Early HEAT Ammunition

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Stovepipe
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Re: Early HEAT Ammunition

#16

Post by Stovepipe » 26 Oct 2016, 02:03

I read somewhere that 400m was the maximum recommended for the L24 gun, to have a hope of a kill against a T-34 and that the best procedure was to fire four or five rounds to guarantee a total loss.

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Re: Early HEAT Ammunition

#17

Post by Paul Lakowski » 26 Oct 2016, 04:02

early heat rounds used cast iron /steel and not copper....while they took a number of hits to finish a target , that was true for most projectile plate actions.PAK 38 took 5-6 hits to destroyed tanks.


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Re: Early HEAT Ammunition

#18

Post by Yoozername » 26 Oct 2016, 05:36

A German report....
the following assessment of the effectiveness of the 7,5 cm Panzerjägerkanone 97/38
is a translation from a book called 'Die deutsche Panzerjägertruppe 1935 - 1945' written by
Wolfgang Fleischer and Richard Eiermann and published in 1998.


As one of the first of these makeshift solutions the 7,5 cm Panzerjägerkanone 97/38
reached the frontlines in early summer 1942. ... In the beginning mostly captured french and
polish ammunition was used but soon replaced, with the exception of HE-munitions, by
HEAT-rounds of german fabrication. These were able to penetrate 70mm of armor-plate (7,5 cm Granatpatrone
15/38 HL/A(f)) irrespective of target distance. The ultimately delivered 7,5 cm Granatpatrone
97/38 HL/C(f) could penetrate 100 mm. For the 7,5 cm Granatpatrone Panzer (p) a penetration
power of 58 mm armor-plate at 500 m distance and of 45mm at 2000 m are given.
In the authum of 1942 about 1600 guns of this type were available. Finally a small number of
150 pieces of the 7,5 cm Panzerjägerkanone 97/40 was produced. Only difference: the gun-carriage
was that of the 7,5 cm PAK 40.
Both modells were used in platoons of two guns each with the companies of antitank bataillons
(Panzerjägerabteilung).
At first they were classified as heavy later as medium antitank guns.
On 26 February 1943 'Schnelle Abteilung 290' reported their combat experiences with the
'schwere Panzerabwehrkanone 7,5 cm (f)':
"At distances between 200 - 800 m T-34 tanks could be engaged with good results."
As further advantages of the gun its effectiveness against infantry attacks, its low height and
easy training in every direction was pointed out.
The lack of tracer proved to be a disadvantage and caused a high expediture of ammunition.
A report by Heeresgruppe Nord claimed as many as 12 to 24 rounds necessary for each tank kill.
This was aggravated by the fact that the gun had no semiautomatic breechmechanism which
already slowed its rate of fire.
Another disadvantage was the 'jumping' of the gun when fired. This caused the gunner to
lose sight of his target after each shot. Moreover the manual firing mechanism tended to
fail quite often.
With the increase in production of the 7,5 cm PAK 40 the remaining guns were handed over
from the Panzerjägerabteilungen to the regimental antitank companies
[14.(Infanterie-Panzerjäger-)Kompanie]
of the infantry divisions. In 1945 they still could be found few in number in some fortress-antitank
units
(Festungs-Pak-Verbände).

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Re: Early HEAT Ammunition

#19

Post by Yoozername » 26 Oct 2016, 05:52

Christian Ankerstjerne wrote:
Yoozername wrote:I don't believe many nations could afford to use copper liners btw. Many use brass or aluminum or even soft steel.
Copper is not that expensive.

While most German HEAT ammunition, at least according to D 460/10, seems to have used steel (St VII 23), the price was hardly a factor. The 10 cm Gr. 39 HL/A used a 190 gram steel cone, which if replaced by the same volume of copper would weigh about 220 grams.

In 1943, one ton of copper cost 265 US Dollars, or about 530 Reichmarks. The cone of the 10 cm Gr. 39 HL/A would therefore cost about 12 Reichpfennigs. Assuming the same amount of copper had been used on the 75 mm HEAT ammunition as on the 105 mm HEAT ammunition, the copper used for the total wartime production of 7,5 cm Pak/Kw K/Stu K 40 and 7,5 cm Pak 97/38 HEAT ammunition (about 5.8 million rounds accepted by Waffenamt) would have cost about 700 000 Reichmarks more. By comparison, the Waffemamt ammunition production for the fourth quarter of 1942 alone was for 46.7 million Reichmarks.

A better argument is the raw material availability. Using the same example as above, the amount of copper needed would have been about 1276 tons for the full wartime production. This figure is much more significant compared to the total average monthly copper consumption of all Waffenamt branches of 2244.8 tons for the fourth quarter of 1942, of which 594 tons was used for ammunition.
Germany had a copper shortage even before the hostilities started. And, no, I was not referring to the price.

Most nations adopted measures such as soft iron shell cases. Brass could not be made in the volumes needed for the war.

