Yu guns vs armor tests of 1960s...

[bojan]

Positioning of recoil buffers on gun and gun mounting itself has a lot to do with dispersion.

[Mobius]

Thanks Bojan!

 

 

Mobius, do your data apply to combat shooting or to shooting under laboratory conditions? I would expect that under laboratory conditions Y and X dispersion would be roughly equal, but that in combat Y dispersion would be much greater due to range estimation errors.

I suppose it is all laboratory tests. Most are from US, UK, and German sources about mean dispersion. So is probably derived combining of many test shoots of several guns.

I do have tests from 1944 University of New Mexico tests where some individual shoot tests of 6-12 shots have more dispersion in the horizontal than vertical direction. On balance they seem to collectively average to a higher vertical dispersion.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA800118

The Soviet test seems to be from one particular gun.

Edited March 31, 2013 by Mobius

[bojan]

5cm PaK38 vs T-34/85

 

 

M39 AP penetrates upper front hull @ 100m

M40/1 subcaliber penetrates upper front hull @ 400m

 

 

M39 AP penetrates upper side hull @ 500m

M40/1 subcaliber penetrates upper side hull @ 750m*

 

 

M39 AP penetrates lower side hull @ 750m*

M40/1 subcaliber penetrates lower side hull @ 750m*

 

 

M39 AP fails to penetrate front turret @ 100m

M40/1 subcaliber penetrates front turret @ 200m

 

 

M39 AP fails to penetrate side turret @ 100m

M40/1 subcaliber penetrates side turret @ 500m

 

 

M39 AP penetrates rear turret @ 500m

M40/1 subcaliber penetrates rear turret @ 750m*

 

 

5cm PaK 38 vs M4A3E4:

 

 

M39 AP penetrates upper front hull @ 150m

M40/1 subcaliber penetrates upper front hull @ 500m

 

 

 

M39 AP penetrates side hull @ 750m*

M40/1 subcaliber penetrates side hull @ 750m*

 

 

 

 

M39 AP fails to penetrate front turret @ 100m

M40/1 subcaliber penetrates front turret @ 250m

 

 

 

M39 AP penetrates side and rear turret @ 750m*

M40/1 subcaliber penetrates side and rear turret @ 750m*

 

*Max range of tests.

Edited April 3, 2013 by bojan

[Marek Tucan]

Nice, thanks!

The Shermans were late production with single-piece glacis, would be interesting to have somewhere firing trials of 5cm PaK against the early model

[Mobius]

You'd think the AP would penetrate the side turret of the T-34 a little better.

[Marek Tucan]

Probably combination of overmatch (or lack thereof) and pretty hard armor - 76mm @ 20° is pretty pushing it, given that the usual German data for PzGr.39 are something like 69mm @ 30° @ 100m. Of course there are different test standards, but I find it pretty believable.

[Mobius]

Bojan, I was reviewing the data and found this "57mm M1 ATG, firing AP round penetrates T-34/85 front (no clarification if it is hull or turret) @ 320m and M4A3E4 Sherman front (no clarification if it is hull or turret) @ 400m." Is that the US 57mm, British 6pdr or ZiS-2?

[Lieste]

M1 suggests LL ~ 57mm and 6pdr are the same weapon though I thought...

[bojan]

Bojan, I was reviewing the data and found this "57mm M1 ATG, firing AP round penetrates T-34/85 front (no clarification if it is hull or turret) @ 320m and M4A3E4 Sherman front (no clarification if it is hull or turret) @ 400m." Is that the US 57mm, British 6pdr or ZiS-2?

 

US or UK 57mm/6pdr, L/52, both were used locally under the same "Anti-tank(armor) gun 57mm M1" ("Protiv-oklopni top 57mm M1") designation.

Data for ZiS-2 was posted, for both Sherman and T-34

[Mobius]

Just to review. Going by the gun penetration curves. The US/UK 57mm/L52 penetrates the T-34/85 turret at 320m which is ~95.0mm. It penetrates the M4E3A4 turret at 400m which would be ~93.0mm. The 57mm ZiS-2 only penetrates the T-34/85 turret at 600m which is ~100.0mm level. It penetrates the M4E3A4 turret at 900m which would be ~93.5mm. The 50mm/L60 doesn't ever reach the 93mm penetration level.

Edited April 4, 2013 by Mobius

[bojan]

...The 50mm/L60 doesn't ever reach the 93mm penetration level.

