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90mm M3 and 88mm L/71


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#1 theHammer

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Posted 21 August 2009 - 1657 PM

I recently tripped over a thread on another forum discussing the 88mm L/71 German and 90mm M3 American WW II AT. One poster was apparently celebrating the omnipotence of the German 88. One reply went as follows:

"Postby Ultramagnus on 08 Aug 2004, 19:07

Here is calculated vertical penetration data against US test armor for both american andgerman guns.The equation is the De Marre used the author doubles Bird/Livingstone.

90mm M3 gun L/52 M82 APCBC-HE 2800 feet/sec(854m/sec) MV, penetration at 0 degree at 500 meters 164mm...151mm at 1000...138mm at 1500...127mm at 2000...169mm at 100 meters.

M3 gun M77 AP (no windscreen and ballistic cap,loses velocity quickly,shattering problems) 2700 feet/sec,163mm at 500...137mm at 1000...115mm at 1500...96mm at 2000...188mm at 100 meters

M3 gun T33 AP(BC) 2800 feet/sec,205mm at 500 meters...189mm at 1000...174mm at 1500 ...160mm at 2000 meters.

M3 gun M304 HVAP 3340 feet/sec, 278mm at 500...246 at 1000...218 at 1500...193mm at 2000 meters

88mm Kwk43 gun PzGr43 APCBC-HE 3280 feet/sec,219mm at 500...204mm at 1000...190mm at 1500...176mm at 2000 meters

Kwk43 gun PzGr40 APCR 3706/feet/sec,282mm at 500...257mm at 1000...234mm at 1500...213mm at 2000 meters.

It hasn't data for the T15 gun L/73 and T43 ammo for 975 M/sec or 3196 feet/sec.

The shorter M3 gun with T33 (no HE burster) owns 93% of the homogenous armor performance of the Kwk43 with Pzgr43 APCBC at 1000 meters and has to defeat lower effective armor when it is heavily sloped,remember this is the L/52 gun, but only 74% with M82 APCBC and 95% for the HVAP/APCR.

1.M3 gun T33 target 85/55 rolled homogenous armor plate,penetration 189mm,effective vertical thickness 183mm vs 90mm AP,slope multiplier is 2.15 (the same for M77 AP).Chance to penetrate 79% for 1.0328 ratio pen/armor

2.Kwk43 gun PzGr43 target same,penetration 204mm at 1000 meters,effective vertical thickness 214mm vs 88mm APCBC,slope multiplier is 2.51 Chance to penetrate 13%.for 0.953 ratio

3.122mm D25T gun blunt nosed APBC-HE target same ,slope multiplier is 1.713 effective armor thickness is 146mm only! Penetration at 1000 meters is 162mm only though but as you see it has to defeat less armor as well when it is sloped.But the Kwk43 penetrates much more vertical armor,indeed.On the thickness of the attacked armor/diameter of the projectile ratio counts also much (88mm/90mm vs 122mm),lower ratio-lower effective thickness,higher ratio-effective thickness etc.Caliber does matter.

BTW T33 projectiles were probably used only by the Zebra Mission tanks January on an experimantal basis, 1945 along.With supercharged M82 APCBC the M3 gun was roughly equivalent to the Kwk42 gun of the Panther,with normal M82 to the Kwk36 despite the higher kinetic energy of the 90mm (compared to Kwk36),the quality of the ammunition was not up to the german projectiles,again,except the T33 and maybe T43. :?

Ultramagnus

--http://forum.axishistory.com/viewtopic.php?f=47&t=56450&start=0"

What the pro 88 supporter got out of this was that the marginal superiority of the 88mm L/71 proved his point. What I took note of was "The shorter M3 gun with T33 (no HE burster) owns 93% of the homogenous armor performance of the Kwk43 with Pzgr43 APCBC at 1000 meters and has to defeat lower effective armor when it is heavily sloped,remember this is the L/52 gun, but only 74% with M82 APCBC and 95% for the HVAP/APCR."

