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I don't know if it was posted here before, but I found something interesting over the IAA (International Ammunition Association) forum: forum.cartridgecollectors.org

I highly recommend occasionally visiting as they post some very interesting and most often to the point findings.

This one is supposedly a 105mm APFSDS for smoothbore cannons (the experimental 105mm SB), made by IMI and has a very unusual marking. Some of the comments contain information about the markings, and although they conflict with each other, they're very interesting.

Note the AP/TP and DM33A2/MOD markings. 

photo1_zps46fadc44.jpg

 

photo3_zps356907a7.jpg

 

 

I suggest reading their discussion in that forum post : https://forum.cartridgecollectors.org/t/german-israeli-105mm-ap-tpfsds-t-sabot-petals-info-neede/14505

 

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New here, but I've followed this thread (and Mech Warfare) for a good while.   I attend the United States Military Academy and it is branch week here. Armor brought an M1A2 SEPv2 which, whil

Now for the DM23. 

After the 1982 war, the Israeli M111 Hetz APFSDS gained fame for piercing the armor of T-72 tanks. Although there are many conflicting reports as to whether T-72 ever met APFSDS armed tanks (Magach, Sho't or Merkava) or were only engaged with TOW missiles (9 destroyed in single ambush IIRC), there is at least the reported and yet undenied (as far as I've seen) story of T-72 armor tests in Kubinka against the M111 Hetz that was obtained through a captured M48 tank. The discovery of that KEP shell was reportedly so surprising that the USSR decided to give Syria a large batch of its domestic version of T-72(AV) and not the usual downgrades.

The M111 may or may not have been developed in cooperation with German company Rheinmetall (they have managed to keep it a secret after all, so chances are slim), but we do know Germany acquired license for its production under the name DM23. I would also like to note at this point that IMI and Rheinmetall seem to have a very high level of cooperation at least in KEP development and production, as many of their products seem to be identical (entire 105mm family at least, and DM63 and M338 are allegedly the same). 

Here are again photos from the IAA forum: https://forum.cartridgecollectors.org/t/israeli-105mm-apfsds-projectile-made-for-germany-as-dm23/13534

 

IMG_4649_zps5f5a2523.jpg

 

IMG_4657_zps2f4e59d7.jpg

 

IMG_4654_zpse5cb45e6.jpg

 

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  • 3 weeks later...
  • 2 weeks later...

Regarding to the DU vs WHA discussion from the first page:

 

The document "Definition and uses of RHA equivalences for medium caliber targets" by T. Farrand, L. Magness and M. Burkins provides some new information on how much better DU is as a penetrator material (at least in case of medium calibre ammo). It can be found here.

 

Medium calibre APFSDS rounds made from DU have superior armor penetration into semi-infinite targets, but they don't have better armor perforation compared to WHA ammunition! Penetration measurements focus on how deep the penetration channel of a projectile extends into a non-penetrated target. Perforation on the other hand looks at how thick the armor can be, that the round still punches a hole through it. While penetration is commonly measured, perforation values might have more application in real life (What is the benefit of a round going a bit deeper into the armor, if it is not perforated?).

 

Vcb4w3n.png

9AiXpSn.png

So in other words: DU penetrates armor more effectively, but WHA can cancel out this effect (in some cases, depending on the failure mechanism) by breaking off more material at the back of a plate. Supposedly this is the result of DU's adiabatic shearing ("the self-sharpening") causing the penetrator mass to shrink much more (speculated in another random document), thus the relative perforation ability of a DU projectile would shrink while penetrating into (steel) armor.

This is all valid for medium calibre ammo against steel sloped at 60°, but I think in general it seems plausible that this can scale up to tank calibres in theory.

 

X57DM1l.png

The conclusion of the document is something I can agree very well: "The protection level of a threat vehicle cannot be defined by one RHA-e value; it depends on several factors: penetrator material, penetrator geometry, target configuration, RHA penetration, and the method and RHA baseline used. It has been shown that the RHA-e for one medium caliber target evaluated with several projectiles can vary by more than 100%."

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43 minutes ago, SH_MM said:

 

Medium calibre APFSDS rounds made from DU have superior armor penetration into semi-infinite targets, but they don't have better armor perforation compared to WHA ammunition!

