Shells Of WWII

[Wolfgang_Otto]

Questions.

German anti-tank shells of WWII, didin't most have an explosive charge? Was it supposed to explode on the OUTSIDE of the tank or INSIDE?

What about American/Russian/British anti-tank shells? Did they have explosive charges?

[YankeeDog]

You really have to get down to specifics about individual calibers and shells if you want to know exactly what's going on here. I don't have an extensive enough library at home to give you a full answer, but based on what I've read and returned to the library, I can give you some generalizations. I'm sure others more knowledgable (and with more immediately accesible references!) can note exceptions and details in these statements.

Technically, an AP shell by definition has an explosive charge - that's why it's called a shell. If it's solid metal, techically it's AP shot.

In general, the Germans did use HE "Burster" charges as part of many of their AP rounds. These HE charges, usually located near the base of the AP round, were designed to explode inside the AFV so as to increase the damage an AP round caused once inside the vehicle. Achieving detonation inside the vehicle basically involves a very short delay impact fuse - the fuse is ignited by impact with the armor, and then after a preset delay (we're talking thousandths of a second here), explodes the charge, at which point the shell is hopefully somewhere inside the vehicle.

The Americans, Russians, and British also used "burster" charges in AP rounds. I have read accounts about fighting in North Africa that noted problems with early war American and British AP shell fuses - the burster charges would apparently often fail to work. These same accounts noted that the german fuses seemed to be quite reliable. I know much less about the reliability of Russian HE shell fuses.

An interesting side note: adding a burster to an AP round usually decreases it's penetration capability - the HE displaces some of the metal, reducing the shell's weight and to a certain extent it's structural integrity. So the designer has to strike a balance between the potential amount of damage the shell will cause if it penetrates, and making sure the shell is heavy and strong enough to penetrate the armor in the first place.

Cheers,

YD

[Wolfgang_Otto]

Ok thanks a bunch!

How common were they?(guess?) And are they depicted in Combat Mission II?(ordered...not arrived yet)

Know any additional sources I can consult about this?(books...websites...)

[ December 21, 2002, 10:19 PM: Message edited by: Wolfgang_Otto ]

[Stalin's Organ]

They are quite common, and are accounted for in CMBB - some AP shells have small or large bursters too, making their effect less or greater respectively.

Try searching Google for somethign like "armour piercing ammunition"

[Bastables]

British used solid AP shot till the end of the war. The British even went to the extent of removing the HE from 7,5cm AP shells recived from the USA.

[ December 21, 2002, 10:41 PM: Message edited by: Bastables ]

[Wolfgang_Otto]

Thanks a bunch guys.

So let me get this straight...

British only like solid shot.

Americans used both.

Germans used both.

Russians used both.

How common were they to the individual nations?

And what about HEAT rounds? They are only good aganist soft armor correct? Half-tracks and the like.

[ December 21, 2002, 10:48 PM: Message edited by: Wolfgang_Otto ]

[gunnersman]

What about "Hollow Charge" rounds or what we know today as HEAT rounds(High Explosive Anti-Tank)? There were assault guns with HC rounds right? They would explode outside of the tank except they are designed in such a way as to direct of majority of the explosive force in one direction once contact was made, in effect punching a hole through armor with force many times that of an AP round of the same caliber (depending on the gun of course).

[ColdSober]

You can read a bit more about Armor Piercing Ammunition here

[Wolfgang_Otto]

Great info! Thanks a ton!

[YankeeDog]

Originally posted by Wolfgang_Otto:

[snip]

And what about HEAT rounds? They are only good aganist soft armor correct? Half-tracks and the like.

HEAT is a totally different way of penetrating armor. HEAT stand for High Explosive Anti-Tank. A normal AP shell relies on kinetic energy to penetrate armor - basically, it's a big piece of steel accelerated to very high speed. If it's heavy enough and hits the armor going fast enough, it will punch through the armor and bounce around like a pinball inside the tank. As noted before, and HE "burster" is simply intended to increase the damage the round causes inside the tank, but does not improve penetration capabilty (in fact, it may hurt it).

HEAT is a totally different thing. a HEAT round is a high-explosive round with a roughly conical-shaped cavity hollowed out of the front of the explosive charge. This cavity is then lined with a liner of copper or aluminium. The acutal physics are pretty complicated, and there's lots of details such as the size and shape of the cavity, the distance of the explosive charge from the armor at the time of detonation, etc. that affect a HEAT shell's penetration abililty in a addition to the size of the shell and the weight of the explosive charge.

