness, more susceptible.
      Something that would also allow the 122mm to outperform the 100mm when it comes to penetrating the Panther at longer range.

    23. @Mobius

      So you are now disputing the ranges of the IS-3 testing I linked too as well?

      Not only that, even if you allowed for the ranges being incorrect (which I continue dispute) the 122 mm is still outperforming what you contend it could do by those tests. That by itself not give you pause?

      The reality is what happens on the battlefield, not figures on your sheet of paper. As I said, there are reports from battles like I cited, plus providing fire support from a 1.5-2 km range was the recommended procedure for both IS-2 tanks and ISUs. The Soviets would not be recommending this if the 122 mm gun a) lacked sufficient accuracy to hit anything at that range, or b) lacked sufficient punch for the job.

      The ISU-122 in particular was used in the 'ambushing the ambusher' role--by sitting back at long range overseeing a Soviet advance, and taking out any German heavies popping out from cover to ambush the advancing first-line Soviet tanks and infantry. This tactic would not have worked if either the 122 mm missed most of the time at that range, or the round usually simply shattered or bounced its target at that range. In such cases, the German "ambusher" would have soon ducked back into cover; for this tactic to work the round has to have a high chance of both hitting and also disabling or destroying its target.

      One of the jobs of any historian is to reconcile apparently contradictory evidence. You are discrediting every piece of evidence contrary to yours save what's written on sheets of paper. I am not disputing your evidence per se, no more than I dispute, say, Soviet IS-2 reports of their rounds also bouncing at relatively short ranges (600-700 m) off the Panther's upper hull--as I said, the WW2 weapons site also shows that the uncapped BR-471 round has a significant shattering chance there, which led to the BR-471B round development, and there obviously QC problems with all German armor. I think a combination of these explains that.

      As for the October 1944 WaPruf values, these are calculated values, not actual test results. I have replicated some of those calculations myself, and they show no penetration by the 122 mm against the Panther's upper hull at 30 degrees simply because they don't take overmatching into consideration--just like they also mistakenly have a T-34/85's hull bouncing a Kwk42 round past 300 meters and suggest that the turret of the T-34/85 is by far weaker than its hull (when a survey of knocked out T-34s (posted here by Peter) showed quite the opposite--more kills by hits on the hull than turret).

      In short, I try to explain and reconcile any contrary evidence, not just deny it. As for your ballistics data, the IS-3 test results comparing the 122 mm and the Kwk43 that Peter posted and I referenced should cause you to take pause. I say that because even using the Bird and Livingston data which you so disagree with, the 122 mm **should not be penetrating the armor in some of these tests at ANY range**, PERIOD, let alone with the reduced ballistics. But the holes are three. Here we're talking about good-quality Soviet armor, not dubious-quality German armor.

      Maybe that should raise the possibility that just perhaps there's something about the 122 mm gun and round that is not modeled well by the Demarre or other calculations? That, for some reason, it overperforms the calculated values? These equations can produce known deviations from observed data.

    24. So you are now disputing the ranges of the IS-3 testing I linked too as well?
      Of course. Until they corrected the firing table data all stated range to when something penetrates is subject to doubt.
      I don't know what formula the Germans used but if you use the Soviet's own DeMarre formula with K=2400 the 122mm does not penetrate at any range.

      Killakiwi, had the best approximation but that is with the D-25/A-19 gun with a MV=795/800 m/s. The D-25T of the JS-2 had a MV=781 m/s so the range would be a little less.

      As for the SU-152 I don't know if they had APHE by the time of Kursk or only had HE and anti-concrete shells. At Ponyri there was a case of a Ferdinand penetrated in the side from 800 meters by a SU-152.

    25. Mobius,

      The IS-3 tests show penetrations using the 122 mm gun, both BR-471 and BR-471B rounds, when there *should be no penetrations at all* even at *point-blank range*, by the Bird/Livingston data and even more so with your data. Even when you throw in overmatching, it doesn't explain the results.

      That makes all your ballistics data irrelevant; it doesn't matter what velocity the gun/round has if--whatever it is--it penetrates. You can quibble that saying that the round really has 781 m/s instead of 800 m/s, but it's really irrelevant. You can argue that a penetration at 900 meters really only means it should only happen at 500 meters or less, but that's still inconsequential to this discussion. The Bird and Livingston values say *no penetration, even at point-blank range" and you want to make that disconnect with reality even greater, instead instead of correcting it to reality.