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Re: Early HEAT Ammunition

#20

Post by Mobius » 26 Oct 2016, 14:33

Christian Ankerstjerne wrote:
Mobius wrote:You are right that the 75mm/L24 AP shell is more stable. An average of two sources gives it a 50% dispersion at 1000m of 0.55m. (now that I think of it could be an average of 0.5/0.6) The HL X/Y 50% dispersion is ~ 0.7m/0.84m (from working backwards from the German accuracy score). Still HEAT has a better chance to hit under 2000 meters if using range estimation in the accuracy calculation.
Thanks for those numbers.
I'm not really confident on those numbers as they were a result of trying to determine the dispersion from the German 'Training' accuracy numbers. And it may only be close for the 75mm/L24 HL HEAT shell and not apply at all to the HL/A, B or C shell. It is indeed strange that the 'Training' percent for the HL is 61% at 1500m for the 75mm/L24, when at the same time the HL/C 'Training' accuracy of the 75mm/L48 at 1500m is 42%. They have almost the same muzzle velocity.

@Yoozername, I read that captured Polish 75mm AP shells also did not have tracers. So when used in captured French 75mm guns extraordinary numbers consumed when engaging enemy armor.

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Re: Early HEAT Ammunition

#21

Post by Mobius » 26 Oct 2016, 20:59

Ha! I found an easy way to determine the dispersion from just knowing the 'Training' accuracy number for German guns. Just look it up in another German table. Since the 'Training' number is only based on dispersion and target size there is no other math to do. (Saves messing with standard deviations, Zs and squares like I did at first ) So in the example of the two aforementioned HEAT shells.
1. 75mm/L24 HL round Training @ 1000m = 92%; @ 1500m = 61%.
2. 75mm/L48 HL/C round Training @ 1000m = 85%; @ 1500m = 42%.

Using the Firing Table for the German 88mm KwK 43 AP we find that 92% corresponds to a dispersion of 0.6/0.8.
Using the Firing Table for the German 88mm KwK 43 AP we find that 85% corresponds to a dispersion of 0.7/0.9.
and so on.
(This works as long as the horizontal and vertical ratio is the same for both shells. But if we knew that we wouldn't need this method.)
Attachments
88L71-accuracy.jpg

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Re: Early HEAT Ammunition

#22

Post by Yoozername » 26 Oct 2016, 22:07

@Yoozername, I read that captured Polish 75mm AP shells also did not have tracers. So when used in captured French 75mm guns extraordinary numbers consumed when engaging enemy armor.
That is interesting. The tracer allows the gun crew to sense the fall of shot, and therefore correct it. Much like "closing the loop" in a control system. Having shots land short, there may be an indicative "splash", but long shots flying over give nothing. The penetration value given in the above report for the (p) rounds seem to indicate that for good side shots, the T34s could be battled out to 500 meters or so. At that range, range estimation is not that big a factor, and the higher velocity would make hits more frequent. Still, it kicked way too much firing AP.

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Re: Early HEAT Ammunition

#23

Post by Christian Ankerstjerne » 26 Oct 2016, 22:09

Yoozername wrote:Germany had a copper shortage even before the hostilities started. And, no, I was not referring to the price.
Far from everyone refer to the raw material situation, though; a lot of people consider the monetary costs to be the most important one.
Mobius wrote:(This works as long as the horizontal and vertical ratio is the same for both shells. But if we knew that we wouldn't need this method.)
Sadly, we can't count on the ratio to be the same for different guns.

8,8 cm Pzgr. 39/43
500 m: 0.2x0.2 (1:1)
1000 m: 0.3x0.5 (1:1.7)
1500 m: 0.5x0.7 (1:1.4)
2000 m: 0.7x0.9 (1:1.3)
2500 m: 0.9x1.1 (1:1.2)
3000 m: 1.0x1.4 (1:1.4)

4,7 cm Pzgr. 36 (t)
500 m: 0.2x0.2 (1:1)
1000 m: 0.4x0.4 (1:1)
1500 m: 0.4x0.8 (1:2)
2000 m: 0.6x1.4 (1:2.3)
2500 m: 0.8x2.2 (1:2.8)
3000 m: 1.2x3.4 (1:2.8)

In some cases, such as Nebelwerfer rockets, the ratio would even change so that the length was greater than the width at close range, while the opposite was true at long range.

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Re: Early HEAT Ammunition

#24

Post by Yoozername » 26 Oct 2016, 22:30

BDV wrote:Were HEAT shells expensive?
HEAT shells, almost all things considered, and viewed from many different points (materials, machining, time-consumption, labor skills, etc.) were very inexpensive.

AP rounds, meaning Pzgr 39 type rounds (APHECBC), were very expensive in terms of alloys needed, metal working (including quenching and machining), skilled labor, fuzing, testing and scrapped items. The Germans made HEAT for almost any caliber that might use it (over 75mm bore). This included captured weapons, infantry guns, etc.

All things considered, HEAT rounds were very usefull and data shows that even the Pak 40 used them in great numbers at first. Certainly a savings to KO a light tank with a HL round then use a Pzgr 39.

