Early HEAT Ammunition

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BDV
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Early HEAT Ammunition

#1

Post by BDV » 24 Oct 2016, 12:50

Hello

How effective were the early forms of HEAT ammunition in combat, for both Germans (75 mm L24 gun) and the Italians (the "effeto pronto" for the 47mm gun); 1941-42?

German work on putting bigger, longer guns on tanks suggest that they were not impressed with the results, but they may have had other reasons.
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Re: Early HEAT Ammunition

#2

Post by Stovepipe » 24 Oct 2016, 12:57

The early rounds pretty much required a perfect 90 degree hit to function correctly and I don't think they had the penetrative ability of later rounds. a 47mm HEAT round would have been fairly small and probably only effective against thinner side plate rather than frontal plate.


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Re: Early HEAT Ammunition

#3

Post by BDV » 24 Oct 2016, 14:23

Were HEAT shells expensive?
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Re: Early HEAT Ammunition

#4

Post by Christian Ankerstjerne » 24 Oct 2016, 21:22

HEAT ammunition had some inherent problems in that the muzzle velocity was lower than for AP ammunition, which meant that the trajectory was steeper and that the target had to be led more.

As for whether it was expensive, you need to define 'expensive'. Unlike APCR ammunition, it didn't contain any scarce raw materials.

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Re: Early HEAT Ammunition

#5

Post by BDV » 25 Oct 2016, 11:18

HEAT does use copper for the plasma jet, that may make it less affordable.

M Wittmann did score some kills against KV tanks, presumably using HEAT. So I was wondering whether this was the exception or the rule; as this was the only AFV option that could defeat KV1 armor consistently in 1941.

Historically a great deal of effort was put forth to develop kinetic-dependent gun projectiles and the platforms able to carry the guns shooting them.
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Re: Early HEAT Ammunition

#6

Post by Sheldrake » 25 Oct 2016, 13:11

HEAT rounds lose a lot of their effectiveness if the round is spinning as any wobble will disperse the jet of molten metal. Solving this leads to expensive ammunition with slipping driving bands.

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Re: Early HEAT Ammunition

#7

Post by Stovepipe » 25 Oct 2016, 14:41

the advantage of a HEAT round is that it is velocity-independent; look at the panzerfaust round, big and slow but very effective. From what I've read, one of the main problems with making HEAT rounds from the guns of 1941 was the fusing and using existing shell cores as the basis for the round. Recoilless rifles existed before WW2 and they knew how to make them work but making a functional HEAT round using a tank gun was harder to achieve.

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Re: Early HEAT Ammunition

#8

Post by Sheldrake » 25 Oct 2016, 14:52

Stovepipe wrote:the advantage of a HEAT round is that it is velocity-independent; look at the panzerfaust round, big and slow but very effective. From what I've read, one of the main problems with making HEAT rounds from the guns of 1941 was the fusing and using existing shell cores as the basis for the round. Recoilless rifles existed before WW2 and they knew how to make them work but making a functional HEAT round using a tank gun was harder to achieve.
Hence the trend toward smooth bore tank guns post war - apart from the British who would rather have a rifled tank barrel for accruacy than a HEAT round. APFSDS continues the path started in WW2 with APDS

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Re: Early HEAT Ammunition

#9

Post by Stovepipe » 25 Oct 2016, 14:58

The British were obsessed with HESH rounds and of course, inflicted with not-invented-here syndrome. Everyone else is using smooth bore 120mm and they insist on a rifled barrel and are now unable to mod up the Chally 2 to accept a smooth barrelled gun, because of storage issues.

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Re: Early HEAT Ammunition

#10

Post by Mobius » 25 Oct 2016, 15:15

Christian Ankerstjerne wrote:HEAT ammunition had some inherent problems in that the muzzle velocity was lower than for AP ammunition, which meant that the trajectory was steeper and that the target had to be led more.
Actually, the early HEAT of the 75mm/L24 had a higher muzzle velocity than the AP. Which would make it slightly more accurate.
The early 75mm HL shell didn't penetrate very much but was more than the AP shell beyond 300m. Now, the HL/A round gave the 75mm gun a fighting chance against the early heavy Soviet tanks.

