High explosive shells in late war panzers

[historygeek2021]

By 1944, it seems that all German tanks were made with high velocity guns designed primarily to take out enemy tanks. This is in contrast with the beginning of the war, when the Panzer IV was deliberately designed with a low velocity, short barrel gun to minimize the thickness of the shell's walls, thereby allowing a greater amount of explosives to be packed into the shell. With the late war high velocity guns, the amount of explosives that could be fit into the shells would be reduced, thereby reducing their effectiveness against infantry and other soft targets.

Can anyone refer me to any material that addresses this issue and whether any German officers identified it as a problem in the late war years? Or was it generally not a big problem, and the high explosive shells were still adequate against soft targets?

[ThatZenoGuy]

By 1944, it seems that all German tanks were made with high velocity guns designed primarily to take out enemy tanks. This is in contrast with the beginning of the war, when the Panzer IV was deliberately designed with a low velocity, short barrel gun to minimize the thickness of the shell's walls, thereby allowing a greater amount of explosives to be packed into the shell. With the late war high velocity guns, the amount of explosives that could be fit into the shells would be reduced, thereby reducing their effectiveness against infantry and other soft targets.

Can anyone refer me to any material that addresses this issue and whether any German officers identified it as a problem in the late war years? Or was it generally not a big problem, and the high explosive shells were still adequate against soft targets?

Curiously the Panthers 75mm HE shells had more explosives than the low velocity shells of earlier guns, likewise the 'long' Panzer 4 gun also had more explosives.

[historygeek2021]

By 1944, it seems that all German tanks were made with high velocity guns designed primarily to take out enemy tanks. This is in contrast with the beginning of the war, when the Panzer IV was deliberately designed with a low velocity, short barrel gun to minimize the thickness of the shell's walls, thereby allowing a greater amount of explosives to be packed into the shell. With the late war high velocity guns, the amount of explosives that could be fit into the shells would be reduced, thereby reducing their effectiveness against infantry and other soft targets.

Can anyone refer me to any material that addresses this issue and whether any German officers identified it as a problem in the late war years? Or was it generally not a big problem, and the high explosive shells were still adequate against soft targets?

Curiously the Panthers 75mm HE shells had more explosives than the low velocity shells of earlier guns, likewise the 'long' Panzer 4 gun also had more explosives.

Can you give a source and explain how this worked?

[historygeek2021]

I looked up the shell weights on wikipedia and ThatZenoGuy is correct, the late-war high explosive shells contained more explosives than the early war shells. They did this by making the shells longer, increasing the overall weight of the shells.

I am still wondering if there were any commentaries by soldiers in the field about the effectiveness of the high explosive shells fired from high velocity guns. Anyone have any information?

[ThatZenoGuy]

I looked up the shell weights on wikipedia and ThatZenoGuy is correct, the late-war high explosive shells contained more explosives than the early war shells. They did this by making the shells longer, increasing the overall weight of the shells.

I am still wondering if there were any commentaries by soldiers in the field about the effectiveness of the high explosive shells fired from high velocity guns. Anyone have any information?

Well a higher velocity gives you better long ranged accuracy. Less time for various factors to make the shell go off course, and its easier to range with a high velocity gun.

On the flipside if you merely want to pummel a building, infantry position, etc with HE, you don't 'need' high velocity and you can get more shells off with a lower velocity weapon. 40 high velocity HE shells will be outperformed by 60-80 lower velocity ones of equal power.

The fragmentation pattern of a higher velocity gun might also be more of a 'cone' rather than a larger radius, that might make it more or less effective depending on where the target is relative to the shell impact.

[critical mass]

By 1944, it seems that all German tanks were made with high velocity guns designed primarily to take out enemy tanks. This is in contrast with the beginning of the war, when the Panzer IV was deliberately designed with a low velocity, short barrel gun to minimize the thickness of the shell's walls, thereby allowing a greater amount of explosives to be packed into the shell. With the late war high velocity guns, the amount of explosives that could be fit into the shells would be reduced, thereby reducing their effectiveness against infantry and other soft targets.

Can anyone refer me to any material that addresses this issue and whether any German officers identified it as a problem in the late war years? Or was it generally not a big problem, and the high explosive shells were still adequate against soft targets?

Curiously the Panthers 75mm HE shells had more explosives than the low velocity shells of earlier guns, likewise the 'long' Panzer 4 gun also had more explosives.

Can you give a source and explain how this worked?

They just lowered the i.V. if the H.E. shell by reducing the amount of preopellant in the cartridge, so that a high velocity gun could very well employ a medium velocity H.E. shell. The gun sights reticles had special marks for A.P. A.P.40 and H.E. shells.

I don´t really know why the british didn´t attempt the same until very late. Its a simple and highly effective solution for the problem at hand.

[historygeek2021]

They just lowered the i.V. if the H.E. shell by reducing the amount of preopellant in the cartridge, so that a high velocity gun could very well employ a medium velocity H.E. shell. The gun sights reticles had special marks for A.P. A.P.40 and H.E. shells.

I don´t really know why the british didn´t attempt the same until very late. Its a simple and highly effective solution for the problem at hand.

Thanks. What is i.V.?

[ThatZenoGuy]

They just lowered the i.V. if the H.E. shell by reducing the amount of preopellant in the cartridge, so that a high velocity gun could very well employ a medium velocity H.E. shell. The gun sights reticles had special marks for A.P. A.P.40 and H.E. shells.