 

Not really - with what is presented in that paper, it would be correct to state that the specific DU long rod tested performed the same as the specific WHA long rod tested, but as the paper did not even state that the penetrator weight was similar I don't feel it's justified to extrapolate to all medium calibre APFSDS rounds. It could be the WHA round had a finer L:D ratio, assuming that they were designed to be fired from the same gun - there is not enough information to make a comparison beyond the projectiles tested, whatever they might be

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Given that Farrand and Magness have tested equally sized DU and WHA rods in multiple different papers (most US tests are focused on keeping the dimensions constant despite changing density), it seems very likely that they kept the same dimensions for both rods. That would be a 9.7 mm diameter, 130 mm "medium calibre" APFSDS. Most of the plotted data comes from "Deformation Behaviour and its relationship to the penetration performance of high density KE penetrator materials" which unfortunately seems to be not available for free.

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Something from the Armored Warfare forums.

 

Seeing as I'm not having any trouble with the link, I'll paraphrase; PISH stands for Piercing Intelligent Squash Head. Another 80s experiment (so firing it from a 140mm gun is quite fitting), they were developed as HESH that could differentiate between soft and hard targets. Specifically, they were designed to just explode on impact on soft targets but act as regular HESH against hard targets. Here's a cutaway 120mm PISH shell, with a 40mm Bofors given for scale.

pish.jpg

The success of the PISH shells was contingent on developing a fuse that could tell the different between soft and hard. They couldn't, so the project was shelved. Of course AW is set 50+ years after the 80s, so just maybe...

On another note, could you post a link to the preliminary patch notes Alzoc? I can't find them anywhere.

 

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1 hour ago, Ramlaen said:

It seems like the fuse issue could be circumvented with a modern pre-programmable one.

 

I was thinking something similar.  Fusing has come a long way since the 1980s, it might be possible to make PISH work.  Bu then again, I'm not sure why you would want to.

 

1 hour ago, Xlucine said:

Image recognition to determine how 'hard' the target is would be cool. It wouldn't offer much over programmable SAP-HE, but it would be really cool

 

Yep.  I can't think of any reason to keep HESH around.

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PISH sounds a lot like a sort of ancestor of the modern PELE and ALP rounds. Or at least it does to me with my admittedly very limited knowledge base when it comes to tanks, AFV's, their guns, and ammunition.

 

Somebody please help me out here, am I seeing a sort of ancestral connection where there isn't one?

 

Or have I actually made a valid point?

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Yeah, I was thinking more about ALP than PELE itself and I know that the mechanism by which they function is pretty different.

 

I was just wondering if PISH technology is somewhere in the conceptual family tree which eventually spawned PELE/ALP.

 

However, if this isn't the case it isn't the case, and I don't know how one would go about proving this one way or another without interviewing design teams to see what their inspirations were.

 

I'm trying to get a handle on this armored warfare thing but some days I feel like the more I learn the less I know.

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17 minutes ago, SH_MM said:

Actually PELE has pretty bad penetration unless it's PELE-pen (PELE fitted with an additional penetrating core behind the PELE assembly). PELE is mostly suited for larger calibres or for aircrafts, otherwise FAPDS/FAPIDS is better suited.

Exactly. PELE needs to penetrate armour to work, so you need to know how stuff works. HESH is more like "I don't know how penetration works so I'm just going to sling explosives at the enemy".

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  • 2 weeks later...

50th shades of the CL 3254M and  M711/8 MK.2 :)

 

Orginall IMI:

 

ZGC2Mys.jpg

 

PpyoMLk.png

 

 

 

Indian copy:

 

mZStjzj.jpg

 

SnE9AR9.jpg

 

 

Indian: 1st copy:

 

boo9tZK.jpg

 

U3BRE1Y.jpg

(on left)

 

 

PpSv97 VETRA (upper one)

LtxPaqf.jpg

 

 

Serbian clone:

 

QXjLjeM.jpg

 

 

 

Polish one (PRONIT)

 

EoHwk4W.jpg

 

YxB56Q6.png

 

 

 

It's interesting how the same sabot and penetrator can give difrrent values in sevral manufacurer data :)

 

Polish trials shown 520mm RHA on plate slopped at 60@ 

Slovakia shown >550mm RHA

Czeh shown - "more then 500mm RHA"

etc

 

 

 

And next puzzle:

 

"New Nexter 125mm munition APFSDS":

abOqYm9.jpg

 

Claimed to have up to 600mm RHA (lol, yeh, sure...)

