# Updated tank gun comparison



## Soren (Jun 20, 2009)

Here's an updated WW2 tank gun comparison.

I've looked through US German manuals, modern day data and so on to make sure everything is 100% accurate.

*12.8cm PaK44 L/55*

Projectile weight: 28.3 kg (PzGr.43 APCBC)
Sectional Density: 1.727
Muzzle Velocity: 880 m/s
Total Kinetic Energy: 10957 KJ
Kinetic Energy pr. cm^2: 85.15 KJ

*8.8cm KwK43 L/71*

Projectile weight: 10.4 kg (PzGr.39/43 APCBC)
Sectional Density: 1.342
Muzzle Velocity: 1000 m/s
Total Kinetic Energy: 5200 KJ
Kinetic Energy pr. cm^2: 85.49 KJ

*10cm D-10*

Projectile weight: 15.88 kg (BR-412D APBC)
Sectional Denisty: 1.588
Muzzle velocity: 887 m/s
Total Kinetic Energy: 6246 KJ
Kinetic Energy pr. cm^2: 79.52 KJ

*7.5cm KwK42 L/70*

Projectile weight: 7.2 kg (PzGr.39/42 APCBC)
Sectional Density: 1.280
Muzzle Velocity: 925 m/s
Total Kinetic Energy: 3080 KJ 
Kinetic Energy pr. cm^2: 69.7 KJ 

*7.62cm 17pdr *

Projectile weight: 7.7 kg (Solid shot AP)
Sectional Density: 1.326
Muzzle Velocity: 883 m/s
Total Kinetic Energy: 3001 KJ
Kinetic Energy pr. cm^2: 65.8 KJ

*12.2cm D-25T L/43*

Projectile weight: 25 kg (BR-471B APC)
Sectional Density: 1.679
Muzzle Velocity: 780 m/s
Total Kinetic Energy: 7605 KJ
Kinetic Energy pr. cm^2: 65 KJ

*9.0cm M3 L/53*

Projectile Weight: 10.94 kg (M82 APBC) 
Sectional Density: 1.350
Muzzle Velocity: 853 m/s
Total Kinetic Energy: 3980 KJ 
Kinetic Energy pr. cm^2: 62.56 KJ

*8.8cm KwK36 L/56*

Projectile weight: 10.2 kg (PzGr.39-1 APCBC)
Sectional Density: 1.317
Muzzle Velocity: 773 m/s
Total Kinetic Energy: 3107 KJ
Kinetic Energy pr. cm^2: 51.09 KJ

*8.5cm D-5T L/54*

Projectile weight: 9.2 kg (BR-365 APBC) 
Sectional Density: 1.273
Muzzle Velocity: 792 m/s
Total Kinetic Energy: 2885 KJ
Kinetic Energy pr. cm^2: 50.84 KJ

*7.6cm M1 L/55*

Projectile weight: 7.0 kg (M62 APCBC) 
Sectional Density: 1.211
Muzzle Velocity: 792 m/s
Total Kinetic Energy: 2195 KJ
Kinetic Energy pr. cm^2: 48.38 KJ

*7.5cm KwK40 L/48*

Projectile weight: 6.8 kg (PzGr.39 APCBC)
Sectional Density: 1.208
Muzzle Velocity: 790 m/s
Total Kinetic Energy: 2122 KJ
Kinetic Energy pr. cm^2: 48.03 KJ


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## fastmongrel (Jun 20, 2009)

Hi Soren thanks for that info very interesting comparison but could you tell me what the sectional density means I think I understand all the other figures but that has got me stumped.

I also noted that the 76.2 mm 17 pounder and the 7.5cm KwK42 are remarkably similar in all figures obviously the German and British designers were thinking along the same lines.


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## Soren (Jun 20, 2009)

Sectional density in very rough terms pretty much refers to the projectile's ability to penetrate a certain object at a certain speed. The higher the SD the higher the penetrative ability pr. amount of speed.


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## hartmann (Jun 20, 2009)

Hello Soren. 

Thanks a lot for the data on sectional density and KE/cm2. It is an excellent work ¡¡

Does the sectional density correlates with capability to remain intact upon penetration?

Thanks a lot and my best regards


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## vikingBerserker (Jun 20, 2009)

Nice data Soren!


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## Matt308 (Jun 21, 2009)

Soren said:


> Sectional density in very rough terms pretty much refers to the projectile's ability to penetrate a certain object at a certain speed. The higher the SD the higher the penetrative ability pr. amount of speed.



While Soren is correct, this is somewhat of an arbitrary number used for calculation of ballistic coefficient and gross ascertion of performance. This number in an of itself is not conclusive to the efficiency of a particular round's ability to travel farther, with less drift or ability to penetrate an objective media. I am unfamiliar with the use and validity of this parameter applied to ballistics beyond small arms.


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## Soren (Jun 21, 2009)

You're completely right Matt, there are MANY other factors which affect the penetrative ability of a AP projectile, and one of the most important is the steel quality and composition. 

Much more important to penetration performance is the pressure/energy pr. surface area generated, which is shown as the KE pr. cm^2.


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## Soren (Jun 23, 2009)

Btw guys, you're welcome to provide similar data on other guns if you wish. In the end we might get a sticky made out of it


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## timshatz (Jun 23, 2009)

Impressive post Soren. 

Any numbers on armor penetration? I realize it would be tricky, differing plates and all that, but it would be interesting. 