Generally speaking, when a HEAT shell detonates, the metal liner around the conical cavity gets vaporized and focused into a narrow jet of VERY hot gaserous material moving VERY quickly (5500 m/s is not unusual). It is this jet of hot gasses, rather than the shell itself, that punches though the armor. Once the hot gases get inside the AFV, they injure or kill crew members, ignite ammo etc.

HEAT rounds are very capable of penetrating even the heaviest armor. Furthermore, since a HEAT round's penetration capability is not dependent on velocity, they don't necessarily require a really big gun with lots of muzzle velocity to penetrate thick armor, and their penetration capability does not degrade with range.

the biggest problem with HEAT shells is accuracy. If spin is imparted on a HEAT projectile, the spin acutally degrades penetration. The physics reasons for this are again complicated (it has to do with rotational momentum if you're curious), but the end result is that HEAT rounds do much better when fired from low-velocity guns that don't spin their projectiles as quickly, or from launchers that don't spin their projectiles at all, such as rocket-launched, spin-stabilized projectiles like the Panzershreck. This is why most tanks and AT guns in WWII used high-velocity kinetic energy AP shells rather than HEAT rounds to knock out enemy tanks - it doesn't matter how much armor you shell can penetrate, if you can't hit the target, it's no good! For certain platforms, such as lightweight IAT weapons like the Panzershreck and the "self-defense" rounds for low-velocity guns like howitzers, HEAT rounds make more sense.

A final note: While the concept behind the shaped charge was first discovered in the late 19th century, WWII was the first conflict where it was used on a large scale. As a result, the quality of HEAT rounds varies considerably from combatant to combatant, and from year to year. Don't be surprised if the AP performance of a given caliber of shell suddenly changes when you move from 1942 to 1943 or whatever. In general, for a given shell size, German HEAT rounds are more capable than allied shells at penetrating armor - they were a bit ahead of the curve on the physics of HEAT penetration.

Cheers,

YD

[Olle Petersson]

Originally posted by YankeeDog:

... If spin is imparted on a HEAT projectile, the spin acutally degrades penetration. ... This is why most tanks and AT guns in WWII used high-velocity kinetic energy AP shells rather than HEAT rounds to knock out enemy tanks ...

... WWII was the first conflict where it was used on a large scale. As a result, the quality of HEAT rounds varies considerably from combatant to combatant, and from year to year. ...

I think the last note is the most important, and the real reason for not making widespread use of HEAT in WW2. Notice that in the '50ies HEAT became the standard ammo type, and AP/APDS almost disappeared. The advent of reactive armour lead to a come-back for kinetic energy AP, in the form of APFSDS.

During the WW2 HEAT rounds were still of a fairly experimental design.

The effect of a HEAT charge depends a lot on design and precision in production.

For maximum effect it is necessary to have total symmetry (down to individual molecule) around the length axis. This type of symmetry can't be acheived in large scale production today, and was far off during WW2.

Individual modern HEAT charges, produced under laboratory conditions, can penetrate more than eight calibres of armour plate. Regular modern HEAT rounds can penetrate 5-7 calibres. WW2 HEAT would be 1-3 calibres, with large variation between rounds of the same batch.

One way to overcome the problem with rotation is to use a warhead slightly smaller than the gun tube, and have it fit to a sleeve that can rotate freely. This way the sleeve rotates and provide stability while the warhead have nearly no rotation at all. This is the way the ammo for the Carl Gustav 8.4 cm RR is designed.

Cheers

Olle

[SgtMuhammed]

The spin not only affects HEAT rounds but APFSDS (Sabot) rounds as well by hindering the ability of the penetrator to bite into the armor. This is the primary reason modern armies have gone nearly exclusivly to the smoothbore cannon for tanks. Some of the attempts to eliminate spin from rifled cannon were pretty neat like rotating rings around the shell.

It was the discovery that AP shells with smaller bursting charges were better at piercing armor that propted most armies to go more with AP Shot. This was further fueled by the realization that if an AP slug actually entered the insides of an armored vehicle it really didn't make much difference if it exploded or not.

On the other end of the spectum you have the HESH or squash head shell that was never designed to penetrate the armor. Rather it was designed to use its explosive energy to cause internal flaking and cause casualties that way.

In a side note, it was the developement and proliferation of the HEAT warhead in everything from tank rounds to hand held rockets that led to the developement of the Chobham or composite armor that most Western MBTs now use. It is a never ending battle between offense and defense.

[flamingknives]

Challengers 1 and 2 mount rifled main guns, which fire APFSDS with rotating sleeve, HESH and smoke rounds.