 

And "old" Pakistani POF 125mm APFSDS:

I0VSM1Y.jpg

 

Looks quite simmilar - is't it?

POF round gave 460mm RAH at 0. so in 60. it will have slighty more then 520-530mm RHA

 

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@Methos

 

It may be interesting - relatio between lenght and penetration in APFSDS:

 

Hqsv5rJ.jpg

 

 

KO4RD6X.jpg

 

TVEcCSk.jpg

 

pffXNa3.jpg

 

 

Im interesting if we can assume that in @60 RHA plate  penetration shoud be equal to monoblock penetrator lenght whit Vdrop circa 1650-1700m/s?

 

If it's some siple "thumb rulle" :-) (joke) then we can assume some german round penetration:

YDhaJIw.jpg

 

So DM33A1 ca 510mm RHA at 60@

DM43 ca 600mm RHA at 60@

DM53 ca 680mm RHA at 60.

And BTW - polish WITU is still count penetration whit 75% not NATO (50%+1) so digrense is circa 8%, ant this ca.8% form value above is:

470mm RHA, 560mm RHA, etc...

 

 

 

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    • By SH_MM
      [title image]
       
      Hollow charges and armor protection - their alternating progression
       
      The term "hollow charges", which is commonly used in German, is not very accurate for the explosives so called. The somewhat more general American term "shaped charge" is a better description of the measures necessary to achieve the desired effects with these charges. Apart from the explosives used by glider pilots at Fort Emeal, it is of great importance for the vast majority of the extensive and versatile range of applications of shaped charges developed since the Second World War that their suitably shaped surface is covered with a layer of inert materials, preferably metals.  The individual elements of the liner are accelerated to velocities of several km/sec and, through special selection of the initial shape and dimensions, it is possible to transform these liner bodies into projectile-like structures which are best suited to combat the respective target.
      This possibility of adapting the effector to the structure of the target to be engaged is very important for the use of hollow charges, but the application potential of these charges, given their early and impulsive nature, is far from exhausted by what has been developed in this field so far. This is particularly true when it comes to combating targets whose design is already tailored to protect against the known hollow charges.
      This will be explained in more detail below; in addition, examples will be used to illustrate the many different ways in which explosives can be used to obtain targeted effects and counteractions.
       
      The effect of explosive devices attached to armour panels - the "spalling effect"
       
      In most cases of using detonating explosives, the energy released by the detonation is transferred to inert materials. In the case of armour plates on which explosives are detonated, the direct effect is relatively small. Although the detonation pressure exceeds the strength of the armour material many times over, the material goes into a state of fluidity and is slightly pressed in at the surface - something similar happens when damp clay is pressed. The depressions that occur are small because the time during which the detonation pressure is sustained and the material is in a flowing state is very short. This only lasts until the relaxation of the highly compressed explosive decomposition products towards the free surface of the detonator has taken place. If, for example, an explosive layer of 2 cm thickness is placed on an armour plate, the impact time on a surface element of the plate during detonation is about 2/800000 sec, i.e. 2.5 µsec. During this time only a slight displacement of the plate material can occur. The example of an explosive layer applied to the surface of an armour plate and detonated there is also suitable for explaining a phenomenon that is very important and is referred to several times in the context of the present comments:
       
      [Figure 1]
       