Pre-war, there was a 'copper-war' meaning nations were scarfing up this resource and the Germans were getting peeved. The great demand for copper was world wide as electrical power, electronics, as well as weapons and ammunition demanded this resource. The USA was also into this 'war' of course.

HEAT rounds using copper would have given better penetration and much like Tungsten, it was a lucky nation that could directly mine it.

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Re: Early HEAT Ammunition

#25

Post by Yoozername » 27 Oct 2016, 06:16

Ha! I found an easy way to determine the dispersion from just knowing the 'Training' accuracy number for German guns. Just look it up in another German table. Since the 'Training' number is only based on dispersion and target size there is no other math to do. (Saves messing with standard deviations, Zs and squares like I did at first ) So in the example of the two aforementioned HEAT shells.
1. 75mm/L24 HL round Training @ 1000m = 92%; @ 1500m = 61%.
2. 75mm/L48 HL/C round Training @ 1000m = 85%; @ 1500m = 42%.
You really believe these numbers? That is, that these two weapons, firing the same projectile, would behave this way?

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Re: Early HEAT Ammunition

#26

Post by Mobius » 27 Oct 2016, 07:00

Yoozername wrote:
Ha! I found an easy way to determine the dispersion from just knowing the 'Training' accuracy number for German guns. Just look it up in another German table. Since the 'Training' number is only based on dispersion and target size there is no other math to do. (Saves messing with standard deviations, Zs and squares like I did at first ) So in the example of the two aforementioned HEAT shells.
1. 75mm/L24 HL round Training @ 1000m = 92%; @ 1500m = 61%.
2. 75mm/L48 HL/C round Training @ 1000m = 85%; @ 1500m = 42%.
You really believe these numbers? That is, that these two weapons, firing the same projectile, would behave this way?
Weren't you the one that said the first HEAT shell was probably a jury-rigged HE shell? Maybe the later ones were constructed more to deliver a better HEAT jet and were not balanced for long range stability. It is the only data we have.

As for the numbers themselves they probably are as close as they could get with slide-rule accuracy. Note in the 88mm table 0.5/0.6 is 97% accurate while in the 75mm/L48 firing table 0.5/0.6 is 99% accurate. [corrected 10/27/16]
Last edited by Mobius on 27 Oct 2016, 20:50, edited 1 time in total.

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Re: Early HEAT Ammunition

#27

Post by Yoozername » 27 Oct 2016, 17:14

Yes, they are modified HE shells.

Some data...
7,5 cm Sturmkanone 37 L/24 penetration of armour at 60 degrees slope, distance 500 m:

Granate 38: 45 mm
Granate 38 HL/A: 70 mm
Granate 38 HL/B: 75 mm
Granate 38 HL/C: 100 mm

(From Wolfgang Fleischer's Die deutsche Sturmgeschütze 1935-1945)

Compared to the 7,5 cm L/24 Panzergranatpatrone Rot:
100 m: 41 mm (at 60 degrees slope)
500 m: 39 mm (other sources say 38 mm)
1000 m: 35 mm
1500 m: 33 mm
2000 m: 30 mm

(from Encyclopedia of German Tanks of World War II by Peter Chamberlain & Hilary Doyle)

Hl/A: a rounded steel cone with the aluminium pipe running through up till the duplex detonator under the nose fuze.
Hl/B: Has a tapered steel cone with an aluminium pipe crimped to it.
Hl/C: has a tapered zinc cone with a pipe made of one casting piece. The cone is connected with the steel explosives container, housing the main charge.

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Re: Early HEAT Ammunition

#28

Post by Yoozername » 27 Oct 2016, 17:17

1. 75mm/L24 HL round Training @ 1000m = 92%; @ 1500m = 61%.
2. 75mm/L48 HL/C round Training @ 1000m = 85%; @ 1500m = 42%.
Basically you are saying that the L24 (KWK 37) had not only superior accuracy over the L48 (KWK 40), but actually acceptable accuracy that far exceeds the Germans own guidelines for using the ammunition.

http://www.panzerworld.com/tank-combat-firing-methods

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Re: Early HEAT Ammunition

#29

Post by Yoozername » 27 Oct 2016, 17:36

This shows a cutaway drawing of the later HL/C (I believe it is a Nz P designation in German documentation). Note it has a tracer. I do not believe this drawing is entirely correct. It is from a Allied document and is a representative drawing.

edit: Note the 'FES" as seen on many German manufactured rifled projectiles. This designates that it use a sintered iron/wax driving band. Yes, the Germans didn't want to waste copper on the driving bands.

Edit: The German designation is a 7,5 cm Gr Patr 38 HL/C (Nz P)

Image
Last edited by Yoozername on 27 Oct 2016, 18:06, edited 1 time in total.

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Re: Early HEAT Ammunition

#30

Post by Yoozername » 27 Oct 2016, 17:46

The usual suspects...

Image

The design progression shows the conical shape giving way to the rounder half-spherical liner, the better standoff , the better materials (zinc), improved 'spit-back'.

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