Vulnerability of the Panther Glacis to 122 AP

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Re: Vulnerability of the Panther Glacis to 122 AP

#31

Post by Mobius » 29 Mar 2020, 06:20

Yeah, I reverse calculated those penetration numbers to get velocities using DeMarre and didn't get a very reasonable ballistics curve for an ogive shaped shell. In fact the BR-540 for the ML-10 @ 560 m/s produces realistic numbers. The ML-20 BR-540 at 600 m/s does not.

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Re: Vulnerability of the Panther Glacis to 122 AP

#32

Post by Contender » 29 Mar 2020, 09:57

Miles Krogfus wrote:
29 Mar 2020, 03:51
During WW II the JSU152 also only used the sharp nose AP not the B model.
Thank you very much I suspected this for a very long time... :)


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Re: Vulnerability of the Panther Glacis to 122 AP

#33

Post by Peasant » 29 Mar 2020, 18:33

Miles Krogfus wrote:
28 Mar 2020, 02:02
These FT were issued 27 July 1944 while the report I've posted is dated 15/03/1945, there was still time for the newer shells to reach the front.

I've been trying to track down the production statistics of the artillery shells in soviet factories during the war but most of the sources just say "122mm AP shells" if they even make the distinction between different calibers and HE/AP shells at all.

Found this though:
Более эффективен тупоголовый бронебойный снаряд с баллистическим наконечником БР-471Б с такой же массой, как и все остальные, – в четверть центнера. Снаряд содержал заряд взрывчатки «А-IX-2». Он был разработан в том же 1944 году. БР-471Б был лишен этого недостатка, однако в войсках в массовых количествах он появился только уже в самом конце войны – весной сорок пятого.
The more efficient blunt headed shell with ballistic screen BR-471B ... appeared in serious numbers among the frontline troops only in the spring of 1945.
from the book of a russian historian G. Saviczkij Tank, "Josif Stalin"

For the sharp tipped 122mm shells to be able to achieve penetrations against Panther UFP at 1300m(622m/s) it would have to have <75mm of effective thickness, which is... not outside the realm of possibility, if the said encounters took place during the winter of 1944/1945 and the Panther armour behaved anything like that of the Tiger II under cold weather conditions.

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Re: Vulnerability of the Panther Glacis to 122 AP

#34

Post by Contender » 29 Mar 2020, 18:55

Peasant wrote:
29 Mar 2020, 18:33
BR-471B ... appeared in serious numbers among the frontline troops only in the spring of 1945.
from the book of a russian historian G. Saviczkij Tank, "Josif Stalin"
Isn't this the usual back and forth with this round? A sentence that claims it was used in WWII and an almost identical sentence in another book that contradicts the claim. Here is the contradicting statement from another russian book:
-The blunt nosed armour-piercing BR-471B- was developed in spring 1945 but only started entering heavy tanks' ammunition loads after the war had finished Page 32 The IS tanks By mikhail baryatinskiy

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Re: Vulnerability of the Panther Glacis to 122 AP

#35

Post by Peasant » 29 Mar 2020, 19:10

Contender wrote:
29 Mar 2020, 18:55
Peasant wrote:
29 Mar 2020, 18:33
BR-471B ... appeared in serious numbers among the frontline troops only in the spring of 1945.
from the book of a russian historian G. Saviczkij Tank, "Josif Stalin"
Isn't this the usual back and forth with this round? A sentence that claims it was used in WWII and an almost identical sentence in another book that contradicts the claim. Here is the contradicting statement from another russian book:
-The blunt nosed armour-piercing BR-471B- was developed in spring 1945 but only started entering heavy tanks' ammunition loads after the war had finished Page 32 The IS tanks By mikhail baryatinskiy
I am just playing devil's advocate with the other guy. After all, although I've said that its possible that these shells were used in combat units before the end of 1944 I have no proof other than indirect indications that this was the case.

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Re: Vulnerability of the Panther Glacis to 122 AP

#36

Post by Miles Krogfus » 29 Mar 2020, 20:57

WW II German and Allied armor veterans told me of weapons and ammunition that just reached them days before the war ended in the Spring of 1945 so were not employed in combat. Note that (1) the date contents of a Russian military manual were approved came earlier (2) than the date that manual was printed and (3) when it was later delivered to combat troops. Also, a manual arrived and the ammunition it discussed arrived at different times in various combat zones. Where is a primary document stating that the BR-471 B round was (1) obtained by a combat unit and/or (2) used in combat?