      And no, here it can't be bad armor because the same armor that is yielding to the 122 mm is also bouncing both the standard Kwk43 APCBC rounds and Kwk42 APCR rounds.

      Before I rant on: Peter--I think I've asked this question before-it's not clear to me that in these tests whether or not the 80 % or the 20 % penetration criteria is being used. There are terms like "can be penetrated", "is reliably penetrated", "crew is completely protected", etc. in the descriptions and I'm trying to read between the lines. My own inclination is that Soviet testing is conservative; when they are testing their own weaponry against possible use by enemy weapons; they use the 80 % penetration criteria; but they often use the 20 % criteria when evaluating their own armor's vulnerability to enemy weaponry.

      Like the IS-2 Model 1944 should be impenetrable to the Kwk43 even at point-blank range using Western criteria for penetration and slope modifiers, even for a cast hull (and both welded plate and cast hulls were used, I recall) but your article says the limit is 600 m:

      "Frontal plates *fully protect* the crew against fire from 88mm German armor-piercing shells from 100 meters under any angle, while the upper frontal plate of IS-2 protects only on distances of 600m and higher"

      That 'fully protects' makes me wonder if the 20 % criteria is the one being used.

    26. I've always taken "can be penetrated" as the PTP criterion (rear of the armour is compromised in some way) and "reliably penetrated" as PSP (complete penetration, round passes through the plate). Meanwhile, the Western (at least British) standard of penetration is that light can pass through the plate, so somewhere between PTP and PSP.

      PTP is often matched to 20% penetration chance and PSP to 80% penetration chance.

    27. Thanks Peter, for the clarification.

      Looking at the holes in the front of that IS-3 pike nose (upper glacis plate) by 122 mm rounds, it seems to fit at least the British definition of penetration--these seem to be complete holes through the armor, though they of course don't indicate how much of the round went through. If that's so, these tests do conflict with the Bird-Livingston data, which have the upper limit at 197 mm for BR-471 and 205 mm for the BR-471B against vertical, homogeneous, plate.

      Assuming that the 320 and 40 degree tests were done to eliminate the horizontal slope component from the plate (about 18 degrees), after doing that the effective armor penetrated is 110 mm @ 55 degrees (US army equivalent slope multiplier of 2.1) so it's 231 mm; overmatching knocks this down to 210 mm for the BR-471 round. So this is 210 mm horizontal plate penetrated nominally at 900 meters--Mobius can argue that this stated range really represents a range of less than 900 meters, but even if it was done point-blank it's a deviation.

      The frontal 0 degree test including the horizontal and vertical components of slope (again, using US Army factors) predict like a 240 mm equivalent of vertical plate; overmatching by the 122 mm BR-471B round knocks this down to 218 mm but you get at penetration by at least British/US criteria at 200 meters. Same caveats about range apply.

      Meanwhile, the Kwk43 shells (235 mm penetration at point-blank range by the Bird/Livingston translations from German tests) should go through the front upper plates at 40 and 320 degrees (or come close to doing so) but seem to be completely rebuffed.

      I've always thought the Bird/Livingston values for German guns was at least 5 % high; this is in part I remember seeing the values for these guns back in the 1970s, in S&T magazine and elsewhere, that were lower by about--5 %! That obviously didn't come from the Soviet data you posted, nor could it be German, so it likely was from US/British testing done on captured weapons. This is consistent with the British/US tests being done with captured German ammo as-issued as opposed to cherry-picking rounds like the Germans did.

      But these test also suggest the penetration data for Soviet guns by Bird and Livingston is low, or at least the 122 mm.

    28. @Steward Millen
      I had to look up elsewhere what armor thickness you are assuming. All I have in that article to go on are penetration distances.
      I guess object 701 had 140mm @ 60° and JSIII had 100mm @ 60° though they are prototypes so who knows?

      The upper front plate of the IS-3 hull can be penetrated by 122 mm sharp-tipped shells from 900 meters.
      A remarkable feat as the corrected tables of the DDR only gives their own D-25T a 123mm @ 90° penetration at that range.

      Data on the resistance of hulls to shells is provided in tables ## 8, 9, and 10." ??? Apparently missing...

      The factory #200 hull exhibits similar properties. No guns can penetrate the upper front plate, at any distance or tested angle.
      So the 88mm cannot penetrate 140mm @ 60°. Good catch. Go tell Captain Obvious. The Yugo tests came out at least 10 years ago and they showed it couldn't penetrate 101mm @ 60° of 290 BHN armor.