Well, that was well known, 5cm PaK could not penetrate KV-1 sides (75mm) and had to use PzGr.40 to be able to cope with those.

[Mobius]

In the 1950s the US measured the BHN of glacis armor of the T-34/85 as 429. The turret as 444.

[Loopycrank]

Positioning of recoil buffers on gun and gun mounting itself has a lot to do with dispersion.

 

I had heard that before, especially in conjunction to the change to concentric recoil systems, but I had never heard any specifics.

 

Also, Bojan continues to deliver in this thread!

 

 

Thanks Bojan!

 

 

Mobius, do your data apply to combat shooting or to shooting under laboratory conditions? I would expect that under laboratory conditions Y and X dispersion would be roughly equal, but that in combat Y dispersion would be much greater due to range estimation errors.

I suppose it is all laboratory tests. Most are from US, UK, and German sources about mean dispersion. So is probably derived combining of many test shoots of several guns.

I do have tests from 1944 University of New Mexico tests where some individual shoot tests of 6-12 shots have more dispersion in the horizontal than vertical direction. On balance they seem to collectively average to a higher vertical dispersion.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA800118

The Soviet test seems to be from one particular gun.

 

 

Very interesting, thank you!

[bojan]

In the 1950s the US measured the BHN of glacis armor of the T-34/85 as 429. The turret as 444.

WW2 production or later, and which factory if known? I will try to chase down, but IIRC most of local WW2 vintage T-34-85 were made by No.112 factory.

[Mobius]

 

In the 1950s the US measured the BHN of glacis armor of the T-34/85 as 429. The turret as 444.

WW2 production or later, and which factory if known? I will try to chase down, but IIRC most of local WW2 vintage T-34-85 were made by No.112 factory.

Oh, I don't know. The text says it is from a number of them recovered on German battlefields after WWII and the battlefields of Korea.

 

But, reading through the text those numbers could be from the sample T-34 sent in 1943. It doesn't say if it is a T-34/76 or T-34/85. It does say both types were obtained. And the thickness was 3.25" so I assume it was a T-34/85.

Edited April 5, 2013 by Mobius

[Mobius]

Kind of odd that the Soviets APCR data doesn't agree with itself in these two documents of the 5.0cm Pak 38.

[bojan]

Mobius, Soviet data is for PzGr.40, Yu data is for PzGr.40/1.

[Mobius]

Mobius, Soviet data is for PzGr.40, Yu data is for PzGr.40/1.

What is that?

[Marek Tucan]

40/1 was sort of optimised 40 IIRC, heavier and slower, but keeping penetration better over distance. Maybe using less tungsten?

 

As for data in your image, different test criteria probably, plus might be difference between projectiles used.

[bojan]

Mobius, What Tuccy wrote, there were two APCR designs for 5cm PaK, PzGr.40 and PzGr.40/1, later being heavier, and penetrating somewhat less at short range but keeping penetration better.

[Mobius]

There is mention that the Germans changed the design of their PzGr.40 of 75mm guns from the
arrowhead type to something more akin to the US HVAP design.

I haven't found anything other then the arrowhead type to have been used for the 3,7cm and 5cm
guns. But as you say the Yugoslavs did had a later design, the 40/1.

[bojan]

BTW, 5cm PaK was retired in 1961* so tests were done before that.

*OFC, it was in storage forever, probably until mid-late '70s at least.

[Mobius]

BTW, 5cm PaK was retired in 1961* so tests were done before that.

*OFC, it was in storage forever, probably until mid-late '70s at least.

 

Over here they rent them to the movie industry. The owner of a PaK 35/36 said it was worth $100,000 !!!! and that was about 10 years ago.

[Przezdzieblo]

For 5 cm cored projectiles, see pages 17 and 18 of this PDF. PzGr. 40 was arrowhead APCR, Pzgr. 40/1 was fully-body APCR, although much different than US designs.

[Marek Tucan]

Interesting find, Przezdzieblo, the 5cm PzGr.42 looks like a nice little APCBC - was it ever issued?

The PzGr. 40 for 7.5cm seems to take after 5cm PzGr.40/1, so already with the streamlining in place.

 

I see there also 8.35cm PzGr. I am very interested in... For Czechoslovakian 83.5mm AA gun I presume.

 

I didn't know the 8.8cm PzGr. was APCBC either.