Pak 38 Pzgr.40 and 40/1

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Miles Krogfus
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Pak 38 Pzgr.40 and 40/1

Post by Miles Krogfus » 10 Jun 2015 18:40

Krupp made 1,911,102 21 mm diameter and 75 mm long tungsten cores for 50 mm Pzgr.40 and 40/1, ceasing all tungsten core production July 1943. In 1943 each core cost 8.33 Reichmarks, (compared to 20.85 RM for each 75 mm gun tungsten core, 37.57 RM for 30 mm diameter and 60 RM for each 36 mm diameter core for 88 mm guns).
The 50 mm Pzgr.40 weighed .92 Kg, the 40/1 1.07 Kg (cores in their 50 mm rounds). Cores of 89% Wolfram, 5.55% Carbon, 2.5% Nickel, Rockwell Hardness 75, muzzle velocities of 1180/1130 m/s given in FT H.DV. 119/312.
A Krupp 30 degree deflection penetration curve chart for all caliber tungsten cores show these figures for Pzgr.40/1 with these FT velocities: 100 meters 1074 m/s 113 mm perforated, 200m 1019 m/s 103 mm, 300 m 966 m/s 92 mm, 400 m 913 m/s 81mm, 500 m 862 m/s 76 mm, 600 m 811 m/s 68 mm, 700 m 763 m/s 61 mm, 800 m 717 m/s 52 mm.
800 meters was the greatest distance Pzgr. 40/1 should be fired, 600 meters Pzgr.40.
(At 100 meters 1135 m/s, Pzgr.40 officially perforated 130 mm with 30 degree deflection.)
The British Ordnance Board's December 15,1943 Curve OB/43/CV 23 shows Pzgr.40. With a velocity of 1135 m/s against UK plate it had 152 mm CV penetration at 0 degrees, 123 mm at 30 degrees deflection.

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

Post by Yoozername » 11 Jun 2015 05:55

Is the 1,911,102 number just the 5,0 cm? Or all the calibers?

I believe the 7,5 cm PAK 40, KWK40 and ex-soviet 7,62 PzGr 40, and also the 75/55 squeezegun 7.5 PzGr 41{HK} all used the same core? Or core size? 111mmx28mm.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 11 Jun 2015 07:28

Miles Krogfus wrote: Krupp made 1,911,102 21 mm diameter and 75 mm long tungsten cores for 50 mm Pzgr.40 and 40/1, ceasing all tungsten core production July 1943. In 1943 each core cost 8.33 Reichmarks, (compared to 20.85 RM for each 75 mm gun tungsten core, 37.57 RM for 30 mm diameter and 60 RM for each 36 mm diameter core for 88 mm guns).

The 50 mm Pzgr.40 weighed .92 Kg, the 40/1 1.07 Kg (cores in their 50 mm rounds). Cores of 89% Wolfram, 5.55% Carbon, 2.5% Nickel, Rockwell Hardness 75, muzzle velocities of 1180/1130 m/s given in FT H.DV. 119/312.

A Krupp 30 degree deflection penetration curve chart for all caliber tungsten cores show these figures for Pzgr.40/1 with these FT velocities:

100 meters 1074 m/s 113 mm perforated,
200m 1019 m/s 103 mm,
300 m 966 m/s 92 mm,
400 m 913 m/s 81mm,
500 m 862 m/s 76 mm,
600 m 811 m/s 68 mm,
700 m 763 m/s 61 mm,
800 m 717 m/s 52 mm.

800 meters was the greatest distance Pzgr. 40/1 should be fired, 600 meters Pzgr.40.

(At 100 meters 1135 m/s, Pzgr.40 officially perforated 130 mm with 30 degree deflection.)

The British Ordnance Board's December 15,1943 Curve OB/43/CV 23 shows Pzgr.40. With a velocity of 1135 m/s against UK plate it had 152 mm CV penetration at 0 degrees, 123 mm at 30 degrees deflection.
I always wondered what the penetration criteria for the tungsten rounds was. It must have differed from the APCBCHE type rounds (GD and such). Tungsten has a habit of disintegrating when hitting pretty much anything. One could stipulate a weight and perhaps velocity? Obviously, they are in no condition to "explode". Since the British 'CV' for PzGr. 40 is less at 100 meters, than the Krupp numbers, it sort of implys another factor is at work.