      Under certain conditions, material parts detach from the rear side of the armour plate and are propelled at quite high speed into the space behind the plate. This so-called " spalling effect " occurs whenever a limited area in a body, where the material is under very high pressure, reaches a free surface of the body (see figure 1). There, the material parts compressed under high pressure relax and advance perpendicular to the surface. The relaxation is thus associated with acceleration. While the relaxation spreads into the interior of the pressure area, all material parts that have been compressed by it are accelerated. If the relaxation wave reaches the rear end of the pressure area, i.e. the zone in which the material particles are not compressed and therefore remain at rest, the parts that have been set in motion by the relaxation break off at this point and continue their motion only outside, provided that the tensile stress that occurs exceeds the tensile strength of the material.
      In the case of the spalling effect, one observes a separation of disc-shaped plate parts on the back of an armour plate exactly opposite the surface covered by the explosive on the upper side (see also Figure 15). This surface must not be less than a certain size, because the accelerated, spalling parts must not only overcome the tensile strength of the detachment from the inner plate parts, which remain at rest, but also the shear stresses at the edge of the spalling plate. In general, this is only then the case when the diameter of the overlying explosive layer exceeds the thickness of the armour plate, otherwise a " bulge" appears on the underside of the plate.
      The effect of the " squash head " projectiles is based on this spalling effect. The explosive in the bullet cap is released when the projectiles impact on of the armour plate is spread and then detonated. 1)
       
      The effect of unshaped, uncontained explosive charges in the free atmosphere

      If an uninsulated explosive device is detonated in the open atmosphere without any special design or arrangement, its effect is relatively small at a distance from the source of detonation. Although the pressure behind the detonation front, which in modern explosives can reach speeds of is advancing at about 8 km/sec, is quite high. It is in the order of several hundred thousand atmospheres, but it rapidly decays as it spreads in all directions, distributing energy and momentum over areas that grow quadratically with distance.
      By contrast, special arrangements, which should be mentioned here because they are to a certain extent related to hollow charges, can be used to achieve a sufficient pressure effect even with unshaped, unchecked explosive charges at greater distances, for example against flying targets.  If, for example explosive charges are arranged at the corners of a regular polygon and detonated simultaneously, a very effective superimposition of the pressure occurs on the axis of symmetry of the arrangement at distances of up to several diameters of the polygon - in the so-called Mach area. Towards the end of the Second World War, the possibility of using such charge arrangements from the ground against enemy aircraft flying in pulks had been considered. In model tests with 6 charges of 50 kg trinitrotoluene (TNT) each, regularly distributed on a circle of 100 m diameter, a pressure of about ~15 bar was measured 350 m above the ground in the vicinity of the axis of symmetry.
       
      Protective effect of multilayer armour

      In order to be protected against the spalling effect of squashing head projectiles and similarly acting warheads, it is advisable to provide armour which consists of at least two layers with a gap between them. For this reason alone, the development of anti-tank ammunition was therefore based on paying special attention to multilayered armour. The requirement for penetration of structured armour with air gaps is also indispensable in other respects. The same conditions apply, for example, when an armour is hit by a plate covering the running gear or by a "skirt" attached to the running gear. In the case of more or less abrupt impact, the point at which the ignition of a shaped charge warhead takes place can then be up to several metres away from the point at which its main effect should begin. In addition to standard single-layer targets, the testing of hollow-charge ammunition therefore includes targets consisting of several plates spaced at certain distances from each other (see Figure 2).
       
      [Figure 2]
       
      In principle, the mode of action of hollow charges meets the above-mentioned requirements very well, much better than is the case with conventional impact projectiles. When a kinetic projectile hits a armour surface, a high pressure is created in both the armour material and the projectile. Starting at the tip, a pressure condition is built up in the bullet, which leads to the phenomenon described earlier in the treatment of the spalling effect on the free surface of the bullet. Tensile stresses occur which begin to tear the bullet body before it has penetrated the target surface. They can cause the bullet to disintegrate into individual parts after penetrating the first plate, which are then stopped by a second plate of a multilayer target (see Figure 3 a and b).
       
      [Figure 3]
       
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      The flow of the material particles associated with the displacement of the target material ends at the free surface. Partly at the upper side, partly at the lower side of the armour plate and partly also at the already created penetration channel, which is subsequently narrowed again slightly.
       