I was impressed that ammo was developed for the 90mm M3 could come within 93%-95% of the performance of the longer German gun. Posters pointed out that this was "test" ammo, but the Zebra Mission Pershings seemed to have a decent supply of it. And I understand that by Korea the characteristics of the "special" AP shot was incorporated into standard rounds, and HVAP became readily available, so these rounds advanced beyond the experimental stage and Pershings became able to match the performance achieved late WW II on a normal basis. Any thoughts from the panel?

thehammer :)

#2 theHammer

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Posted 22 August 2009 - 1741 PM

If the 90mm M3 was capable of such performance with improved loads, what was the rational behind the longer barreled 90mm in the "Super Pershing"? Bigger gun, heavier, loading problems, etc...
Why not just concentrate on using the full potential of the existing weapon?

thehammer :)

#3 Przezdzieblo

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Posted 23 August 2009 - 0456 AM

I could expect that behind armor effect of APCBC-HE would be much greater than that of APBC. Deepth of penetration gives not much informations about result of firing to specific target.


Also see this topic --> http://208.84.116.22...showtopic=18562
post #6
90 mm M36 gun was pretty similar to M3 guns, but was developed form the start as tank gun, with increased chamber loading, using more if not full potential of 90 mm calibre. As could be seen in data published by bojan even then it was a bit inferior to long "88".

#4 theHammer

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Posted 25 August 2009 - 1850 PM

"As could be seen in data published by bojan even then it was a bit inferior to long "88". "

A bit inferior, but the improved ammo brought the capabilities of a 45 ton Pershing significantly closer to the top tank on the battlefield without needing a completely new gun to do it.

thehammer :)

#5 Przezdzieblo

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Posted 26 August 2009 - 0048 AM

What improved ammo?

And yes, "closer to the top", but does it mean "to the top"?

#6 theHammer

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Posted 30 August 2009 - 0056 AM

What improved ammo?

And yes, "closer to the top", but does it mean "to the top"?


The T33 and HVAP were improved ammo versus what had previously been available to the M36 TD crews.

Given that Pershing was lighter and more mobile than a King Tiger, and could be produced in vastly greater numbers, "closer to the top" was probably close enough, had the war gone on long enough for it to become an issue.

thehammer :)

#7 ickysdad

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Posted 30 August 2009 - 0125 AM

The T33 and HVAP were improved ammo versus what had previously been available to the M36 TD crews.

Given that Pershing was lighter and more mobile than a King Tiger, and could be produced in vastly greater numbers, "closer to the top" was probably close enough, had the war gone on long enough for it to become an issue.

thehammer :)


More mobile then just in speed and such ..Just imagine building landing craft for a King Tiger or a Bailey type bridge or just having to transport them in power projection role as the US had to do in WW2.

#8 theHammer

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Posted 30 August 2009 - 0234 AM

More mobile then just in speed and such ..Just imagine building landing craft for a King Tiger or a Bailey type bridge or just having to transport them in power projection role as the US had to do in WW2.


No doubt. How would you have to reinforce the floor of a cargo area to hold a King Tiger up? If you tried, you might get two or three Pershings in the space a KT would take up.

thehammer :)

#9 Marek Tucan

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Posted 30 August 2009 - 0240 AM

No doubt. How would you have to reinforce the floor of a cargo area to hold a King Tiger up? If you tried, you might get two or three Pershings in the space a KT would take up.

thehammer :)


And conversely didn't Pershing take up, as ship cargo, place where up to four Shermans can fit? Maybe only in landing crafts though, cannot recall correctly...

#10 alejandro_

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Posted 02 November 2010 - 1024 AM

US War department pamphlet with information on AP ammo for 90mm M3 gun, it contains many interesting photos and diagrams.

http://www.lonesentr...tion/index.html

#11 xenogears1978

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Posted 14 February 2011 - 0335 AM

Please remember that T33 has no charge but L71 APCBC do.It has much more strength.

Germans don't have an ammo quite corresponds to T33.If they make one,it will be much better than pzgr39.

also note that the only t33 test against panther glacis is a cheat,one hit on the edge and another one near it.We don't have a solid example or test to prove exactly how far T33 kills.

As for the russian ammo,all russian books I read admit 600-700 mpanther glacis for Br-471,and 1200-1400m for Br-471B,which is only available after 1945.

Not to mention the Wapruef report that considers panther glacis undefeatable by 122mm.

#12 bojan

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Posted 14 February 2011 - 0707 AM

If they make one,it will be much better than pzgr39.


APHE loses ~3-5% of penetration compared to pure AP. So not much.

also note that the only t33 test against panther glacis is a cheat,one hit on the edge and another one near it.

Cheat or not in real life tose hits would KO tank...

As for the russian ammo,all russian books I read admit 600-700 mpanther glacis for Br-471,and 1200-1400m for Br-471B,which is only available after 1945.