What armor types were used by German (homog.?) and maybe harder steel by the British? In some ways, the armor type might not matter.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Miles Krogfus » 12 Jun 2015 00:24

Total Krupp production of all tungsten cores:
15 dia. 58 mm length for 42 mm Pzgr 41: 424,205
16 dia. 58 mm length for 37 mm Pzgr 40: 1,931,737
21 dia. 75 mm length for 50 mm Pzgr 40 and 40/1: 1,911,102
28 dia. 110 mm length for 75 mm Pzgr 40, 75 mm Pzgr 41, 76.2 mm Pzgr 40: 193,040
30 dia. 120 mm length for 75 mm PzGr 40, 88 mm Pzgr 40: 24,359
36 dia. 140 mm length for 88 mm Pzgr 40: 39,485
German test plate hardness 90-120 mm HB 275-302, 130-150 mm HB 234-261, 160 mm+ HB 207-234.
British test plate hardness: I'll look up these figures this weekend . . .
Russian APCR was inferior to American, British and German since it was more brittle per Rockwell C hardness, and more porous, thus had to be heated to a lesser hardness and fired at lower muzzle velocities. Also Russian APCR was smaller per mm of guns firing it, and so also weighed less.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 12 Jun 2015 05:35

Amazing. Did Krupp ship manifacture out to sub-contractors or smaller companies and/for projectile assembly? I can't imagine it being one location.

I note that the 5,0 cm projectiles all went through a few iterations...

The 5,0 cm PzGr had a solid core type (probably the first type?), along with a 'V' version that had a two part construction (but AP). The PzGr 39 seems to be the 'V' version with a cap. 5,0 cm PzGr 42 seems to have a ballistic cap and also a different designed 'step' cap.

The PzGr 40 and PzGr 40/1 also had two Ausfuhrung sub-types each. It seems the same tungsten core with different carrier designs.
Screenshot 2015-06-11 22.14.46.png
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Yoozername
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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 12 Jun 2015 18:39

Miles Krogfus wrote:Total Krupp production of all tungsten cores:
15 dia. 58 mm length for 42 mm Pzgr 41: 424,205
16 dia. 58 mm length for 37 mm Pzgr 40: 1,931,737
21 dia. 75 mm length for 50 mm Pzgr 40 and 40/1: 1,911,102
28 dia. 110 mm length for 75 mm Pzgr 40, 75 mm Pzgr 41, 76.2 mm Pzgr 40: 193,040
30 dia. 120 mm length for 75 mm PzGr 40, 88 mm Pzgr 40: 24,359
36 dia. 140 mm length for 88 mm Pzgr 40: 39,485
German test plate hardness 90-120 mm HB 275-302, 130-150 mm HB 234-261, 160 mm+ HB 207-234.
British test plate hardness: I'll look up these figures this weekend . . .
Russian APCR was inferior to American, British and German since it was more brittle per Rockwell C hardness, and more porous, thus had to be heated to a lesser hardness and fired at lower muzzle velocities. Also Russian APCR was smaller per mm of guns firing it, and so also weighed less.
The Panther round should be 7,5 cm PzGr 40/42

30 dia. 120 mm length for 75 mm PzGr 40/42, 88 mm Pzgr 40: 24,359

The 24,359 is for both the Tiger I and Panther gun. How many were actually completed as projectiles, and then into cartridges is a very small number. And with the possibility of recall, the number actually fired is extremely small. Basically, it is almost not a battle round.

The PAK 40 also had very small numbers of PzGr 40 completed for its cartridge case. The KWK 40 weapons actually had more. So did the 7,62 cm weapon. Perhaps the PAK 40 had superior velocity for its PzGr 39and it was deemed more capable?