      The IS-3 tests show penetrations using the 122 mm gun, both BR-471 and BR-471B rounds, when there *should be no penetrations at all* even at *point-blank range*
      This is not my penetration formula but is the Russian ARTKOM DeMarre formula. Look at all the ARTKOM tables and it shows they were calculated with K=2400 factor. But it probably doesn't work for angles over 30 degrees.

    29. Here's the deal 2:
      Penetration doesn't mean everything.
      A 88mm APCBC shell penetrates a lot of vertical armor because it "pierces" the plate. At least if we are talking about ductile armor. Piercing is very efficent in defeating armor, hence why APCBC shells, that have a cap to prevent the nose from deforming, can defeat plates at low obliquity very well even at high velocity. Plain AP shells generally can not pierce thick plates because at high velocity the sharp nose of AP shells will deform or break, lowering the effectivness of the shell to defeat the armor. Very hard armor offers great resistance against piercing. However since hard armor is generally more brittle it will break appart instead of deforming like ductile armor.

      Highly sloped armor is also unaffected by the piercing ability of AP shells, hence why APC shells have no advantage against such armor. The armor is simply defeated by the kinetic energy of the shell deforming or breaking the plate.

      An 122mm AP shell fired at 795m/s should have no or only a slighty advantage against 88mm APCBC shell fired at 1000m/s against sloped armor at 60°. Yet the 122mm defeated the frontal armor of the IS-3 while the 88mm couldn't. How is that possible?
      The only explantion is that the armor in the test was of very high hardness which made the armor easier to defeat by a large heavy shell that shattered the armor using its momentum.
      If we compare the numbers we see that both rounds defeated the plate at a velocity where both rounds roughly had the same momentum per area. Since the 122mm is much heavier it required less velocity to break up the armor and push it out of the way.
      If the armor was of low to medium hardness, and therefore more ductile, neither shell would not be able to defeat the armor.
      When the 122mm was tested against the cast front armor of the M48 medium tank, the shell could not defeat the 110mm sloped at 60° even from close range.
      So the 122mm shell only has an advantage over the 88mm when fired against brittle armor that is easier defeated by momentum instead of the KE energy required to pierce and deform the plate.

    30. Mobius

      A remarkable feat as the corrected tables of the DDR only gives their own D-25T a 123mm @ 90° penetration at that range.

      Using what penetration criteria? The data in this table looks similar to the Soviet 80 % penetration data, just a little lower, which would be expected if you lowered the muzzle velocity from 800 to 780 m/s.

      And, judging from what I can read from the top, it's the BR-471 round.

      So the 88mm cannot penetrate 140mm @ 60°. Good catch. Go tell Captain Obvious.

      You've misunderstood the data. Two tests were done against the IS-3 upper hull plates; the 900 m penetrations were achieved at 40 and 320 degrees, to the right and left, respectively, in an apparent attempt to remove the horizontal slope component of approximately 18 degrees of the "pike" nose. The 200 m penetration was *also* against the IS-3 upper hull plates, but done head-on, at zero degrees, to include both vertical and horizontal slope components. Both penetrations seem to fit at least the British/US definition, so the penetration definition there matches Livingston/Bird (which was I asked Peter).

      The Kwk43 failed to penetrate the same upper plates in both tests, even though in theory from Livingston/Bird it might have succeeded in the tests done at 40 and 320 degree horizontal angles. So the Soviet gun overachieved the Bird/Livingston data while the Kwk43 underachieved.

      The 701 hull tests (140 mm @ 60 degrees) had both guns failing to penetrate, as would be expected. You confused this test with the others.

      This is not my penetration formula but is the Russian ARTKOM DeMarre formula. Look at all the ARTKOM tables and it shows they were calculated with K=2400 factor. But it probably doesn't work for angles over 30 degrees.

      *Forget formulas*. Look at those holes in the armor, according to you there should be no holes. Also note the scuff marks made by the Kwk43 where their *might* be a hole in the angled tests.

      The purpose of engineering formulas is to model and predict real-life experiences, not vice versa. Both the Bird/Livingston data and your reductions of it fail to predict this event. Nor would the testers of the IS-3 hull tests be motivated to press their thumbs on the scale in any way to rig these tests; they were trying to develop an impenetrable IS-3 or IS-4 hull, not to prove that the 122 mm was the world's best anti-tank gun. So these tests say, to some extent, they failed.

