Updated tank gun comparison

[Soren]

For me the most important figures given above are sec. density and kinetic energy per cm^2. The latter does provide a rough indication of initial penetration performance (at the muzzle, everything else beeing equal), the former shows how well the projectile will keep it´s penetration performance at distance (actually APCBC will be better than APC due to the aerodynamic windscreen). Energy retention is heavily linked to sec. density and form factor.
projectile properties are not taken into account but it still gives a reasonable idea about the gun itselfe.

Yeah, but we're actually up in a weight class where the retainment of velocity is very close for all the projectiles. The difference in the loss of velocity between for example the 7.5cm APCBC projectile and the 12.8cm APCBC projectile at 2km isn't much.

 

[vikingBerserker]

I bet the rabbits could not hear squat after that hit.

 

[hartmann]

I also still don´t understand the post of MrKenny.

What sense has to compare an 12,8 cm PzGr rot APC made in 1944 or 1945, with a top level armour plate made in 1949 (which, also to clarify, was a modified recipe of the German Wh n/A, which the Great Britain tank armour designers happily adopted after the war as It outperformed all their own armour steel?).

It would be as worthless as a trial series made by Yugoslavian army in 1961 with their brand new T-54 tanks and a series of AT guns, including an old gun PaK43 firing APCBC PzGR39/43 shells and a heavily modified hybrid PzGr 40/43 with tungsten core from 90 mm M3 gun shell.
The gun was captured to Germany in late 1944 (barrell highly eroded).
In the trials, It was not capable (alegedly by the yugoslavians) to penetrate the 100 mm glacis at 60º even at point blank range. But it didn´t specified if dented the armour, if It ricochetted, if It ejected plugs of steel or whatever happened to the 88 mm shell. Never was mentioned MV nor ballistic limit velocity needed.
Curiously, It was said that cut the 203 mm of casted steel of the front of the turret easily with the PzGr39/43.

Best regards.

 

[m kenny]

I also still don´t understand the post of MrKenny.

I'm not sure what it is m_kenny is trying to prove

Curious reactions.
I saw this:

At that point, the penetration of the round[12.8cm] is impressive but so is the explosive effect. One of those things go off against the side of a tank will probably disable if not destroy it.

and knew I had the details about a point-blank firing of this gun at an uparmoured Churchill so I posted it.
It seems to escaped many that this Churchill had 9.5 INCHES of armour.

I'd like to know where m_kenny's picture is from though

Page 196 of Mr Churchill's Tank'
Mr. Churchill's Tank: The British Infantry Tank Mark IV: David Fletcher: Amazon.co.uk: Books

"The tank was uparmoured to a maximum 235mm with
patches of applique armour welded to the sides of both turret
and hull. and then fired at with armour piercing capped rounds
of 128mm from the ridiculously short range of 100 yards. The
gun in question was either the PaK44 1/55 as fitted to the
huge German Jagdtiger (SdKfz 186) self propelled gun or
the KwK44 L/55 of the superheavy tank Porsche Type 205
Maus. The actual gun is not specified but it is interesting to
speculate upon whether, if it was the PaK 44, an actual
Jagdtiger was used or if the gun was mounted on a range
mounting. If it was the KwK44 then it would have to be on a
range mount.
Three rounds were fired; two at the hull sides, one at the
turret. Those which struck the hull gouged great chunks out
of the applique armour and cracked many welds but did not
penetrate. The one that struck the turret virtually tore it off.
The applique plate was smashed to pieces and the turret side
bulged inwards but again there was no actual penetration.
Even so many internal fittings were torn loose and all the
hatches were ripped off the turret, including the entire com-
manders cupola. There seems little doubt that any tank, hit
this hard, would be totally disabled by the blows. To discover
how the crew might have fared two rabbits were placed in-
side the tank, each in its own little wire cage, but they sur-
vived all three rounds and, according to the report, appeared
to be unaffected."

and how he can be sure that the description is right.

David Fletcher (the author) was the Librarian and then Curator of Bovington Tank Museum and thus had unrestricted access the the documentation. I admit I rely on his account but you would have to be very sure of your ground to challenge his word.

I mean seeing that a round supposedly knocked the turret off I'd atleast expect to see a freaking dent! I'd actually like to see some evidence of hits on the tank at all.

From the angle of the turret and the way it went to the right one must assume the hit is on the right side of the turret-the bit facing away from the camera. APC rounds are mentioned
I presume the '2' we see below on the dented and bent side applique armour marks the 2nd hull hit.

 

[Soren]

m_kenny our reaction wasn't at all curious as Tim was talking about a high explosive round.

Now as for the picture, well unless the gun wasn't firing the std. German rounds for some odd reason or some new type of armour was used on the Churchill, then the PaK44 should've punched straight through that armour at 100 yards. At 100 yards it did afterall achieve an average penetration performance of 267mm of 240 BHN RHA armour at the Aberdeen Proving Grounds USA. So unless the Churchill in question used some new type armour or the gun fired a British made APC round, then the description really has no credibility.

Oh and you can be quite sure that the mark below the letter '2' on the tank isn't a dent made by a 12.8cm round, if so it would've been appreciably larger! Note the diameter of the supposed dent vs the diameter of the puny 6 pdr, it's actually smaller than the 6 pdr!