There are reports of these tungsten rounds having problems also with extraction.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Miles Krogfus » 13 Jun 2015 02:10

Three Krupp plants produced cores of all sizes, as in 1940 Essen 155, Bremen 355, Wuppertal 172 British tons, 1941 E 120, B 227, W 240 tons,
1942 E 139, B 220, W 70 tons, 1943 E 109, B 39, W 26 tons. In 1941-42 part of the ammo core capacity was switched over to production of tool tips.
Of the total core output of 2,590 Br. tons, 1,000 tons were sent to Borchers for Tungsten recovery, also small cores were used to create larger ones.
Some 250 tons of cores and tool tips were stored at the Braunesumpf mine. Various plants produced Pzgr 40/41 round carriers.

British test armor plate hardness figures:
5-15 mm Homo Hard HB 444-495, Machinable quality HB 340-388
16-30 mm Tanks HB 262-321, Armored Cars HB 342-388
35-80 mm HB 262-321
85-120 mm HB 255-302
125-160 mm HB 241-285
February 1944 Plate Hardness Figures:
Beardmore produced 50 and 60 mm plate of HB 262-269 for 2 and 25 Pounder tests.
Hadfield 50 mm HB 262-285 for 40 mm AP and 25 Pounder tests
Beardmore, E.S Company Ltd., Colvilles 70 mm of HB 272-273 for 6 Pounder AP
E.S. Company Ltd. 80 mm of HB 304 for 6 Pounder APCBC
Beardmore 100 mm of HB 248-258 for 17 Pounder AP
Firth Brown 120 mm HB 273-275 for 17 Pounder APC, HB 285-290 for 3.7 AP

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Re: Pak 38 Pzgr.40 and 40/1

Post by Yoozername » 13 Jun 2015 02:52

From another thread...

Here is a 'snap shot' of German ammunition inventory (x1000) as far as 7,5 cm ammunition in late 1942. This is from the Axis History site:
x1000

50 mm
Sprgr Patr 38 (5 cm Kw K): 1975.4
Pzgr Patr (5 cm Kw K) and Pzgr Patr 39 (5 cm Kw K): 1950.1
Pzgr Patr 40 (5 cm Kw K): 416.3
Sprgr Patr 38 (5 cm Kw K 39 L/60): 835.2
Pzgr Patr 39 (5 cm Kw K 39 L/60): 960.7
Pzgr Patr 40 (5 cm Kw K 39 L/60): 58.4
5 cm Sprgr Patr 38 (Pak 38): 1093.7
5 cm Pzgr Patr (Pak 38) and 5 cm Pzgr Patr 39 (Pak 38): 1627.3
5 cm Pzgr Patr 40 (Pak 38): 383.4
5 cm Stielgr 42: 0

75 mm

7,5 cm Kw K (all ammunition types): 2841.5
7,5 cm Sprgr Patr 34 (7,5 cm Kw K 40 and Stu K 40): 498.4
7,5 cm Gr Patr 38 Hl (7,5 cm Kw K 40 and Stu K 40): 412.8
7,5 cm Pzgr Patr 39 (7,5 cm Kw K 40 and Stu K 40): 747.6
7,5 cm Pzgr Patr 40 (7,5 cm Kw K 40 and Stu K 40): 22.1
7,5 cm Gr Patr Nb (7,5 cm Kw K 40 and Stu K 40): 22.6
7,5 cm Sprgr Patr 42 (7,5 cm Kw K 42): 458.8
7,5 cm Pzgr Patr 39/42 (7,5 cm Kw K 42): 341.9
7,5 cm Pzgr Patr 40/42 (7,5 cm Kw K 42): 3.1
7,5 cm Sprgr Patr 34 (7,5 cm Pak 40): 533.1
7,5 cm Gr Patr 38 Hl (7,5 cm Pak 40): 917.6
7,5 cm Pzgr Patr 39 (7,5 cm Pak 40): 945.3
7,5 cm Pzgr Patr 40 (7,5 cm Pak 40): 1.7
7,5 cm K Gr rot Nb (7,5 cm Pak 40): 30.3
7,5 cm Sprgr Patr 41 (7,5 cm Pak 41): 25.2
7,5 cm Pzgr Patr 41 H K (7,5 cm Pak 41): 63.3
7,5 cm Pzgr Patr 41 St K (7,5 cm Pak 41): 0
7.5 cm Pzgr Patr (W) (7,5 cm Pak 41): 0
Sprgr Patr für Pak 97/38: 5612.9
7,5 cm Gr Patr Hl für 7,5 cm Pak 97/38: 1464.9
7,5 cm Rf K 43: 0



Another 'snap-shot' (tungsten) a year later...