      This weekend I played around modeling this. If you assume these tests provide a better view of reality, and I can't see why they don't, then if you use the reduced velocities you advocate but also use these tests as a basis for an indication of the penetration of the D25-T at a range of zero meters @ 780 m/s, you get a model that seems to predict the observed reality pretty well. Now penetrations of the BR-471 round on the Panther's hull extend out further, not just a bit past c. 1500 meters according to Bird/Livingston but past 2000 meters, as the Soviets observed, but there is a range between 600-1100 meters where round shattering is predicted to be likely. And it was failure to penetrate at these ranges, of course, was a reason why the BR-471B was developed.

      I then also tried it on the Tiger II. The model seemed to match Soviet testing pretty well on the turret (500 meters max with the BR471, a bit further on the BR-471B). It wouldn't predict the failures of the Tiger II hull observed but the Soviets noted those appeared at the weld seams, which would be hard to model and not representative of the whole hull.

      Consider it a 'hypothesis'.

    31. @ KillaKiw

      Quick drive-by comments.

      1) The Panther's turret (at least the mantlet; which composes the fast bulk of it) is not weaker than the hull, it's actually stronger (caveats thrown in). That's because the median angle of impact of any incoming round will be about 50 degrees to the vertical; though the Germans appear in their WaPruf1 October 1944 calculations appear to have used 45 degrees as the median angle. (They also seemed to have used 35 degrees as the median impact angle for the IS-2 model 1943 and T-34/85 rounded surfaces, which is close to what I assumed too). Yes, about 10 % of incoming rounds will be less than 15 degrees, and have minimal slope enhancements, but on the other hand about 20 % will hit at an angle of > 65 degrees. That, and the fact that the mantlet is thicker and less overmatched by the 122 mm then the hull, means that a penetration is less likely there than on the hull.

      There are small 100 mm thick areas around the mantlet, minimally sloped, which are vulnerable to lots of things, but then again there's this 300 mm ring around the gun which is invulnerable to almost anything WWII.

      2) Soviet armor was harder, but less brittle, than the softer German plate, because they used superior alloys. There were some problems on early IS-1s and IS-2s with non-penetrating spalling, but on the whole Soviet armor had a minimal risk of cracking/spalling/breaking compared to German plate. I have seen lots of pictures of knocked-out IS-2s, and a couple really shot up, but the only cracks or irregular holes I have seen in them are where edge effects may have played a role (like near a gun port). Peter has published on this site a Soviet analysis on the spalling associated with hits of their own knocked-out tanks, and only about 2 % were affected (by memory).

      German plate, despite being less hard, when bad tended to crack or even shatter like glass.

      I think the failure of the Kwk43 to penetrate was simply it didn't have enough penetration. As I said, I recall figures published back in the 1970s having a penetration of 207 mm at 500 meters, not 219 mm, as the Bird/Livingston translations of German testing has. As the Germans cherry-picked their rounds for their tests, if one assumes a +/- 10 % variance of the results, what you do is that you throw out all the lower-than-average scores and the "low" figures are what would have been your "average" if you had not done that. I think the point-blank penetration of the Kwk43 is more like 220 mm instead of 235 mm.

    32. I found the source of the 1944 incorrect firing tables.
      Page 6 of this report.!XO5mAILR!kwFgFDmDdsHEdFb3tk0oI7t8Kfx9PkP8Zeo-qfldKTw

      In tests High hardness armor had an advantage over RHA in T/D ratio of 1.10 or more. It was distinctly inferior when T/D was 1 or less.

    33. Unfortunately, Mobius, I don't read Russian, and can't copy-and-paste into Google for a crude translation, and I looked for this claim about T/D. Not doubting you, just didn't/couldn't.

      However, this report does describe the testing on the King Tiger, with detailed hit-by-hit description by each round. Here again, you see penetrations of the 122 mm where the Bird/Livingston penetrations predict none possible, even though the thickness of both the King Tiger turret (185 mm) and upper hull (150 mm) are considerably greater than the size of the penetrating rounds (122 mm, 100, and Kwk43 88mm), while the Soviet 152 mm round barely just matches the Tiger's hull thickness. So overmatching of the King Tiger's high-hardness rolled armor cannot be the cause of failure in this instance.

      I know outliers exist, and in empirical formulas like Kruppa and DeMarre you'll always have them. Again, to me it seems to explain things better if you used the 1957 ballistic table you propose and a point-blank value of c. 225 mm or mroe for the BR-471, and 4 % higher than that for the BR-471B. I'd also think the Kwk43 point-blank value should be about ~ 222 mm or so and all other German values should be at least 5 % lower. I have plugged these values into the WW2 gun and armor calculator and everything seems to make sense (save penetration #4 on the Tiger II hull, by the 122 mm, which I'd just accept as an outlier).