 

[m kenny]

Now as for the picture, well unless the gun wasn't firing the std. German rounds for some odd reason or some new type of armour was used on the Churchill, then the PaK44 should've punched straight through that armour at 100 yards. At 100 yards it did afterall achieve an average penetration performance of 267mm of 240 BHN RHA armour at the Aberdeen Proving Grounds USA. So unless the Churchill in question used some new type armour or the gun fired a British made APC round, then the description really has no credibility.

Unfortunately I do not consider this to be enough to doubt Fletcher's account..

Oh and you can be quite sure that the mark below the letter '2' on the tank isn't a dent made by a 12.8cm round, if so it would've been appreciably larger! Note the diameter of the supposed dent vs the diameter of the puny 6 pdr, it's actually smaller than the 6 pdr!

So it it was a 6pdr (or smaller) that smashed the welded applique plates, displaced the turret, cracked welds, blew the hatches off and wrote off a tank with 9.5 inches of armour with three 'puny' shots?
One can be sure the account is accurate and until such time as evidence of duplicity or deception surfaces that really is the end of it.

 

[Soren]

I really don't care what you consider enough m_kenny, I know you only posted that picture to start an argument.

But I can tell you that with the PzGr.43 the 12.8cm PaK44 would've had no problem punching through 267mm of high quality RHA armour at 100 yards, and that's fact. So it wasn't a PzGr.43 which was fired against the Churchill atleast.

 

[delcyros]

Please don´t cut hairs.

Armour penetration is not a precise function. What we don´t know is actually:

A) impact velocity.
-well, we know the distance but we really don´t know how much barrel wear the Pak 44 had in 1949. 100 EFC rounds fired may have a drastic effect on muzzle velocity and correspondingly on impact velocity at 100 yards.

B) actualy impact obliquity.

C) metal properties of armour (what armour was used, was it ever tested?)

D) type of ammunition used.

E) was the Churchill target for other firing trials?

Further, 9.5 in IS REALLY A DEEP THICKNESS! That´s 1.84 cal thickness for the 12.8cm, a very tough obstacle for any gun firing APCBC. All sorts of things could go wrong with this thickness relation on a projectile.

Factoring in the uncertainities outlined above, I don´t consider that the firing tests at Aberdeen and against the uparmoured Churchill are not in such a striking disagreement.
Thanks for posting this case, m_Kenny.

That beeing said, I also find it difficult to see the small gauge at Nr. 2 beeing identified with a 12.8cm round. The diameter is to small (well, it could be a 12.8cm HE round going up low order after penetrating a very short distance). But more importantly, the picture does not fit the textual description. It evidently did not gauge out great chunks of the apllique armour, smashed armour pieces and cracked many welds. The plate is in a fine condition.

 

[Juha]

hello Delcyros, IMHO the Churchill had its appliqué armour removed from its left side, turret had its right side appliqué still in place. The shallow gouge is the mark which the shell had left to original armour under/behind the appliqué.

BTW the gun of Churchill seems to be 75mm not 6pdr.

Juha

 

[hartmann]

Hello Delcyros ¡¡ Nice to see you again ¡¡

C) metal properties of armour (what armour was used, was it ever tested?)

If It was the standard armour used post-war (even in 2003 trial firings, The British ministry of armament used the Wotan hart n/A slightly modified), It should be a variant of the German Wotan Hart n/A, with British hardness and mechaic-thermical standards.

D) type of ammunition used.

As Soren said, It is strange the effect. It may habe been the very primitive APC variant (PzGr or PzGr rot). The standard ammo after inital trials of the gun was the PzGr 43 (new designation for the scaled-up to 128 mm PzGr 39/43 of the PaK43 88 mm, that is, an APCBC-HE ultra hardened blunted cap shell with variable progressive decremental hardness in the body of the shell).

Also, this gun could be fired with three MVs:
845-860 m/s (reduced charge), some 940 m/s (medium charge) and some 1000 m/s (full special charge) if my memory doesn´t fail, using different charges to avoid excesive erosive effects on the gun.

Further, 9.5 in IS REALLY A DEEP THICKNESS! That´s 1.84 cal thickness for the 12.8cm, a very tough obstacle for any gun firing APCBC. All sorts of things could go wrong with this thickness relation on a projectile.

As Yugoslavians said, the 88L71 with PzGr39/43, was capable of penetrate the 203 mm of cast steel armour of the front of the turret of the T-54 until some 500 metres (what I dont understand is the alleged inability to do so at the glacis of 100 mm at 60º even at point blank range, but they didn´t specified MV nor barrell erosion).

Best regards to all

 

[Soren]

All there really is left to say about the picture is that it definitely wasn't an APC or APCBC round fired at that Churchill, that's for sure. The tank was probably fired upon with HE rounds.

For those in doubt the just look at the Aberdeen results or those achieved by the Soviets.

 

[m kenny]

The tank was probably fired upon with HE rounds.

There is usualy a large splash ring around the impact area of a HE 'direct hit' on armour plate.

 

[Soren]

Yes, when the first piece of armour is hit it looks like that, but like Juha said the extra added side armour plate hit isn't there, and the small dent is therefore the result of the first armour plate taking the brunt of the impact.

And again a 128mm AP projectile does not leave a mark anything like that on the picture, no solid AP projectile would. AP projectiles carve into armour, they don't dent it.