WWII Tank Gun Specifications

[Soren]

A slightly better ballistic performance doesn't explain the fact that the Panther starts out at 168mm and ends up at 91mm, while the 17 pdr starts out at 163mm and ends up at 107mm, since if the L/70 has better high target angle performance this should offset the increase in target angle at long range which occurs as a natural result of the projectile trajectory.

It may surprise you to know how flat the trajectory of a 800+ m/s cannon actually is. We're not talking howizter trajectories here.

Also take a look at the 8.8cm PzGr.39-1's performance, it goes from 151mm to 97mm, that's better than both.

 

[Vincenzo]

Hi Vincenzo

The 90 mm gun fired a 22.2 lb AP round at a muzzle velocity of 2,756'/sec.6 It's maximum range was 15,000 yards.6 It could penetrate 5.63"@0° at 500 yards.

I t makes for an interesting comparison with the German 88mm series

thank you. This is a british test? afaik italian standard AT round had HE fillers so were AP(HE) or APBC(HE)

p.s. unlucky italian 90mm carriage was more large and high of that of 88 so the use as ATG of this AAG was not so easy. (almost this is the common explanation, i not checked but maybe also the italian gun it's longest (the misuration it's not same in italian army and in german army)

 

[parsifal]

The source says that it was from data obtained at Aberdeen in 1968. I dont know any more than that

 

[dunmunro1]

Here's data from the same source for the 17 pdr APDS:
500m = 256mm
1,000m = 233
1,500m = 213
2,000m = 194
2,500m = 178
3,000m = 162

Perhaps Soren could post the data for the 6 pdr APDS?

 

[Juha]

Hello
"Fire and Movement", RAC Tank Museum, Bovington, 1975, pages 22–25. "Penetration v. homogenous armour at 30º, at ranges in yards". The armour is machineable quality.

6-pdr Mk 3 or 5 APDS 131mm@500, 117mm@1000, 103mm@ 1500, 90mm@ 2000

Juha

 

[Soren]

Here's data from the same source for the 17 pdr APDS:
500m = 256mm
1,000m = 233
1,500m = 213
2,000m = 194
2,500m = 178
3,000m = 162

Perhaps Soren could post the data for the 6 pdr APDS?

Sure can, but like I've said before APDS was a poor ammunition type during WW2, it was inaccurate and poor against sloped armour, had poor killing power once penetration was achieved and in short supply. So I really do not understand why you're so obsessed with this projectile type. APCBC rounds were the most lethal AP projectiles used during WW2, and were prefered for that very reason, Firefly gunners prefering the APCBC over the APDS round.

5.7cm 6pdr L/52 gun with APDS:
500m = 160mm
1,000m = 140mm
1,500m = 123mm
2,000m = 108mm
2,500m = 95mm
3,000m = 83mm

 

[dunmunro1]

6 pdr APDS 4000fps
0 targe angle MQ armour
500yds=173mm
1000yds = 153
2000yds = 119

http://www.wwiiequipment.com/index....er-anti-tank-gun&catid=40:anti-tank&Itemid=58

 

[Soren]

Fits well with the US test results once adjusted into meter results.

 

[dunmunro1]

Sure can, but like I've said before APDS was a poor ammunition type during WW2, it was inaccurate and poor against sloped armour, had poor killing power once penetration was achieved and in short supply. So I really do not understand why you're so obsessed with this projectile type. APCBC rounds were the most lethal AP projectiles used during WW2, and were prefered for that very reason, Firefly gunners prefering the APCBC over the APDS round.

You've certainly said this and been corrected for saying it, but 6 pdr APDS was not inaccurate and had none of the problems that 17 pdr ammo had. 6 pdr APDS was more accurate than APCBC, and it was available from day one of the Normandy Campaign.

 

[Soren]

You've certainly said this and been corrected for saying it, but 6 pdr APDS was not inaccurate and had none of the problems that 17 pdr ammo had. 6 pdr APDS was more accurate than APCBC, and it was available from day one of the Normandy Campaign.

