Pak 38 Pzgr.40 and 40/1

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Yoozername
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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 30 Nov 2018 18:41

Some thoughts...
The 50 mm Pzgr.40 weighed .92 Kg, the 40/1 1.07 Kg (cores in their 50 mm rounds)
Those weights are actually for the whole projectile weight, not the core weight. The core weights are equal. About 3/4 of a pound according to TM-1985-3.

The propellant weights must be different, given the difference in KE between the projectiles. But that is another subject. The KE can then be misleading....

KE = 1/2MV^2
KE (40)= 640.5
KE (40/1)=683.1

In terms of penetration, they both actually have the 'same' actual penetrator. That is, the 'bolt', and while there will be a difference in flight characteristics, the end effects will be dependant on velocity at that range. Penetration for the '40' probably would be greater at shorter range, the '40/1' would probably overtake it at longer ranges.

Given the shorter ranges this ammunition should have been used at, they were both probably extremely accurate to the point of being immune to range estimation errors. Even accurate enough to be more selective regarding the actual area of the target to strike. If you look at the mechanical drawings I posted above, the 40/1 has a streamlined body while the 40 has a 'notched' body.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 30 Nov 2018 19:16

Report of the 2./Panzerjäger-Abteilung 128 in reference to the effects of the projectiles fired by the anti-tank gun of 5 cm Pak 38 on Soviet tanks during the operations of the so-called 'second battle of Kharkiv'.

Note :
In the section of 'Beutepanzer' can be read another report of the 2./Panzerjäger-Abteilung 128 dated in June of 1944 in reference to the experiences lived with T-34 and SU-85 captured and in service within this unit.


2./Panz.Jäger.Abt.128

With reference to : Report on experiences

Directed to the Panzerjäger-Abteilung 128



Report on the penetration effects of Pak 38
during operations in Bereka and Dudkowka between 12 and 20.5.1942



During the battles in Berewka, partly against superheavy tanks, the 2./Panz.Jäger.Abt.128 practically lost its complete material, 8 cannons and 7 harmonics (transports?). The Company is of the opinion that the reason has been the insufficient effects of the 5 cm Pak 38 .

During the 13th and 15th of May, 1942, and in the course of repeated attacks by heavy and super-heavy tanks, more than 1500 projectiles were fired: 1280 projectiles Pz.Gr.38 and approximately 220 projectiles Pz.Gr.40. Of these projectiles a minimum of 1000 reached their objectives. The final result of these two days have been 14 tanks destroyed: 1 KW II, 5 T-34, 8 unidentified media models; 2 KW II were damaged.

The destroyed KW II was shot down under extraordinarily favorable circumstances as it was caught in its weakly armored lower chassis plate when the vehicle was passing through a small pothole. On the rest of the superheavy tanks no type of effect of the shots has been observed. In relation to the ammunition used, the final conclusion can be reached that 107 shots of Pak 38 have been required per tank destroyed.. In spite of the fact that this figure offers a distorted image, because in addition to the 14 destroyed tanks, many other tanks were also shot that were not damaged, it is a fact that a medium or heavy tank can only be destroyed by a very high consumption of ammunition.


The combats in Dudkowka offer a more positive image because here the Company faced lighter tanks (T-26, Mark II and T-34). The final result in relation to the ammunition consumed is here between 15 and 20 projectiles per tank destroyed.


This means that against the medium and heavy tanks that the enemy currently employs the penetration power of 5 cm Pak 38it is totally insufficient, since in most cases it is not possible to carry out such a high number of shots before the tank has reached the firing position.


Effects of the Panzer-Garnet 40 :
The effects of the Pz.Gr.40 at short distances on medium and heavy tanks have been satisfactory; On superheavy tanks, no type of effect could be observed. The Pz.Gr.40 has caused in many occasions faults in the loading system that could not be repaired by the servers of the cannon. These problems have led 3 times to the total loss of the cannon.

Effects of Panzergranate 38 :
Its use has not caused problems in the canyon, but its drilling effects on heavy and medium tanks do not satisfy. It has not been possible to perforate the frontal armor in any case.

Effects of Sprenggranate :
Satisfactory effects on non-armored targets.