      I also note when you take the 1957 ballistic data you propose, and match it in the DeMarre equations against the German 128/L55, which is the closest equivalent and its velocities and rounds, then you get c. 220-230 nm predicted penetration. So it's not like there is no theoretical justification either.

    34. @ Stewart Millen
      I didn't bring up Bird & Livingston values as I don't use them.
      What my original comments were that the ranges stated for the 122mm and 100mm penetration of the Panther were wrong. As you can see when you compare the given velocity m/s of numbered hits in the 1944 King Tiger test to their assumed ranges. (You don't need to read Russian. Just read the numbers.) Then compare that velocity to the 1957 firing table. For example: hit #33 122mm pointed AP 662.6 m/s is 2400 m range. But in a 662.6 m/s impact the range would actually be 1062 m by the firing table in the 1957 document.

      BTW, the Tiger II didn't have high hardness armor. It was rather soft. Russians used high hardness armor.

  6. The 122 is not 'overestimated' by firing tables, it actually outperforms the expected penetration against the Panther and most targets. In part this is explained by overmatching but even overmatching only predicts penetration of the Panther's mantlet and upper hull at c. 1500 m while the Soviets observed penetrations at 2000 meters and above. Because of overmatching, the 122 mm against most targets outperformed at the 100 mm, which is one of the reasons why the Soviets kept it on the IS-series tanks.

    Actually, I think the Panther (against an IS tank at least) is way better off at very close ranges, because of its faster rate of fire.

    1. In my opinion bigger rate of fire that's important advantage, but from other hand, in my opinion, during gunfight "IS-2 vs Panther", IS-2 have better chances to penetrate Panther, than Panther to penetrate IS-2. I think about side armour. Typical tank have 2 times bigger lenght than width. Due this feature, in case when glacis is horizontally angled at 30 degrees, around 50 percent of hull silhuette that's side armour (from enemy gunner position). And side armour in this case is angled at 60 degrees. Lower side of Panther hull that's 40 mm. Also if we include 5 mm skirt, we have only 90 mm LOS. Not bad, but in this same case IS-2 have 180 mm LOS (90 mm side armour of IS-2 hull).

    2. My reason for arguing for close ranges (for the Panther, and also the Tiger II, though 'close' for the latter is 'c. 1000 m' while for the Panther it's like "< 500 m") is that:

      1) There are more vulnerable frontal areas to the Kwk42 and Kwk43 at those ranges, plus the side is more vulnerable too;

      2) The vulnerable areas are much more targetable where at long ranges you 'just hit the tank' and if you happen to hit a weak spot (usually small) it's just dumb luck.

      3) Especially (and this is tactics) if the German tank gets the element of surprise, the faster rate of fire of its gun can allow it to pump round after round after round into the presumably stunned/surprised/panicked/etc Soviet tank with each hit at that range has a good chance of a kill.

      At long ranges, the German tank is more likely to be 'plinking' its Soviet rival, as aiming for vulnerable points per se isn't possible, and most shots will be bounced or absorbed. The IS-2 on the other hand, usually just needs to get one hit in (even with HE on the King Tiger) and the German tank is hurting if not disabled.

      That's my reasoning. I agree with you on all your observations, though.

  7. So, a 1.5% difference in velocity in tests compared to firing tables (which are made with smoothed data, corrected to the same atmospheric conditions, mad from multiple shots from different lots of ammunition) is somehow significant? You'll find more variation in ammunition from the same lot, fired on the same day, from the same gun.
    Be careful when diving down the rivet counting Rabbit Hole. Not only is context everything, but numbers presented in isolation are not something to pin a conclusion on.

  8. I wonder about the ergonomics versus armor thickness issue. Chieftain often complains that tanks, like the T34, are cramped, and therefor hard to operate efficiently. As a tanker, I'd take a cramped compartment over a "roomy" one any time, since it means more armor thickness as a tradeoff. Also, short tankers in general used to be chosen over their taller comrades, similarly in the Submarine corps. The Panther is a great balance of attributes, but its height, in my humble opinion, is one of its definite weak points. The greater the cross section, the greater change of being hit, especially when trying to fight from defilade. Same with the M4 Medium (Sherman). The British and Russians, in particular, seemed to understand that smaller is better. I guess the Germans were just a larger "Arian stock."