7,5 cm Kwk/StuK/Pak 40 Firing Table Data

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whelm
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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by whelm » 11 Nov 2016 19:09

Here's the majority of them I believe, you can see how it changes by date and the later ones always supersede the older.

14.81 lb from the Kwk 37
May 1943
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15 lb from the kwk 37
Dec 1943
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14.81 lb from Kwk 40
May 1943
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15 lb from L/70, Pak and Kwk 40
Dec 1944
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15 lb from L/70, Pak and Kwk L/48 and L/43
Dec 1945
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Various
Image

whelm
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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by whelm » 11 Nov 2016 19:34

And for an interesting look at what the 75mm Pzgr 39 was capable of compared to the US 75mm.

The us did a number of firing tests to compare 90mm to 88mm rounds, and 75mm to 75mm rounds.

They mated the US 75mm rounds to German powder and fired them out of a L/70

First report on armor penetration of German and American armor piercing projectiles
&
Twenty-fourth report on Ordnance program No. 5886


Dates of test Dec 1944 to Feb 1945

Conclusions:
The results of the tests conducted in this program indicate:
A. That the German projectiles had better penetration characterisitcs against homogeneous armor plate than the American Porjectiles.
B. That the German proctiles had less tendency to shatter when fired against homogenous armor plate at high velocities.

Recommendations:
It is recommend that the design features, hardness pattern and composition of the German armor piercing projectil;es be studied for purpose of improving American armor piercing ammunition.

Plate 217-230 BHN

Standard German 75mm APCBCHE round inert loaded
Standard US 75mm M61 inert loaded

German 75mm Fired against 127mm plate @ 30 and 45 deg
US 75mm fired against 127mm @ 30 deg

Ballistic limits
German 75mm
Army Navy Prot.
30d 2543 2734 2734
45d 3127 3127 3127

US 75mm
30d 3175* none none

*Partial penetraions. No ballistic limit could be obtained.

75mm M61 shattered when fired against a 5" plate at 30 deg obliquity, at velocities of 2966 fps and above.

All german 75mm projecticles except one remained intact at striking velocities up to 3269 fps.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Yoozername » 11 Nov 2016 20:01

Nice data...Thanks...I would like to see the reports if you can put them up..."They mated the US 75mm rounds to German powder and fired them out of a L/70"...WOW! First I have heard of this. I always wondered why they never tried the 7,5 cm Pzgr 39 on the sherman 75 or the 7,62 cm Pzgr 39 rot on a US 3 inch or 76mm weapon...

As far as the actual document from the OP, H.Dv. 119/324 edition dated October 1944, it occurs to me that something is possibly wrong in the title itself, that is; What about the Pak 39?

The Jagdpanzer IV and Hetzer are both armed with this weapon and had been fielded before October 1944, so given that the KWK 40 and StuG 40 used the same ammunition as the Pak 39, why is it not included?

Why is the Pak 40 included? It is a antitank gun and SP (Marder) type weapon? It does not share ammunition with the KWK 40 or Stug 40 either?

It may eb that the document does cover the Pak 39 but mispelled it Pak 40 in the title.

whelm
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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by whelm » 11 Nov 2016 20:15

http://imgur.com/a/3PcXi

Image

Recall they were firing German 75mm ammo out of the M2/M3 in Africa, so no reason the opposite wouldn't have worked.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Yoozername » 11 Nov 2016 20:29

Yes, that's true but they did have to turn down (machine a bit) the German projectiles in North Afrika. These projectiles were the early large cavity 7,5 cm also. And they still performed very good compared to US ammunition.

Edit: The allies certainly captured weapons and stocks of ammunition in Normandy. Why they never made a SP version of the Pak 40, using older 'Stuart' or even M5 tanks, to create a Marder type system is beyond me. And, as far as I know, they never tested 7,5 cm Pzgr 39 projectiles on the Sherman 75,, or the 7,62 cm Pak 36 projectiles in the US 3 inch or 76mm weapons.

