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The difference between Holladung / shaped charge A, B & C.

pzgr40

pzgr40

Well-Known Member
Premium Member
The difference between Holladung A, B & C for the German 7,5 cm KwK 40 and StuG 40 cartridges can be observed in the following way:

HL-A: a round (sphere) cone with a long thin aluminuium flame guidance pipe ending over the duplex cap. Penetration; 70mm steel plate.

Hl-B: a conical steel cone with a larger dia. aluminium flame guidance pipe connected to the base of the cone by a full rim. Penetration; 75mm steel plate.

Hl-C: a full cast zinc alloy cone, cone and flame guidance pipe are one cast piece. Penetration; 100mm steel plate.

All three types use the PIBD (Point Ignited Base Detonated) method of ignition (also called "spit back fuze"). This means the AZ38 nose fuze which is activated upon impact sends a flame down the pipe into the booster in the base of the projectile. This will enshure the detonation wave of the explosive charge moves from the base to the nose.
The B type has a disc with a hole above the shaped charge cone, the C type has a "funnel" type disc/pipe combination above the cone. On some websites it is claimed to be anti spall, however this is incorrect. The disc and funnel disc are meant to protect the shaped charge cones from splinters from the duplex detonator during impact, and so prevent a premature detonation which makes the shaped charge useless.

The A & B type use the Aluminium AZ 38. This is a simple fuze with a firing pin being fixated in the upper position by six centrifugal segments held inward by an expanding spring ring. Upon firing , the centrifugal segments are thrown outward, -overriding the expanding spring ring-, releasing the firing pin. Above the firing pin, a wooden hammer pin is placed, which hammers the firing pin into the duplex detonator upon impact.
The C type uses the AZ38 St, the steel version of the AZ38, simplified for production purposes. It has however a longer hammer pin, kept under a pressed steel cap.

Regards DJH
 

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  • Cartridges Hl A, B, C for KwK 40 and StuG 40.JPG
    Cartridges Hl A, B, C for KwK 40 and StuG 40.JPG
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  • Hl A, B and C for KwK 40 and StuG 40.JPG
    Hl A, B and C for KwK 40 and StuG 40.JPG
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Another example of the HL B as used in the French M1897 Field gun. Many of these guns were captured in 1940 in France. These guns were pressed into German service and ammunition range was adjusted to German requirements.
Due to the low velocity of the projectile, the M1897 gun was not suitable for anti tank purposes, however by producing a HL B type shell for the gun, it had some degree of anti tank capability.

Regards, DJH
 

Attachments

  • 7,5cm Hl B for French M1897 gun.jpg
    7,5cm Hl B for French M1897 gun.jpg
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The HDv 481/186 and HDv 119/319 list 4 shape charge projectiles for the french gun:
7,5cm Gr 38 Hl/A (f)
7,5cm Gr 38 Hl/B (f)
7,5cm Gr 38 Hl/C (f)
7,5cm Gr 15/38 Hl/B (f)

For the projectiles 7,5cm Gr. 38 Hl/A and Hl/B both AZ 38 and AZ 38 St are listed.
For 7,5cm Gr 38 Hl/C only AZ 38 St. (this applies for both KwK40 and 97/38)
If AZ 38/1 reached the troops I do not know.

Bob
 
Hi Bob,
Thanks for the added info. I did not know there were four HEAT types for the M1897.

Regards, DJH
 
Wolch said:
maybe somebody know how to read such charts ?
Click to expand...
At a guess, starting at the far left column and going from top to bottom and when required left to right:

Explosive used = Z 135;
Liner angle = 10 degrees;
Stand-off from the 100 mm plate angled at 60 degrees (i.e. effective thickness 200 mm) = 60 mm;
Liner thickness = 1 mm;
Hole dimensions (presumed format) 'entrance/exit (depth of penetration if no exit occurred)' = 22 mm/ no exit (12 mm)

The format then repeats downwards for different liner thicknesses, and repeats across (to the right) for different arrangements.
 
sgdbdr said:
Whole documents here :
Click to expand...
yes, decide to make PDF's for simplicity of use

Eggburt1969 said:
At a guess, starting at the far left column and going from top to bottom and when required left to right:

Explosive used = Z 135;
Liner angle = 10 degrees;
Stand-off from the 100 mm plate angled at 60 degrees (i.e. effective thickness 200 mm) = 60 mm;
Liner thickness = 1 mm;
Hole dimensions (presumed format) 'entrance/exit (depth of penetration if no exit occurred)' = 22 mm/ no exit (12 mm)

The format then repeats downwards for different liner thicknesses, and repeats across (to the right) for different arrangements.
Click to expand...

thank you!

https://imgur.com/a/X0Z7gv8

Gr38C liner

https://imgur.com/a/33Vs4DZ

zinc variant
 
pzgr40 said:
The B type has a disc with a hole above the shaped charge cone, the C type has a "funnel" type disc/pipe combination above the cone. On some websites it is claimed to be anti spall, however this is incorrect. The disc and funnel disc are meant to protect the shaped charge cones from splinters from the duplex detonator during impact, and so prevent a premature detonation which makes the shaped charge useless.
Click to expand...

from german report about it

Experiments and developments to increase the performance of shaped charges by adding nozzles.