Some storage numbers to get an idea about the German supply situation.

December 1943:
680,000 3.7 cm Pzgr. 40 for the 3.7 cm Pak and about 269,000 3.7 cm Pzgr. 40 for the Kw.K.
207,000 5 cm Pzgr. 40 and 40/1 for the 5 cm Pak 38.
298,000 5 cm Pzgr. 40 and 40/1 for the 5 cm Kw.K. (L/42).
32,000 5 cm Pzgr. 40 and 40/1 for the 5 cm Kw.K. 39 (L/60).
About 15,000 7.5 cm Pzgr. 40 for the 7.5 cm Kw.K./Stu.K. 40.
55,000 7.5 cm Pzgr. 41 (H.K.) for the 7.5 cm Pak 41.
60,000 7.6 cm Pzgr. 40 for the 7.6 cm Pak.

Sources claim that PAK 40 Pzgr 40 manufacture was not only low in 1942, but had stopped entirely in 1943. They also claim that KWK40/StuK40 did not stop, and they might have continued after 1943 for awhile. 88mm, 75mmL70, and some other completely stopped in 1943.

A PAK 40 Pzgr 40 may be an extremely rare item. The PAK 40 actually had a rather large number of HEAT rounds made.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Peasant » 28 Nov 2018 09:12

I have built an external ballistics model from those data points and extrapolated the PzGr.40/1 terminal velocities at various ranges:
  • Range (m) (m/s)(fps)
  • 0 1180 3869
  • 100 1120 3672
  • 200 1062 3482
  • 300 1006 3299
  • 400 952 3123
  • 500 901 2953
  • 600 851 2790
  • 700 803 2633
  • 800 757 2483
  • 900 713 2338
  • 1000 671 2200
  • 1100 630 2067
  • 1200 592 1940
  • 1300 555 1819
  • 1400 519 1703
  • 1500 485 1592
  • 1600 453 1486
  • 1700 422 1385
This model work only for objects in supersonic flight, so cant calculate under approx 400m/s

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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 28 Nov 2018 14:57

Peasant wrote:
28 Nov 2018 09:12
I have built an external ballistics model from those data points and extrapolated the PzGr.40/1 terminal velocities at various ranges:
  • Range (m) (m/s)(fps)
  • 0 1180 3869
  • 100 1120 3672
  • 200 1062 3482
  • 300 1006 3299
  • 400 952 3123
  • 500 901 2953
  • 600 851 2790
  • 700 803 2633
  • 800 757 2483
  • 900 713 2338
  • 1000 671 2200
  • 1100 630 2067
  • 1200 592 1940
  • 1300 555 1819
  • 1400 519 1703
  • 1500 485 1592
  • 1600 453 1486
  • 1700 422 1385
This model work only for objects in supersonic flight, so cant calculate under approx 400m/s
It's better to start with actual data and try to match that with your program output.
50mm/L60 APCR |0/1180 |100/1126 |400/972 |600/870 |800/780 ,

Peasant you obviously aren't using a ballistic program that employs the Garve drag curves. If you don't use the Robert McCoy formulas there is the program here that seems pretty good. You would have to translate it from BASIC to your favorite code.
https://www.tapatalk.com/groups/warship ... 36818.html