      The following jet particles not consumed during penetration continue their path after passing through the penetration channel and act on obstacles that are on their path. If they hit another armoured plate, they can continue the penetration process there undisturbed.
      In contrast to the behaviour of the compact kinetic projectile, the individual elements act on the armour one after the other, independently of each other, and it does not seem so important at first whether the armour is massive or in separate parts, because a disturbance at the tip of the projectile does not affect the following parts.
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      [Figure 4]
       
      If now diagonally incident subsequent particles reach the previously created penetration channel running approximately perpendicular to the surface, they find a much reduced cross-section for their passage compared to the vertical incidence (see Figure 5). There is thus an increased probability that they will come into contact with the wall as a result of path variations, as a result of which their contribution to the penetration performance is lost. The affected particle disintegrates explosively, since - as described above - the high pressure occurring during wall contact induces tensile stresses on the free surface of the particle, causing it to burst. In Figure 6, a TRW image converter camera is used to illustrate how a steel ball of 2 mm diameter is sprayed after it has penetrated a very thin plastic film at very high speed. Figure 7 shows the piece of a hollow charge jet in which a similar burst was triggered on a particle by touching the wall. As can be seen from the figure, the small debris of the disintegrated particle spreads sideways to the direction of the beam, apparently away from the wall that was touched. It is important that the propagation of these fragments into the free space behind the plate is possible. At massive targets this free space is not available, the particle splinters would be held together and their impulse could contribute to the penetration even if the particle had touched the wall before. That's why it's important, armoured plates and air gaps of certain thickness should follow each other.
       
      [Figure 5, figure 6 and figure 7]

      This leads to bulkhead arrangements which, when hitting the wall at an angle, cancel out the effects of a high portion of the hollow charge jet due to the increased probability of the jet particles touching the wall and their subsequent disintegration into the gap. The weight of the armour required for this, in relation to the unit area, is considerably less than in the case of solid armour. It is essential that this provides increased base protection against both balancing projectiles and shaped-charge ammunition, and it is noteworthy that this effect occurs in both cases by inducing the decay phenomenon on impact at high velocity. However, in the case of a balancing projectile, the entire mass of the energy carrier is captured by the destructive tension waves on first impact, whereas in the case of a hollow-charge jet only the mass portion corresponding to the respective impacting jet particles is captured.
       
      Measures to avoid disturbance of the shaped charge jet

      However, it is not clear why rear particles of the hollow charge jet must necessarily come into contact with wall elements of the penetration channel created by the previous ones. Should it not be much more possible to ensure that the particles
      aligned very cleanly and without "staggering" movement exactly on the cavity axis? However, this means that the slightest deviations from central symmetry must be avoided in the structure of the hollow charge. The whole rigor of this requirement is that it relates not only to the dimensions of the charge, but also includes the homogeneity of the materials used and that - as has already been shown - even differences in the size and orientation of the crystals in the explosive and in the copper of the liner have an influence. This requirement is even more stringent if one takes into account that the properties of the crystals mentioned above change over time, i.e. as they age, and that changes are also triggered during processing. A very sensitive influence can also be expected from the way the detonation is initiated.
      With the aforementioned and similar requirements with regard to precision, the production of hollow charges has set goals whose pursuit in the past has already brought about significant progress with regard to the generation of an undisturbed hollow charge jet during detonation, and in the future, through the tireless efforts of research and technology, even further perfection can be expected. In addition to this somewhat utopian-looking reference, however, it must be emphasized that the hollow charge principle is very flexible and includes a wealth of other possibilities for counteracting disturbances which oppose the effective targeted use of the explosive energy released during detonation. For example, it is not necessary for the hollow charge jet to dissolve into a number of particles as it progresses. Some of the irregularities in the behaviour of the particles will only develop during the tear-off process and can be avoided if the hollow charge jet is constructed in such a way that it does not tear.
      The reason for the dissolution of the hollow charge jet into a number of particles of different velocities is that the individual jet elements already have a different velocity when they are formed. In the case of the hollow charges currently in use, there is a velocity gradient in the beam from about 8-10 km at the tip to about 2 km at the end.The consequence is that the jet is constantly stretched as it progresses and eventually dissolves into more or less parts according to the strength properties of the material .2)
       