Just FYI

[Stalin's Organ]

APDS never fell out of favour with anyone!

The Brit 105mm tank gun was the western "standard" for 20 years and all nationalities using it used APDS rounds.

APDS was not used by some large calibre guns mounted on light chassis - such as the French 105's and 90's mounted on armoured cars and light tanks because the chassis could not stand the recoil generated by the size of charge nedded to get an AP round up to speed.

The British tend to favour HESH where other nations use HEAT for their dual-purpose (AP/AT) round but the fact that they do probably shows that the 2 types are of relatively similar performance.

[RSColonel_131st]

This got to be the first time that someone explains to me in understandable terms how a HEAT or HC shell works. I did not know the part about the Liner.

Thanks!

As for non-exploding armor piercing...I refer to them as SABOTS...I'd still think they have their place on the modern battlefield, especially with all the reactive and composite armor around. Reactive armor in itself is also a very interesting topic I'd say.

[Shosties]

Originally posted by YankeeDog:

Generally speaking, when a HEAT shell detonates, the metal liner around the conical cavity gets vaporized and focused into a narrow jet of VERY hot gaserous material moving VERY quickly (5500 m/s is not unusual). It is this jet of hot gasses, rather than the shell itself, that punches though the armor. Once the hot gases get inside the AFV, they injure or kill crew members, ignite ammo etc.

The physical state of the jet that the liner is formed into has been attributed to all the known ones by varied authors: solid, liquid, gas, and plasma! My impression, gleened from studying a distantly related phenomenon in materials science, is that flash X-ray work experimentally confirmed that the jet is solid. The pressures produced are such that even high viscosity solids can flow extremely rapidly. Indeed, the armor is induced to flow as well at the point of impact by the jet, rather than the plug that shears off inwards by the impact of an AP shot. I believe APFSDS travel fast enough to initate penetration by flow rather than by shear in a ductile armor like RHA.

I can dig up some (open literature!) sources if anyone is interested.

[Shosties]

Originally posted by RSColonel_131st:

As for non-exploding armor piercing...I refer to them as SABOTS...I'd still think they have their place on the modern battlefield, especially with all the reactive and composite armor around. Reactive armor in itself is also a very interesting topic I'd say.

There is a difference between shot and discarding-sabot rounds. Sabot, "say-bow", is French for shoe(s?)... the sabot are inserts that encase a sub-diameter shot or dart. Once the sabot-shot/dart assembly leaves the barel, aerodynamic drag strips away the sabot.

The great thing this does is it frees the projectile from the constraint placed on conventional shot: that it must form a good gas seal with the barrel it is fired from. The projectile can be optimized for in-flight ballistics and terminal effects (pun intended).

WW2-era APDS basically slung a sub-caliber shot, not much different in shape than a full-caliber shot. The advantage then was that it flew faster, being overall lighter, but without sacrificing sectional density (roughly mass of shot/transverse cross sectional area).

To maximize sectional density, you want to evolve this into a "long rod" penetrator to pack the most mass behind the smallest impact area. Eventually, it becomes aerodynamically unstable even when spun, so you put fins on the sucker and make it a dart and de-spin it or switch to smoothbore cannon. From then on it's a struggle to keep increasing the aspect ratio of the shaft without making it so fragile as to break up if it hits at an angle.

[caligula_jones]

this is a great topic...

anyways, i wish i could find the sources, but i remember seeing pictures from the gulf war of a couple of M1A1 Abrams that had been bit a couple of times each by, but weren't taken out by hits from iraqi tank guns.

both abrams' were sitting there with APDS darts sticking out of their turret sides.

it was kind of funny: with the end of the dart (fins and all) sticking out in the air, they kina looked like NERF weapons!

shane

[ January 02, 2003, 05:00 PM: Message edited by: caligula_jones ]

[SgtMuhammed]

A friend of mine was an M1 commander in the Gulf and he told me that the Iraqi darts looked like they had just melted a bunch of pots and pans and poured them into a mold. Really poor quality stuff. Another buddy told me that the DU sabot round (which they called Silver Bullets) were so much more powerful than the normal training rounds that they lifted the tank to the middle road wheels. Then again tankers do tend to exagerate.

[Lumbergh]

Originally posted by RSColonel_131st:

As for non-exploding armor piercing...I refer to them as SABOTS...I'd still think they have their place on the modern battlefield, especially with all the reactive and composite armor around. Reactive armor in itself is also a very interesting topic I'd say.

Not to mention that crazy Russian active-antimissile defense system. It's nice to know that 60 years on, it's *still* best to have a bigass German gun.