You're making one untrue claim after the other. 6 pdr APDS ammunition was not at all more accurate than APCBC, the APDS rounds of the time all suffered from the same problems, and again they were in short supply. And where exactly have I ben corrected on this issue? So far I've only seen you being corrected after making claims again and again and again.

 

[dunmunro1]

You're making one untrue claim after the other. 6 pdr APDS ammunition was not at all more accurate than APCBC, the APDS rounds of the time all suffered from the same problems, and again they were in short supply. And where exactly have I ben corrected on this issue? So far I've only seen you being corrected after making claims again and again and again.

http://www.ww2aircraft.net/forum/ww2-general/best-tank-ww2-20189-9.html#post615840
Accuracy:

First round accuracy was better for APDS. 6 pdr had none of the consistency problems that hampered the 17 pdr APDS. However, since APDS did not have tracer it was harder for the gunner to improve his aim on subsequent shots.

 

[Soren]

Those are estimated chances, hence the good performance of the 17 pdr APDS round on that sheet. In reality the APDS rounds proved poorin terms of accuracy, as demonstrated in actual tests.

 

[dunmunro1]

Those are estimated chances, hence the good performance of the 17 pdr APDS round on that sheet. In reality the APDS rounds proved poorin terms of accuracy, as demonstrated in actual tests.

LOL, show some tests were the 6 pdr APDS did poorly.

 

[Soren]

LOL, show some tests were the 6 pdr APDS did poorly.

I can show you tests where the 17 pdr APDS did A LOT worse than on that sheet. So why would the 6 pdr be any different? Was the APDS design for the 6 pdr different? Did it somehow by a miracle avoid the issues which plagued the 17 pdr's APDS rounds?

Sorry I dont buy it.

 

[dunmunro1]

There were some major differences between the 6 pdr and 17 pdr that had a large impact on APDS accuracy:

As I and others have pointed out, the 6 pdr APDS did not suffer from accuracy problems, except those caused by the extreme MV and lack of tracer. 17 pdr APDS ammo needed to be manufactured to much higher standards than APCBC and 17 pdrs firing APDS needed to keep their barrels very clean as the aluminium from the sabot fouled them rapidly.

Regarding 6 pdr APDS:

"...Indeed. the 6 pdr AT gun, either towed or carried in the Churchill, was preferred for AT actions, especially when equipped with the new APDS ammo, which greatly enhanced AP capabilities. Montgomery commented on the popularity of the 6 pdr with sabot ammo in his memo no 506 of 6 July (1944) whilst simultaneously criticising the (Allied) 75mm gun..."p130.
British armour in the Normandy campaign, 1944
By John D. Buckley

The 6 pdr with APDS was a fearsome weapon with few drawbacks over the same gun with APCBC ammo. 17 Pdr APDS was not inherently inaccurate but demanded better manufacturing standards and it was harder to keep a 17 pdr firing accurately with APDS with increased fouling and gun wear. Theoretically 17 pdr APDS was more accurate than APCBC, but in practise this was not always the case.

In any event, I'm interested in the data Soren is presenting, but I have some reservations about its accuracy and applicability to actual combat, while APDS ammo was used widely and successfully by 21st AG, much to the discomfort of German armour. At 500 meters, 17 pdr APDS is number one in penetration according to Soren's own data, while the 6 pdr is only slightly behind the 75mm L/70.

 

[Soren]

That's all fine and dandy but are there actual tests available to confirm the theory? Fact is that the 17 pdr performed far worse with APDS ammunition than the sheet estimates, and so pure logic tells us that the 6 pdr would suffer from the same issues. You have now provided documentation for why the 6 pdr probably didn't suffer from the same issues with accuracy, but we have no real tests to confirm it, as we have with the 17 pdr which proved to have poor accuracy with APDS ammunition.

If you can find real tests that conclude good accuracy with a large sample of 6 pdr APDS ammunition as the Germans did with all their ammunition types, then you will have convinced me that the 6 pdr was accurate with APDS ammunition.