       
      The programmed shaped charge jet

      By special selection of the parameters of a hollow charge (type and density of the explosive, dimensions and shape of the cavity, wall thickness and material of the cavity lining, shape as well as wall thickness and material of the casing, position and extension of the ignition elements) it can be achieved that differences in the velocity of the individual elements of the jet are prevented at all.
      The relationship between the distribution of mass and velocity in the jet and the charge parameters was already known shortly after the discovery of the
      the lining of the cavity achievable effect by Thomanek quite detailed results. 3)
      This connection is achieved by following each individual sub-process during the detonation of the charge and the deformation of the liner by calculation. When the detonation front reaches the individual zones of the liner body, the material there enters a state of flow under the influence of the detonation pressure and is accelerated inwards. The speed at which the lining elements are accelerated depends on how long the pressure remains at the zone under consideration or, which comes to the same effect as how far the outer surface of the detonator is from this point. Thus, the influence of the width of the explosive coating on the velocity of a panel is obtained.
      For example, consider a cylindrical charge with a cone as a cavity and a diameter of 8 cm. The time required for the dilution wave to reach the top of the cone from the outer surface is then 4 cm/approx. 800000 cm/sec, i.e. approx. 5 microseconds; in the central zones of the cone with an explosive coating of 2 cm, this time is only half as long and the impulse transmitted to the lining elements by the detonation pressure in this time is therefore half as large.
      Of course, the speed also depends on the wall thickness of the lining body at this point and the density of the lining material.  The initial velocity of the lining elements can be specifically influenced by a suitable choice of the wall thickness and it can change at will between the tip and base of the lining cone. One speaks of "progressive" or "degressive" liners, depending on whether the wall thickness increases or decreases towards the base. The influence of the liner's wall thickness/explosive coverage ratio then has a further effect on the jet elements that are emitted when the liner zone converges on the cavity axis. In addition, the mass and velocity of the jet elements formed depend on the angle at which the convergence takes place, i.e. the opening angle of the cavity. Peak angles result in high velocities for small masses, and the opposite is true for obtuse angles.
      The previous remarks should serve to explain, at least by way of indication, how it is possible to determine the dependence of the distribution of mass and velocity in the jet on the charge parameters. With the knowledge of these interrelationships, it now seems possible to create projectile-like structures from the cladding bodies, in which the initial length and the distribution of mass and velocity over this length are predetermined, i.e. the hollow charge jet can be programmed.
       
      Up to now, almost all attempts have been made to obtain a jet with the greatest possible penetration capacity. This led to the familiar design forms: cylindrical on the outside, cavity for example 60° cone with copper liner, initiation of the detonation now often by detonation wave deflection at the rear edge of the detonator, whereby better use of the explosive volume and higher beam tip velocities are achieved (compare also Figure 16). The resulting beam is then a constantly stretched structure with a velocity of up to 10 km/sec at the tip and about 2 km/sec at the end, which is followed more slowly by the rest of the cladding mass, the so-called "slug". 4)
      As already mentioned several times, the differences in the velocity of the individual beam elements cause the initially coherent structure to be broken up into a sequence of particles. Nevertheless, very good results have been achieved with the described type of charges, especially against massive targets.
      Penetration depths of up to 6 charge diameters have been achieved. In contrast, when using targets with air gaps, the distance travelled in the massive parts of the target is greatly reduced. In the future, requirements for the performance of hollow-charge ammunition should be geared to these reduced amounts; this would mean that modern hollow charges should be developed to penetrate structured targets rather than exaggerated penetration performance in massive targets. An attempt should be made to program the hollow-charge jet, i.e. to adapt it to the structure of the target.
      In the following we will try to explain by means of examples that there are many possibilities to modify the beam of the currently used hollow charge.

      A completely different motion sequence of the particles of the beam from this type of charge can be obtained by replacing the centrally symmetrical ignition by a (one-sided) eccentric one.The individual beam particles then no longer move one behind the other on the cavity axis, their paths point in a fan-like manner in different directions (compare Figures 8a and b) 5) The following example is intended to show how even a slight change in the cavity shape can noticeably influence the beam and its effect.  Figure 9a shows a cladding body whose shape can be roughly described as a cone which ends at the base in a spherical zone. Figure 9b shows the penetration channel of an externally cylindrical charge produced using this liner.
       