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Re: Early HEAT Ammunition

#11

Post by Christian Ankerstjerne » 25 Oct 2016, 20:21

BDV wrote:HEAT does use copper for the plasma jet, that may make it less affordable.
While copper is more expensive (currently about 15 times), much less is used for the copper liner than for the solid steel shot.
BDV wrote:M Wittmann did score some kills against KV tanks, presumably using HEAT. So I was wondering whether this was the exception or the rule; as this was the only AFV option that could defeat KV1 armor consistently in 1941.
The ammunition production for the 7,5 cm Kw K was not divided into different types, so I can't tell you exactly when HEAT ammunition for this particular gun became available, but HEAT ammunition for other guns with considerable HEAT ammunition production (7,5 cm Pak 40, 7,5 cm Kw K 40, 7,5 cm Pak 97/38) did not begin to become available at the front until the late summer and early autum of 1942.
Sheldrake wrote:HEAT rounds lose a lot of their effectiveness if the round is spinning as any wobble will disperse the jet of molten metal. Solving this leads to expensive ammunition with slipping driving bands.
But this still doesn't answer which was more expensive, or more importantly, resource-intensive.
Mobius wrote:Actually, the early HEAT of the 75mm/L24 had a higher muzzle velocity than the AP. Which would make it slightly more accurate.
Stability doesn't depend on velocity but on inertia. Light, high-velocity shots will be less stable than heavy, low-velocity shots. I don't have the dispersion values for the 7,5 cm Kw K, but comparing the 7,5 cm Pzgr 39 with the 7,5 cm Pzgr 40 of the 7,5 cm Kw K 40, the dispersion of the Pzgr 39 at 1000 meters is better (0.5x0.6 meters) than that of the Pzgr 40 (0.6x0.7 meters).

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Re: Early HEAT Ammunition

#12

Post by Yoozername » 25 Oct 2016, 20:47

HEAT rounds were less accurate than normal HE. The internal layout and cavity leads to this.

Most HEAT rounds from rifled weapons slightly compensate for the spinning by the actual 'cone' shape. It is likely that if you detonated one statically, meaning no spin, it might not be as effective as when spinning.

Most German reports cite the 500-600 meter range as the maximum. They also claim large consumption of ammunition. Not just to hit, but also to destroy the enemy AFV.

A little known fact, also cited by the Germans, is that HEAT has no tracer. They were based on HE rounds and HE has no tracer either (no matter what that wargame shows...).

I don't believe many nations could afford to use copper liners btw. Many use brass or aluminum or even soft steel.

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Re: Early HEAT Ammunition

#13

Post by Mobius » 25 Oct 2016, 23:35

Christian Ankerstjerne wrote:Stability doesn't depend on velocity but on inertia. Light, high-velocity shots will be less stable than heavy, low-velocity shots. I don't have the dispersion values for the 7,5 cm Kw K, but comparing the 7,5 cm Pzgr 39 with the 7,5 cm Pzgr 40 of the 7,5 cm Kw K 40, the dispersion of the Pzgr 39 at 1000 meters is better (0.5x0.6 meters) than that of the Pzgr 40 (0.6x0.7 meters).
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.

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Re: Early HEAT Ammunition

#14

Post by Christian Ankerstjerne » 25 Oct 2016, 23:38

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.

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Re: Early HEAT Ammunition

#15

Post by Christian Ankerstjerne » 25 Oct 2016, 23:44

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.

And yes, range estimation was critical for HEAT ammunition, but it seems that the artillery and anti-tank schools were only just starting to work together in 1943. I doubt the strained relationship between the artillery and armor branches.

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