Which fits with US tests of BR-471B... And January 1945. should be exact date.

Not to mention the Wapruef report that considers panther glacis undefeatable by 122mm.

Because it was defeated IRL and there are pictures yo prove it.

#13 irregularmedic

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Posted 14 February 2011 - 1140 AM

APHE loses ~3-5% of penetration compared to pure AP. So not much.


Cheat or not in real life tose hits would KO tank...


Which fits with US tests of BR-471B... And January 1945. should be exact date.


Because it was defeated IRL and there are pictures yo prove it.


Wouldn't even an HE shell from a 122mm defeat the Panthers frontal armor? Aside from that likely destroying the machine I can't imagine a crew being very combat effective after getting suffering the concussive effects of that blast. Not to mention optics and machinegun barrels likely being gone or broken...

#14 xenogears1978

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Posted 16 February 2011 - 0113 AM

Wouldn't even an HE shell from a 122mm defeat the Panthers frontal armor? Aside from that likely destroying the machine I can't imagine a crew being very combat effective after getting suffering the concussive effects of that blast. Not to mention optics and machinegun barrels likely being gone or broken...



HE ko armor?Keep dreaming.
KV got hit by 105 and it still killed.
M26 got hit by 150 in the rear and the crew alive and running.

KO optics?maybe.

If HE can kill frontal armor,all the rules of tank engagement will be changed.

#15 xenogears1978

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Posted 16 February 2011 - 0115 AM

HE ko armor?Keep dreaming.
KV got hit by 105 and it still killed.
M26 got hit by 150 in the rear and the crew alive and running.

KO optics?maybe.

If HE can kill frontal armor,all the rules of tank engagement will be changed.


and bojan,be kind and tell us just how L71 do in the us test?and american test of BR-471B?

also what do you think of the russian claim of 2500 kill of panther front?

#16 xenogears1978

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Posted 16 February 2011 - 0337 AM

somehow i find the wapruef report put so much credit in slope to a strange level.

it put panther glacis invincible to 17pdr and 122mm.
put t-34 glacis 300m for panther and 100m for tiger.
put m4a2 glacis 100m for panther and null for tiger.

inexplicable

#17 Simon Tan

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Posted 16 February 2011 - 0525 AM

The quality of crunchies is depressingly poor these days. They live in a world of abstract numbers and absolutes. That and an appalling lack of grammar and diction.

#18 bojan

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Posted 16 February 2011 - 0545 AM

HE ko armor?Keep dreaming.


Check real world for facts. 152mm HE from SU/ISU-152 killed pretty much anything it connected with. Lot of KVs were killed by 150mm howitzers in 1941. with pretty much fenomenal effect.

KV got hit by 105 and it still killed.

105mm vs 122mm HE is world of difference.
And KV had more top and side armor then Panther (IRL most of tanks are killed by flanking fire).


M26 got hit by 150 in the rear and the crew alive and running.

Fuse set to superquick.

KO optics?maybe.

From a front hit? Optics COed, Turret jammed, thinner armor plates cracked, welds failing etc...

If HE can kill frontal armor,all the rules of tank engagement will be changed.

Not reliably, but it was used pretty often - eg. Soviet 76mm HE fired with delay fuse seriously damaged 30mm armor on German tanks in 1941 (one of the reasons shurtzen was introduced, other being 14.5mm ATRs).
Guess what will happen when 122mm HE hits Panther's side, which is not that much thicker...
Read US study on arty close hits vs modern armor. Tanks do not fare well vs large HE.

#19 bojan

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Posted 16 February 2011 - 0546 AM

The quality of crunchies is depressingly poor these days. They live in a world of abstract numbers and absolutes. That and an appalling lack of grammar and diction.


You can blame me, as I advertised Tanknet heavily on WoT forums...

#20 alejandro_

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Posted 16 February 2011 - 0552 AM

Wouldn't even an HE shell from a 122mm defeat the Panthers frontal armor?


When Tiger-II was tested in Kubinka it was subjected to hits by different guns. First hit in the front armour (150mm at 50) was a 122mm HE impact from 100 meters. The welding between the right and upper plate broke causing a 5mm gap. Welding around MG also broke.

The quality of crunchies is depressingly poor these days. They live in a world of abstract numbers and absolutes. That and an appalling lack of grammar and diction.


:lol: I think he is Japanese, so lets also understand that it is a rather different language to English :)




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