      [Figure 8 and figure 9]
       
      The explanation for the peculiar shape results from the velocity distribution in the hollow jet. The front part of the jet comes from the cone-shaped part of the cavity and corresponds to the jet from a cone, which stretches as it advances. For the subsequent jet elements, which originate from the spherical zones at the base, it is decisive that the tangent at the cavity becomes steeper and steeper towards the base. The consequence is that the successive jet elements become faster and faster towards the rear, thus approaching each other and leading to a thickening of the jet in this rear area. On impact, the effect is increased in the form of a widening of the penetration channel.
      While with the hollow charge described above, a concentration of energy occurs in the rear jet section, it is also possible to achieve this in the front jet section. For this purpose, the cavity must be spherical at the apex and end in a cone at the base (see Figures 10a and b). The penetration channel is wide at the top and has the shape of a hemisphere followed by a narrow conical part. 6)
      If the cavity, which is essentially delimited by a cone, is spherical at both the apex and the base, the penetration channel will consist of a wide part at the armour surface, followed by a narrow conical part and a further widening at the end. Following these examples, it should be considered possible that the effectiveness of the individual sections of the hollow charge jet can be determined in quite a different way, especially if it is taken into account that other parameters of the hollow charges can also contribute to this by their specific choice.
       
      [Figure 10]
       
      As explained in the previous section, other velocity distributions are possible in addition to the velocity gradient in the jet of the commonly used hollow charges that leads to rupture. It is also possible to achieve that all beam elements have the same velocity, provided that the relevant charge parameters are adjusted to it in each zone of the cavity. If, for example, the wall thickness of the cladding is selected in such a way that it is in the same ratio to the corresponding width of the explosive coating for all zones, the cladding elements of all zones receive the same initial velocity on detonation and thus also all the beam elements that are separated from them when flowing together on the cavity axis.
      As a result, the jet is represented here by an "overlong projectile" with a rather high velocity. A sketch of the principle of such a charge is shown in Figure 11. The nozzle-shaped body attached to the base has the purpose of preventing the decomposition by-products from coming into direct contact with the free atmosphere when the base zone is accelerated, thus avoiding a premature drop in pressure. In a similar way, other causes of disturbance are to be avoided, whereby a number of experiments are always necessary before a principle path can be realized.
       
      [Figure 11]

      Instead of a single rod-like projectile, a sequence of several such rods can be obtained in which the individual elements have the same velocity, with the velocity of the rods differing from each other.
      In addition, from the special solution of the identical velocity of all beam elements, transitions to the common hollow charge with the large velocity gradient in the beam can also be developed. In particular, the case can also be realized in which the difference in the velocity of the following beam elements is so small that the beam is only broken when all obstacles of the target have been overcome. How such a continuous beam reacts to protective measures that disturb a particle-dissolved jet is still to be investigated. In any case, the disturbances caused by the rupture process are avoided here (compare Figure 12).
       
      [Figure 12]

      Also, the range of possible variations in the structure of the shaped charge jet is so wide that an adaptation to very different target compositions seems possible. Not insignificant is the fact that the energy of the effect carriers from a hollow charge can be distributed in a targeted manner to mass and velocity, i.e. the jet can obtain a greater mass at the expense of the velocity of its elements and vice versa.
      As investigations have shown, the protective effect of certain materials depends on the speed of the projectiles. 7) However, such measures need not refer to the entire jet, but can be limited to parts of it, for example to the front or rear parts of the target.
      A special group of shaped charges has not been mentioned so far, namely those with a flat, especially blunt conical cavity. ln contrast to the pointed conical cavity, the attainable velocities are lower here. The speed of the structure previously referred to as the jet is no longer very different from that of the so-called following slug. It can be achieved by methods which will not be discussed in detail here, that the jet and slug components - i.e. the entire mass of the liner - merge into an at least temporarily coherent structure. lf the difference in the speeds of the front and rear parts is sufficiently small, it is absorbed by internal expansion work, and a projectile with a uniform speed of about 2000 m/sec is created. Figure 13 shows a series of such projectiles from charges with a flat cavity, using X-ray flash images.
       
      Figure 14 shows a section through a captured specimen of cohesive projectiles. Such projectiles are particularly characterized by stable flight at long distances and have already found 'a versatile application today, especially as a replacement for natural fragments (see also cover picture and Figure 15).
       