Conclusion :
For the effective combat of armored attacks it is necessary either a 5 cm ammunition with a much greater penetration power, or the equipación of the companies cazacarro with a heavy platoon armed with cannons of a greater caliber.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 30 Nov 2018 19:47

Yoozername wrote:
30 Nov 2018 18:41
In terms of penetration, they both actually have the 'same' actual penetrator. That is, the 'bolt', and while there will be a difference in flight characteristics, the end effects will be dependant on velocity at that range. Penetration for the '40' probably would be greater at shorter range, the '40/1' would probably overtake it at longer ranges.
In a normal AP shell energy is taken by the destruction of the windscreen and AP cap. While there is no AP cap some energy has to be lost in destruction of the windscreen cap by the bolt. The destruction of the light case or 'husk' of the projectile probably doesn't effect the bolt penetration at all.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 30 Nov 2018 20:09

It appears that there is a thin screen and it is filled with a bakelite type material...hopefully it doesn't shatter the tungsten carbide bolt when the bakelite gets turned into powder....note: this appears to be a '40' projectile of the later type...click on the picture then click + to magnify...note the ammo collector did not cut into the actual bolt...He would have wrecked his tooling....

One person asked if any of the collectors, who have been doing this stuff for a long time, and some are EOD guys, if they ever came across an actual 40/1....apparently not. It may have been designed but not implemented especially after 1943. I suppose it may have been possible to refurb the projectiles from the short 5,0 cm KWK for the Pak 38 and KWK 39.
50mmbaked.jpg
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Re: Pak 38 Pzgr.40 and 40/1

Post by Miles Krogfus » 01 Dec 2018 22:23

There was no ballistic tabulation with times to ranges, velocities, accuracy and other data in any 50 mm guns FT booklet on Pzgr.40 to be used by gunners like the one I posted above for Pzgr.40/1. Likewise there was only the 50 mm Pzgr.39 APBC tablulation, none for the non-capped AP.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 02 Dec 2018 21:58

Let's see if we can find one more data point from this. If we just go by the penetration of the bolt then we see that the APCR penetrates 72mm at 500m. Now we have the APCR/1 penetrating 76mm at 500m and penetrating 68mm at 600 m. So it would penetrate around 72mm right between these two. In that case we could average the strike velocities of 862 m/s and 811 m/s. That would give 836.5 m/s. So at 500m the APCR would be about 836.5 m/s.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Peasant » 03 Dec 2018 03:48

Ever heard of the "Middle Ground" fallacy? TL;DR: sometimes there is only right and wrong answer, and averaging these two doesnt bring you closer to the right answer.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 03 Dec 2018 04:19

Peasant wrote:
03 Dec 2018 03:48
Ever heard of the "Middle Ground" fallacy? TL;DR: sometimes there is only right and wrong answer, and averaging these two doesnt bring you closer to the right answer.
I perfer Newton's method.
Though something might be learned from the British Ordnance Board's December 15,1943 Curve OB/43/CV 23, Miles mentioned.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 03 Dec 2018 05:31

Peasant wrote:
03 Dec 2018 03:48
Ever heard of the "Middle Ground" fallacy? TL;DR: sometimes there is only right and wrong answer, and averaging these two doesnt bring you closer to the right answer.
Yes, I have. And I understand it as it is intended. Please explain how you 'understand' it?

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Re: Pak 38 Pzgr.40 and 40/1

Post by Peasant » 03 Dec 2018 05:46

Yoozername wrote:
03 Dec 2018 05:31
Peasant wrote:
03 Dec 2018 03:48
Ever heard of the "Middle Ground" fallacy? TL;DR: sometimes there is only right and wrong answer, and averaging these two doesnt bring you closer to the right answer.
Yes, I have. And I understand it as it is intended. Please explain how you 'understand' it?
Great, now I've pissed someone off for correcting one of the forum's veterans...

Here you go: https://en.wikipedia.org/wiki/Argument_to_moderation

So, why am I wrong ?

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 03 Dec 2018 07:55

I am amused, not pissed off. And you haven't corrected anyone.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 03 Dec 2018 15:29

Using the idea that the APCR had a strike velocity of 837 m/s at 500m I created a curve and table. One thing is that didn't line up is the 1135 m/s at 100m. If that was from the British curve I found data that the US/UK assumed a MV of 1198 m/s.
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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 03 Dec 2018 18:21

There is a major technical difference between the projectile types. Namely, where the driving band is. On the '40' version,m the driving bands are on the front part of the projectile, while the '40/1', they are on the back like most projectiles. Hence, the '40' sits deep inside the cartridge case and takes up room.

My feeling is that the '40' is much less accurate than the later version, but it probably had acceptable accuracy out to 500-600 meters or so. There are anecdotal and even report discussion of these type of projectiles causing stuck brass and ejection problems.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Miles Krogfus » 03 Dec 2018 22:46

Some British material on Pzgr 40:
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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 04 Dec 2018 02:26

Great stuff! I wonder if this data actually came from a German document. These projectiles have the velocity to cross over the various plate hardness 'zones' and have a non-linear response.

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