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Re: Pak 38 Pzgr.40 and 40/1

Post by Peasant » 28 Nov 2018 20:50

Mobius wrote:
28 Nov 2018 14:57
Peasant you obviously aren't using a ballistic program that employs the Garve drag curves. If you don't use the Robert McCoy formulas there is the program here that seems pretty good. You would have to translate it from BASIC to your favorite code.
https://www.tapatalk.com/groups/warship ... 36818.html
I am not using any specific ballistic program at all. I'm using this model http://mathscinotes.com/2011/01/modelin ... sus-range/ and so far it proved to be able to describe the range/velocity for a large variety of calibers and nose shapes. Once I find a number of terminal velocities at various ranges, I'm using Excel Solver tool to fit the n-exponent and extrapolate the rest.
Mobius wrote:
28 Nov 2018 14:57
It's better to start with actual data and try to match that with your program output.
50mm/L60 APCR |0/1180 |100/1126 |400/972 |600/870 |800/780 ,
Well, I wont turn the help when offered, but I'd like to know where this data comes from? "Handbuch der Flugzeug Bordwaffenmunition" has a lot of velocity tables, including those for 5cm PzGr.39 and Sprgr.38 but no data for either Pzgr.40 or 40/1.
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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 29 Nov 2018 03:32

I haven't been able to track down where it came from. I thought it was from an old Lorrin Bird post but it is not the case.

But, a better way to track it is to go by TOP of the Krupp core penetration velocities. So at 500m the Pzgr. 40/1 is 76mm while the Pzgr. 40 is 72mm.
So the velocity of the pzgr. 40 would be about 836 m/s. However, these tables don't often follow the rules. I mean if 1180m/s MV supposedly penetrates 130mm at 100m (1135m/s) while a 1130 m/s MV penetrates 113mm at 100m (1074m/s ) (a difference of 17mm). With a 61 m/s difference in strike velocity. How does a 50m/s loss in velocity between 100m and 200m lose only 10mm of penetration? And who can explain the pzgr. 40/1 losing 56m/s the first 100m while the pzgr. 40 losing only 45? Unless there are some very unstable flight characteristics.

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Re: Pak 38 Pzgr.40 and 40/1

Post by Miles Krogfus » 29 Nov 2018 17:52

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

Post by Peasant » 30 Nov 2018 02:08

Mobius wrote:
29 Nov 2018 03:32
I haven't been able to track down where it came from. I thought it was from an old Lorrin Bird post but it is not the case.

But, a better way to track it is to go by TOP of the Krupp core penetration velocities. So at 500m the Pzgr. 40/1 is 76mm while the Pzgr. 40 is 72mm.
So the velocity of the pzgr. 40 would be about 836 m/s. However, these tables don't often follow the rules. I mean if 1180m/s MV supposedly penetrates 130mm at 100m (1135m/s) while a 1130 m/s MV penetrates 113mm at 100m (1074m/s ) (a difference of 17mm). With a 61 m/s difference in strike velocity. How does a 50m/s loss in velocity between 100m and 200m lose only 10mm of penetration? And who can explain the pzgr. 40/1 losing 56m/s the first 100m while the pzgr. 40 losing only 45? Unless there are some very unstable flight characteristics.
Let's address the problems one at a time.
The penetration performance: I've noticed that these two values are located above and below from 120mm. What's so special about it, you might ask? Well, this was the point where german testing plate switches tensile strength specs from those used for 80-120mm to 120-150mm, becoming softer. This might account for a sudden increase in penetration. You can see it happening between 400 and 500m where the shell suddenly starts to penetrate less at around 80mm. Cant explain that last data point at 800m though.

I dont think I have those PzGr.40 ballistic tables you are referring to. This is very strange indeed. It would help if I could see the said table, before making theories.
Miles Krogfus wrote:
29 Nov 2018 17:52
Pak 38 Pzgr 40/1:
Thank you, I havent seen that table before.
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Mobius
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Re: Pak 38 Pzgr.40 and 40/1

Post by Mobius » 30 Nov 2018 02:31

I've tried to work out the ballistics of pzgr. 40 from the posted penetrations. I would prefer an actual firing table. I'm hoping Miles has a dusty copy of it somewhere. :)
But speaking of actual data I've been noticing that English Wikipedia gun data is been taken over by Bird and Livingston calculated data. (Luckily Russian wiki still uses Russian official data on Russian guns.)

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