Was impressed by the kinetic energy by the 12.8cm round. That sucker hits with some impact. Even makes the 88 look relatively docile.


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## lesofprimus (Jun 23, 2009)

Agree with u Tim in a big way.... 10957 KJ tops the list....

Thanks for the info Soren....


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## Soren (Jun 23, 2009)

Thank you guys, you're most welcome.

Tim,

I could add penetration stats but like you rightly pointed out it would get abit confusing seeing that every country tested their guns against different quality and different BHN plates. So instead I decided to add the energy spread pr. surface area, which looks past steel quality, form factor, test critierias etc etc and just provides you with the raw penetration power that the gun offers. As you can see the 8.8cm KwK43 tops the list, barely superceding the 12.8cm PaK44, but I must point out that after just 1,000 m it has reversed and the PaK44 is slightly ahead. By 2,000 m the difference in the penetration performance established in German tests between the 12.8cm PaK44 and 8.8cm KwK was a mere 16 mm (132mm vs 148mm) in favor of the PaK44, so they were close.

You also see why the Soviets should have opted for the 10cm D-10 instead of the 12.2cm D-25T, the D-10 was an extrememly powerful gun with a lot of potential. With an identic projectile it was only slightly behind the 8.8cm KwK43 in penetration performance at all ranges, but the larger HE shell would've made up for that.


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## timshatz (Jun 24, 2009)

I was kicking it around in my head last night and realized the 12.8cm gun was the same size but longer than the US Navy's 5" 38 that was used on US destoyers as a primary weapon during the war. Round weights about the same. 50Lb or so. 

At that point, the penetration of the round 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. 

Honkin' big round.


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## Stitch (Jun 24, 2009)

timshatz said:


> I was kicking it around in my head last night and realized the 12.8cm gun was the same size but longer than the US Navy's 5" 38 that was used on US destoyers as a primary weapon during the war. Round weights about the same. 50Lb or so.
> 
> At that point, the penetration of the round 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.
> 
> Honkin' big round.



No kidding!

It's also interesting to realize that the MBT's of today don't even have guns this big (though their MV is much higher), so the PaK44 wouldn't be too out of place even today.


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## m kenny (Jun 24, 2009)

In 1949 a Churchill with 235mm of applique armour was fired at from 100yds by a German 128mmm gun.
2 AP hits on the hull left gouges and cracks but did not penetrate. One hit on the turret knocked it off but did not penetrate. 2 rabbits placed in cages inside the tank survived and showed no ill effects!


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## plan_D (Jun 24, 2009)

Nice list there, Soren. Good to see all information collected and easily referenced. 

m_kenny, the Churchill was a bit of a beast when it came to absorbing rounds, eh? Unfortunately if your turrets come off, your battle is pretty much over.


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## delcyros (Jun 24, 2009)

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.


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## DerAdlerIstGelandet (Jun 24, 2009)

m kenny said:


> In 1949 a Churchill with 235mm of applique armour was fired at from 100yds by a German 128mmm gun.
> 2 AP hits on the hull left gouges and cracks but did not penetrate. One hit on the turret knocked it off but did not penetrate. 2 rabbits placed in cages inside the tank survived and showed no ill effects!



Who cares, it was still knocked out of action...

Nice picture though.


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## plan_D (Jun 24, 2009)

I agree, the picture's cool. But I have to also mention...rabbits...the physical make-up of a rabbit is ...well, a lot different from that of a human. Given the size of a human in such a confined space, I'm thinking physical damage would have been more likely especially if the freakin' turret fell off.


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## DerAdlerIstGelandet (Jun 24, 2009)

plan_D said:


> I agree, the picture's cool. But I have to also mention...rabbits...the physical make-up of a rabbit is ...well, a lot different from that of a human. Given the size of a human in such a confined space, I'm thinking physical damage would have been more likely especially if the freakin' turret fell off.



I agree...


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## Soren (Jun 24, 2009)

I'm not sure what it is m_kenny is trying to prove cause I've got the Aberdeen results for the 12.8cm PaK44 and it easily outperformed any other gun tested in terms of penetration performance, only the 8.8cm KwK43 came close. At Aberdeen the PaK44 punched through 267mm of vertical 240 BHN RHA armour at 100 yards with the regular APC round, the KwK43 managed 232mm with the regular APCBC round and a phenomenal 304mm with the APCR round!

I'd like to know where m_kenny's picture is from though and how he can be sure that the description is right. 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.


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## Soren (Jun 24, 2009)

delcyros said:


> 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.


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## vikingBerserker (Jun 24, 2009)

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


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## hartmann (Jun 24, 2009)

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.


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## m kenny (Jun 24, 2009)

hartmann said:


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





Soren said:


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



Curious reactions.
I saw this:



timshatz said:


> 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.




Soren said:


> 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._"




Soren said:


> 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.




Soren said:


> 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.


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## Soren (Jun 24, 2009)

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!


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## m kenny (Jun 24, 2009)

Soren said:


> 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..



Soren said:


> 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.


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## Soren (Jun 24, 2009)

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.


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## delcyros (Jun 25, 2009)

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.


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## Juha (Jun 25, 2009)

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


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## hartmann (Jun 25, 2009)

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


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## Soren (Nov 16, 2009)

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.


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## m kenny (Nov 16, 2009)

Soren said:


> 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.


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## Soren (Nov 16, 2009)

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.


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