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Re: Vulnerability of the Panther Glacis to 122 AP

#37

Post by Peasant » 21 Apr 2020, 18:05

From the book "Танковая мощь СССР часть III Золотой век":

Image

Translation:
The ballistic trials on fully kitted samples of captured tanks with an IS-122 tank, from serial production batch, were conducted on the UZTM's firing range in January of 1944 and have demonstrated that the service 122mm shell reliably defeats the frontal armour of the "Panther" tank at range of 600-700m, while the improved armour piercing tracer shell with high explosive filler (manufactured from schematic No.2-2868 A) could do it from 1200-1400m, which is why on 15 of January NKB proceeded to setting up production facilities for this type of shell.
I've long wondered where does the figure "600-700m" come from. Its quoted on wikipedia but no source is listed.
I understand that setting up new production lines takes time, but if it started since almost the beginning of 1944...

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Re: Vulnerability of the Panther Glacis to 122 AP

#38

Post by Contender » 21 Apr 2020, 20:05

Peasant wrote:
21 Apr 2020, 18:05
I've long wondered where does the figure "600-700m" come from. Its quoted on wikipedia but no source is listed.
I understand that setting up new production lines takes time, but if it started since almost the beginning of 1944...
The 600-700 meter figure is also in the "contrary statement" book above, it claims its from a Kubinka 1944 test no further details. It also give the 1200 meter range vs the Tiger I E.

I have long wondered who or what "soviet linemen™" are and why I should trust what these vague group of people say more than any other anecdotal account or hearsay. Rexford & the book I quoted above seem to believe in them as a source however.....

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Re: Vulnerability of the Panther Glacis to 122 AP

#39

Post by Peasant » 14 May 2020, 15:29

Found this. No source, but it looks like a page from a bigger document:

Image

Translation:

Table No.15

Firing Trials on the hull of a "Panther" tank.

Shot No. 1
Shell type: AP.
Target: Turret.
Armour thickness( in mm): 45
Obliquity(in °): 28
Angle between the direction of firing and the hull( in °): 90
Distance( in m.): 1000
Damage to the target: "Hole through. A piece of armour, 120mm in diameter thrown from the back of the plate. Inside, breech of the gun badly damaged."

Shot No. 2
- same stuff -
Damage to the target: "Hole through. The shell went into the gun mantlet 100mm thick. There it made a deep dent with a crack through"

Shot No. 3
- same stuff -
Damage to the target: "Hit to the corner of the turret. Hole through. A piece of armour, 120x130mm thrown from the back of the plate"

Shot No. 4
Target: Front hull.
Armour thickness( in mm): 65
Obliquity(in °): 55
Angle between the direction of firing and the hull( in °): 90
Distance( in m.): 200
Damage to the target: "Hole through of size 170x190mm"

Shot No. 5
-- same --
Armour thickness( in mm): 85
--same--
Damage to the target: Dents 45 and 65mm deep.

Shot No. 6
-- same --
Distance( in m.): 400
Damage to the target: "Dent 45mm deep, size 100x170mm, cracks in the armour within this dent's area."

Shot No. 7
-- same --
Distance( in m.): 700
Damage to the target: "Dent 35mm deep, size 30x230mm"

Shot No. 8
Shell type: Subcaliber.
-- same --
Distance( in m.): 1000
Damage to the target: "Dent 30mm deep."

Shot No. 9
Shell type: AP.
-- same --
Armour thickness( in mm): 65
Damage to the target: "Breach 30x50mm. A piece of armour, 120x180mm thrown from the back of the plate"


Now, it doesn't say which weapon was used here but from the fact that it failed against the UFP at 200m and yet defeated the LFP at 1000m I believe it was the 85mm AA gun firing the BR-365( the one with a windshield) shell.

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Re: Vulnerability of the Panther Glacis to 122 AP

#40

Post by Yoozername » 14 May 2020, 22:32

Now, it doesn't say which weapon was used here but from the fact that it failed against the UFP at 200m and yet defeated the LFP at 1000m I believe it was the 85mm AA gun firing the BR-365( the one with a windshield) shell.
I would agree. There are many details that might be in other parts of that report. But the methodology seems to fire from close range and then further ranges. I would prefer the opposite. That is, fire at 1000 meters and then 700 m, etc.

In the case of the LFH, it was holed at 200 meters, perhaps damaging it so that the shot from 1000 meters "Breach 30x50mm. A piece of armour, 120x180mm thrown from the back of the plate". perhaps not a fair hit, but who knows? The first 'hole' was "Hole through of size 170x190mm"...that is a really big chunk of metal. Maybe that is measured on the inside of the armor?

Clearly not a 76mm weapon. And unlikely a 100 mm weapon either. I would expect a 200 meter shot to go through the UFH.