I don´t really know why the british didn´t attempt the same until very late. Its a simple and highly effective solution for the problem at hand.

Thanks. What is i.V.?

Initial Velocity.

[Yoozername]

By 1944, it seems that all German tanks were made with high velocity guns designed primarily to take out enemy tanks. This is in contrast with the beginning of the war, when the Panzer IV was deliberately designed with a low velocity, short barrel gun to minimize the thickness of the shell's walls, thereby allowing a greater amount of explosives to be packed into the shell. With the late war high velocity guns, the amount of explosives that could be fit into the shells would be reduced, thereby reducing their effectiveness against infantry and other soft targets.

Can anyone refer me to any material that addresses this issue and whether any German officers identified it as a problem in the late war years? Or was it generally not a big problem, and the high explosive shells were still adequate against soft targets?

I think your basic premise is incorrect. That is, that the 'low velocity' 7,5 cm L24 weapons did not develop high pressures. The reason for this is that they are achieving a fairly high velocity of 450 M/s in a shorter length barrel than a 7,5 cm L43/48 (which had a MV of 550 M/s). I believe most of the war, they shared the same Spgr 34, or very much equivalent? I have the data somewhere. I don't think it actually differed that much between the two rounds as far as HE. So, as far as the projectile stresses are concerned, they are about equal for the same distance (and time) while in the barrels. The pressure drops off considerably for the L43/48 at the point where the L24 achieves MV. That is, when the shell leaves the L24 tube.

The Pzgr round for the L24 weapons did have more Pzgr L43/48 rounds, something like 80 grams vs 17 gr. But there were reasons other than any 'high pressure issues.

[historygeek2021]

I think your basic premise is incorrect. That is, that the 'low velocity' 7,5 cm L24 weapons did not develop high pressures. The reason for this is that they are achieving a fairly high velocity of 450 M/s in a shorter length barrel than a 7,5 cm L43/48 (which had a MV of 550 M/s). I believe most of the war, they shared the same Spgr 34, or very much equivalent? I have the data somewhere. I don't think it actually differed that much between the two rounds as far as HE. So, as far as the projectile stresses are concerned, they are about equal for the same distance (and time) while in the barrels. The pressure drops off considerably for the L43/48 at the point where the L24 achieves MV. That is, when the shell leaves the L24 tube.

I never said anything about "high pressures." I repeated a point made by Boris Kavalerchick, a former mechanical engineer for the Soviet armed forces, in Tanks of Operation Barbarossa, page 54:

"The low muzzle velocity of its shell in this case was not a shortcoming; on the contrary, it contributed to its effectiveness. The low loads on the shell in the process of firing made it possible to make it thin-walled and to increase its explosive charge. Thus, its high-explosive force and fragmentation effect increased significantly."

The Pzgr round for the L24 weapons did have more Pzgr L43/48 rounds, something like 80 grams vs 17 gr. But there were reasons other than any 'high pressure issues.

What were the reasons?

[ThatZenoGuy]

To note a thinner wall makes faster smaller fragments, thicker walls make slower larger fragments. At least until you start getting pre-formed fragment sleeves and stuff like that.

More explosives equals more blast but not necessarily more damage to some targets.

[Yoozername]

I never said anything about "high pressures." I repeated a point made by Boris Kavalerchick, a former mechanical engineer for the Soviet armed forces, in Tanks of Operation Barbarossa, page 54:

"The low muzzle velocity of its shell in this case was not a shortcoming; on the contrary, it contributed to its effectiveness. The low loads on the shell in the process of firing made it possible to make it thin-walled and to increase its explosive charge. Thus, its high-explosive force and fragmentation effect increased significantly."

Well if that is what you are basing the supposed 'thin wall' theory on, it is wrong. The walls were not thin on the 7,5 cm KWK Spgr round (called Gr. Patr.). So, the premise is wrong. He is also not entirely correct about the relationship between filling and shell thickness.
This primary source shows the weight of the shell, and the explosive weight for the L24 7,5 cm ....

....compare to the 7,5 cm Spgr for KWK 40 (and StuK 40)...virtually the same. I believe the 7,5 cm Spgr 34 was adapted to the L24 weapons used later in the war also.

75kwkgrpatr.jpg (131.42 KiB) Viewed 1618 times

[Yoozername]

Actually, German documentation shows very little difference in the Spgr for the Pak 40, 'panther', L48/43, and L24 explosive projectiles. Most commonly showing 680-690 gm explosive, and also a 35 gm booster. Considering the weights are all listed as 5.74 Kg, the actual filling is not bad at all at over 12%. if someone has any primary sources regarding some 'long' bodies, please post them.

Shells in this caliber are really fragmentation generators. If you would be killed by the 'blast', you would have been shredded by the fragments anyway. the materials used in the casing, and the force of the explosive, interplay to generate what size(s) and velocity of fragments generated. It is always a spread of sizes and no two shells generate the same spread. Something like mortar shells, especially if using just cast iron, and having a good % of HE (15% or better), create very deadly areas (more circular than clover leaf). But something like a 88 mm shell, which was designed for AA work, is fairly thick walled and is meant to create large fragments way up high where blast effects are diluted by the thin air. but it still works on the ground.

[Yoozername]

The 'panther' Spgr 42 is well known for having two driving bands...but who sees another distinctive feature?

[ThatZenoGuy]

The 'panther' Spgr 42 is well known for having two driving bands...but who sees another distinctive feature?

pVquiz.jpg

I don't see it. ;(((