I have read of a Pak 40 that was captured in Normandy with a cartridge jammed in the gun. On closer inspection, it was found to be a 7,62cm Pak 36 round. Whether it was loaded out of ignorance or desperation know one knows.
Last edited by Yoozername on 12 Nov 2016 20:20, edited 1 time in total.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Yoozername » 12 Nov 2016 20:01

whelm wrote:
15 lb from L/70, Pak and Kwk L/48 and L/43
Dec 1945
Image

Various
Image
The "various" appears to be, left to right, 7,5cm Pzgr 39@ 2400ft/s, 7,5cm Pzgr39 @2800ft/s, Pak 41 (squeeze gun), 50mm Pak AP, KWK 50mm Pzgr 40, 88mm Flak 36 APCBC, and a 7,62 cm Pak 36 firing Pzgr 40.

I would expect them to be using standard US test Armor and it says 50% success criteria. Very interesting to compare with other data.
Last edited by Yoozername on 12 Nov 2016 20:23, edited 1 time in total.

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Mobius
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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Mobius » 12 Nov 2016 20:14

Yoozername wrote:
whelm wrote:
15 lb from L/70, Pak and Kwk L/48 and L/43

Various
Image
The "various" appears to be, left to right, 7,5cm Pzgr 39@ 2400M/s, 7,5cm Pzgr39 @2800M/s, Pak 41 (squeeze gun), 50mm Pak AP, KWK 50mm Pzgr 40, 88mm Flak 36 APCBC, and a 7,62 cm Pak 36 firing Pzgr 40.

I would expect them to be using standard US test Armor and it says 50% success criteria. Very interesting to compare with other data.
Isn't that British O.B. partial penetration criteria, not US Naval Limit? So the armor would likely be M.Q. not 237 BHN armor.
The 50mm AP40 with MV=3440 f/s is for a 50mm/L42 gun.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Yoozername » 13 Nov 2016 00:27

I believe we agreed that 'OB' were British tests and data. But it seems the one test recommendations type is from a US document. I want to know where the hand written document is from?

Note there is a line 'source of data' in the handwritten data page. It seems to look like a mix of sources. Some appear to say OB.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by whelm » 13 Nov 2016 03:08

Canadian or British I believe, these are all from Canadian microfilms, and it has a mix of Canadian, British and some American files in them.

Same with the hand written one, data changes at different dates all the time either as things were previously estimates and newer ones are using hard data from actual firing tests, the type of plate they test on changes, or the stock of ammo they are using changes.

July 1943
Image
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1943
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Feb 1944
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Dec 1944 or 45

Image


I have tables like the first one's for the 75mm for various other rounds like the 2pdr, 6 pdr, 17 pdr at differing dates as well somewhere.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Yoozername » 13 Nov 2016 03:58

Nice stuff. I will gorge...

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Mobius » 13 Nov 2016 16:27

These are great. But I'll have to look up the British/Canadian definition of perforation.

whelm
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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by whelm » 13 Nov 2016 16:38

Mobius wrote:These are great. But I'll have to look up the British/Canadian definition of perforation.
Late 42 or sometime in 43 I believe they switched from an 80% chance to a 50% chance in testing/calculations.

Image



now if that was an 80% chance for all or most of the projectile to penetrate, or something lower I can not recall. I think (But am not postive) when they switched to the 50% standard it was basically the same as the US.

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Mobius » 13 Nov 2016 18:08

The 50% standard was what it was called, but for the US it was an average of the highest partial penetration and lowest complete penetration. The British 50% standard was the highest partial penetration. (The US complete penetration was in fact 51% or more of the mass passing through the armor, so it was more like 50% of 50%.)

I wonder why the 17pdr APCBC penetration at 2000 yds. was 107mm in 2/1944 and 112mm in 12/1944?

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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by Yoozername » 14 Nov 2016 20:00

This is a cut from the last chart. I take it to be, left to right, the 7,5cm KWK L43 (possibly using Fur Tropen ammunition), Pak 40 792 M/s, Panther KWK L70 firing APCBC, Panther KWK L70 firing the Pzgr 39/42 tungsten carbide, Squeezebore Pak 41.

In the remarks, they seem to be referencing a test procedure. Note that some remarks are "OB est", perhaps an estimation? Note that one of these has the Pak 40 @ 2830 Ft/s! A little high even I woudl say.
75OB.jpg
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whelm
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Re: 75 mm Kwk/StuK/Pak 40 Firing Table Data

Post by whelm » 14 Nov 2016 21:05

Yes I believe est is short for estimate.

When it has a digit code for a source I assume then it's hard data from firing tests.

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