      [Figure 13, figure 14 and figure15]
       
      In connection with the efforts to combat future targets, which may be unknown at present, it should be mentioned that it is possible and possibly very useful to arrange projectile-forming hollow charges in a special way one behind the other. If this is done taking into account all the side effects of the detonation, and if such an arrangement is ignited appropriately, one obtains a sequence of projectiles flying one behind the other at fairly high speed, the mass of which is considerably greater than that of particles of the hollow charge jet.
      It is also possible to combine a projectile-forming charge with a jet-forming charge with an acute-angled cavity. Figure 16 shows such a charge, also known as "tandem charge".
      It was designed to create a strong follow-on effect inside the tank. On detonation, the jet from the rear charge penetrates through an opening in the apex of the front flat-cone charge. Only after this has been done is this charge also detonated; the flat liner body is formed into a projectile which follows the jet from the rear charge through the channel created by it and comes into effect there depending on the intended purpose.
       
      [Figure 16]
       
      These examples are intended to show that there are almost no limits to the imagination when it comes to exploiting the potential inherent in the principle of forming effective projectiles by transferring explosive energy to inert materials. There are many ways to develop explosive charges that can be effective against complex targets and do not necessarily require a gun to reach the target, but can be used in warheads of missiles. Of course, there will always be possibilities to achieve sufficient protection by suitably constructed armour. What should be particularly emphasized here, however, is the view that there is hardly likely to be a miracle cure for all types of shaped charges and that, apart from a temporary predominance on one side or the other, there will probably continue to be mutual efforts to perfect shaped charges on the one hand and protective armour on the other.
       
    • By Ronny
      I see many knowledgeable members here so i decided to make an account to ask some question
      According to many historical accounts, the armor of WW II battleship is very thick: can be between 410-650 mm of steel
      Thick enough that they can even resist penetration  from 12-16 inch canon 


       
      Compared to these massive round, it is probably obvious that missiles such as Harpoon, Exocet will do little or nothing against the armor belt: No penetration and probably nothing more than a small dent.
      Anti tank missiles such as AGM-65, AGM-114 or Brimstone can penetrate the armor but all their warhead will do is penetrating a tiny hole into the massive battleship, it likely will hit nothing significant given that a battleship have massive volume of space). Furthermore, i heard space armor is extremely effective against HEAT warhead as well).
       
      But what if the two are combined? HEAT + explosive warhead: aka BROACH.
      With a frontal shape charged and secondary follow through bomb
      This is the working principles of the system:


       
      BROACH was designed to help small cruise missile penetrate bunkers. So i have some question:
      1- Because concrete and soil are very brittle, unlike steel, I think the precursor charge likely much drill bigger hole in them than it can drill on steel armor belt of a battleship, so even if we use missile with BROACH warhead to hit a battleship, it won't drill a hole big enough to allow the secondary warhead to pass through. Is that a correct assessment?
      2-  Looking at the cutaway of the missiles. How come the detonation of the frontal shaped charge doesn't damage/destroy the secondary warhead or at very least propel it to the opposite direction? 
       
      3-  Can supersonic missiles such as Agm-88 (Mach2) , Asmp-A (Mach3) , Rampage , Asm-3 (Mach 3) , Hawc (Mach 5) penetrate the armor belt of a battleship? or they simply don't have enough velocity and density?
       
       
       
    • By Molota_477
      M1 CATTB
      pic from TankNet.
      I feel uncertain whether its cannon's caliber was 140mm or not, I found a figure at the document AD-A228 389 showed behind, which label the gun as LW 120.But in many ways I've found its data in websites all considered to be 140mm.

      AFAIK,the first xm291(140)demonstrator was based on xm1 tank, and the successor was the''Thumper'' which was fitted with a new turret look like the CATTB but still m1a1 hull(Maybe it was CATTB's predecessor? )

      I will really appreciate if anyone have valuable information to share
    • By Domichan
      Hello all,
      I apologize for the fact that my first post is a question. I am a Dutch collector of medium and large calibre AP ammunition and I recently bought an 105mm APFSDS-T projectile, that is marked with the designation DM53. The 120mm DM53 is well known, but I cannot find any information on the 105mm DM53. I do know the IMI M426/DM63 round exists, for I have seen pictures of that, which would indicate that a DM53 would exist as well, in accordance with the way German ammo designations go. Questions to Rheinmetall, the Bundeswehr and various collector groups have remained unanswered. 
      Among the experts here, is there anyone who has information on this type of APFSDS-T Round?
      Thank you in advance,
      Domichan
       

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