Even so APDS ammunition still suffered from problems with lack of destructive power after penetration, shattering and low availability. All countries had sub caliber ammunition which could penetrate a lot of armour, but due to shortages in tungsten it never became available in huge numbers, and due to its lack of destrutive power after penetration it was generally turned down in favour of APCBC ammunition which also worked better against highly sloped armour.

 

[Juha]

On availability of 6pdr Sabot, production, in 1944 217.000, in 1945 158.000.

Penetration ability against sloped plate, in this case 17pdr against the 80mm thick glacis plate of a Panther:
(6) In contrast to the results obtained in this teast with 17pdr SABOT, in firing conducted by First U.S. Army at Balleroy on 10 July 44, 5 rounds were fired at the front plate of a Panther tank at 700 yards. Examination of pictures of this firing indicates that the first round struck the mantlet, the second between the track and the nose plate, the third at the junction of the nose and glacis and penetrated. The fourth and fifth were fair hits on the glacis and both penetrated…

Juha

 

[Soren]

From the same paper:
"6. Conclusions
a. That the 17pdr SABOT of the lot tested is considered an unsatisfactory ammunition because of its inaccuracy.

b. That the 76mm APC, M62 is considered an unsatisfactory ammunition for use against heavy armor because of its inferior penetration.

c. That the 17pdr APCBC and the 76mm HVAP, T4 are considered the best antitank ammunitions available in these calibers for use against heavy armor. The 17pdr APCBC is somewhat superior to the 76mm HVAP, T4, against the Panther Tank. Neither one can be be depended upon to penetrate the glacis plate of the Panther in one fair hit on average quality plate."

 

[dunmunro1]

That's all fine and dandy but are there actual tests available to confirm the theory? Fact is that the 17 pdr performed far worse with APDS ammunition than the sheet estimates, and so pure logic tells us that the 6 pdr would suffer from the same issues. You have now provided documentation for why the 6 pdr probably didn't suffer from the same issues with accuracy, but we have no real tests to confirm it, as we have with the 17 pdr which proved to have poor accuracy with APDS ammunition.

If you can find real tests that conclude good accuracy with a large sample of 6 pdr APDS ammunition as the Germans did with all their ammunition types, then you will have convinced me that the 6 pdr was accurate with APDS ammunition.

Even so APDS ammunition still suffered from problems with lack of destructive power after penetration, shattering and low availability. All countries had sub caliber ammunition which could penetrate a lot of armour, but due to shortages in tungsten it never became available in huge numbers, and due to its lack of destrutive power after penetration it was generally turned down in favour of APCBC ammunition which also worked better against highly sloped armour.

I think it is incumbent upon you to find data to prove your claim that 6 pdr ammo was inaccurate. I and others have pointed out that 6pdr APDS did not have accuracy problems. I have provided data showing you why this is case and I have showed you the differences between the guns that allowed the 6 pdr to fire APDS with no loss in accuracy.

APDS was more destructive than APCBC because it was more likely to penetrate! When it did penetrate at equal ranges to APCBC it had more residual SV and caused more damage inside the tank. APDS was not in sort supply, relative to specialized tungsten core shot. APDS performed as well as any round when striking highly oblique targets.

 

[Juha]

Hello Soren
and the explanation why 17pdr Sabot didn't work well at U.S. Army Firing Tests conducted August 1944 by 12th U.S. Army Group at Isigny, France, from the same paper, straight after my earlier quote.

"The conflict between these results and those obtained by the board is explained by Col. A. G. Cole, Deputy Director of Artillery, Ministry of Supply. Col. Cole witnessed part of the test and states that the ammunition lot furnished the board had not been proof fired. He further states that, in his opinion, the lot is of sub-standard manufacture and if proof fired would not have been accepted."

So 17pdr Sabot used in Isigny was most probably sub-standard, so it's rather useless to draw too much from it on the behaviour of 17pdr Sabot.

Juha