Why would they not fire the sub-caliber at a closer range? Especially since they did not penetrate the UFH? I believe that the 85mm APCR had a rather small penetrator, maybe one used in smaller calipers?

Good find.

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Re: Vulnerability of the Panther Glacis to 122 AP

#41

Post by Peasant » 13 Jun 2020, 12:45

Found some info, not on the 122mm but the 100mm:

Image
The armour strength of the T-54 Mod.1951 was somewhat weakened compared to that of the Mod.1948. Reminder: the frontal hull plates were reduced in thickness from 120mm to 100mm. While the 120mm armour was immune to the domestic 100mm D-10T gun, the results of the firing trials made in 1950 showed that the UFP was defeated by the blunt headed shell from a distance of 470m and the lower from 1000m. With an additional 20° side angle the distances are reduced to 240m and 790m respectively.
Source: book "C.Устьянцев, Д. Колмаков, Боевые машины УРАЛВАГОНЗАВОДА. Т-54/Т-55. 2004"

These results are quite bad. Compared to the British plate the UFP showed the effective thickness of just 86mm and the LFP of 92mm, assuming the "defeat" here means the PTP limit.

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Re: Vulnerability of the Panther Glacis to 122 AP

#42

Post by Peasant » 25 Jul 2020, 19:01

Code: Select all

80mm/55°
100mm BR-412: 1150m
100mm BR-412B: 2350m
122mm BR-471: 900m
122mm BR-471B: 1500m
I'm not sure how accurate these are, but it fits well with data collected so far.

Source on 6pdr AP: https://imgur.com/a/KkIPG9Q
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estimated protection limit for MQ RHA at 55°, estimated from 6pdr AP firing data.png

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Re: Vulnerability of the Panther Glacis to 122 AP

#43

Post by Contender » 27 Jul 2020, 03:47

Peasant wrote:
25 Jul 2020, 19:01
I'm not sure how accurate these are, but it fits well with data collected so far.
Looks good, idk about the 100 mm & I've not followed the conversation too closely but if I recall correctly Rexford (whatever happened to him?) might have posted something years ago to the effect that the 100mm would be more susceptible to the slope effects (vs Panther plate) than the 122mm so shouldn't the data between both the 122 & 100 mm weapons be closer together?
Do you have a table for the 85 mm vs 60mm @ 60 deg (vs Hetzer grade steel) I'm curious as to what kind of protection that vehicle would have vs that weapon as I've heard many conflicting arguments about it.

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Re: Vulnerability of the Panther Glacis to 122 AP

#44

Post by Peasant » 27 Jul 2020, 09:53

Contender wrote:
27 Jul 2020, 03:47
Peasant wrote:
25 Jul 2020, 19:01
I'm not sure how accurate these are, but it fits well with data collected so far.
Looks good, idk about the 100 mm & I've not followed the conversation too closely but if I recall correctly Rexford (whatever happened to him?) might have posted something years ago to the effect that the 100mm would be more susceptible to the slope effects (vs Panther plate) than the 122mm so shouldn't the data between both the 122 & 100 mm weapons be closer together?
Do you have a table for the 85 mm vs 60mm @ 60 deg (vs Hetzer grade steel) I'm curious as to what kind of protection that vehicle would have vs that weapon as I've heard many conflicting arguments about it.
"more susceptible"... relative to what might I ask? Both curves merely describe the behavior of british-type of shot at those obliquities and t/d ratios, they are no more no less distant than the data points obtained from 6pdr AP against 45mm plate(t/d = 0,8) and against 37mm plate (t/d = 0,66).

Hetzer's UFP was likely designed with the goal in mind of providing immunity to soviet 57mm ZiS-2 ATG up to point blanc. which it likely was, assuming good material quality. But 85mm gun was a more serious threat, the Army limit for this target would be between 725 - 787m/s, or between 200-700m, for the 85mm shell with the windscreen.

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Re: Vulnerability of the Panther Glacis to 122 AP

#45

Post by Peasant » 29 Jul 2020, 19:36

I had an idea: it is likely that by 1943/44 german engineers have already determined the anti-armour capabilities of all soviet guns encountered so far from testing of the captured pieces, therefore it is reasonable to assume that certain areas of Tiger II armour layout were designed with the goal of protecting the vehicle from hits of 122mm soviet guns at 100m.
Using the turret front of the late Tiger II turret and its LFP as the reference points, as well as some of the more arcane terminal ballistic knowledge I've obtained by means that shall be left unnamed, I've created this chart.

Edit: the frontal part of the turret roof (40mm/14°) fits perfectly into this model.
Attachments
Immunity curve for 122mm D-25T gun at 100m.png

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