In the French loot stocks, shaped charge grenades were found for the first time that had a nozzle ring above the shaped charge (Fig. 1). Since these were test grenades that could not be fired and since no other shaped charge grenades were found, it can be assumed that no experiments were carried out with these grenades and that the idea of increasing performance by adding nozzles was not pursued further.

Based on these projectile finds, explosive tests were carried out with rigid nozzles that were placed in front of the explosive charge. Two factors proved to be particularly important here: the height of the nozzle and the nozzle angle (Fig. 2).

The height of the nozzle depends on the best distance of the shaped charge from the plate surface, since, as is generally known, the best penetration performance is not achieved when it is placed directly on the plate. There are various maximum values that depend on the shape of the cavity. For example, the following values were found for the conical shape. The most favourable blasting distances are around 20, 40 and 100 mm. With greater distances, the dispersion of the impact power increases significantly. It is striking that this increase in power when the explosive devices are raised can only be detected in lined cavities.

Blasting series with different dissipation angles were also examined. Here, too, no steady curve can be identified. Up to a nozzle angle of 50, the power increases, then drops at 60°, reaches a maximum value at around 75° and slowly drops again up to 90°.

The absolute increase in power of these rigid nozzles compared to explosive charges without nozzles was up to 7% of the penetration depth during both firing and blasting.

The resulting impacts are characterized by round, cylindrical shapes and smooth edges on the plate impact, which were previously mostly curved.

During the firings it became apparent that small differences in the dispersion of the explosive charge, the dimensions of the projectile, etc., greatly influence the nozzle angle, or, conversely, that every most favorable nozzle angle is only fixed for a precisely defined explosive charge structure. Since the practical dispersion is already higher, it was not possible to produce a "standard nozzle" on this basis.

If one assumes the finding made by Wa F (construction officer Dr. Trinks) that the casings at the upper end are penetrated by the vapor stream and then act as a nozzle, the idea of attaching a metal disk to the open end of the hollow charge, which must first be penetrated by the vapor and then clings to it in the shape of a nozzle, is a reasonable one (Fig. 3).

Tests have shown that this assumption is correct. By suitably weakening this nozzle disc, it is possible to ensure that it bends centrally and without major power losses.

The nozzle disc fulfils two functions, strictly speaking. Since the outer parts of the vapor never reach the density of the inner parts during the resulting vapor surge, they are held back when the vapor surge hits the nozzle disc in front of them, and suddenly break through when they reach the appropriate density. Whether this is a simple blockage phenomenon or is due to reflex movements still requires careful investigation. In addition to the nozzle effect, a similar effect is likely to be the function of every cavity lining in general.

Once the vapor surge, which was initially compressed in this way, has broken through the nozzle disc, the edges of the vapor are again compressed, thereby increasing the overall density.

It has been shown that the variation in the impact power decreased when the nozzle plate was fitted. The absolute increase in power when using nozzle disks is around 10 - 15% of the penetration depth. It depends on the shape of the cavity. For example, it is better for cavity shapes with poorer directivity, e.g. a hemisphere, than for a cone. It seems correct to assume that roughly the same absolute power is achieved for different cavities (hemisphere, bell, cone) by fitting nozzle disks.

The thickness of the nozzle plates increases with increasing caliber. The most suitable thickness for the 7.5 cm Gr. 38 Hl/B is 3.5 mm.

To enable better bending and to prevent deformation of the nozzle disk at high speeds, it was provided with a hole in the middle. This hole also serves to facilitate the ignition transmission. After the hole was fitted, almost consistent results were achieved at speeds of up to 480 m/sec.

Based on these tests, nozzle-shaped steel cones were placed on the explosive charges, which narrowed towards the projectile head (Fig. 4). The cones, whose angle was 75°, were coated with explosives. The purpose of this arrangement was as follows:

In this arrangement, the attached "explosive nozzle" works in a component that runs opposite to the main vapor flow when it breaks down the forces, i.e. it causes the main vapor flow to narrow. The tests to date have only produced a slight increase in performance, which is, however, nowhere near as great as that achieved with rigid nozzles. Tests with more powerful explosive disseminators have not yet been completed.

In summary, after these basic tests, the use of nozzle attachments for shaped charges is pointed out, which result in an increase in performance without any significant change to the charges. Since the tests have only been running for a short time, this report is intended to provide an incentive for further collaboration and further investigations.
Click to expand...

twEmI61.jpeg

is there any more info ?

french shells which was captured is Mohaupt design

yvCLHXu.png
 
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