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About tank guns and amunition, hope it will be interesting topic :-)

 

In penetration data I will base on russian sources -they are ussaly most credible (the best). I will ussaly give value for monolith steel plate slopped on 60@ - it's the best scenario for APFSDS penetrator. In sucht scenario (slopped on 60@ plate) penetration value can be bigger at even 17-20% then on 0.degree plate - this is caused by "asymmetry loads back surface" of the plate):

APFSDS%203.jpg

 

 

First:

M829

M829A1

M829A2

M829A3

M829A4

 

M829:

DOI: 1985

penetration at 2km, on plate slopped by 60@: 540-560mm RHA:

 

 

bgubJzV.png

 

 

M829A1

DOI - 1989 (in some sources - 1988) 

penetration: at 2km, on plate slopped by 60@: circa 700mm RHA

this round was to weak to overcome T-80U and T-80UD and T-72B m.1989 whit Kontakt-5 ERA, what was "suprisly" discover on tests in circa 1994. The same story was whit DM43 prototypes..

 

VSr3yom.jpg

 

M829A2

DOI - 1992

penetration: at 2km, on plate slopped by 60@: circa 740mm RHA

Fist US round whit composite sabot.

 

(lack good photos)

insted of this:

 

KE-W so M829A1 but whit WHA penetrator, and KEW-E3 so M829A2 whit WHA long rod.

TxRK8Lp.png

 

 

M829A3

DOI - 2003

penetration: at 2km, on plate slopped by 60@: propably circa 800mm RHA, but is not sure value,

round devleoped to everpas heavy ERA but whit unkown result :)

 

u9seeSN.jpg

 

 

M829A4

DOI -2016 :-)

 

penetration - no idea 

It's very interesting round

 

Fv0uWoC.jpg

 

data link is  for APFSDS round?!

I have a hypothesis...

Ok so it have data link to be programmed, it is said to be capable to defeat 3rd generation heavy ERA (Relikt, Knife, etc.) and active protection systems (hard kill). It seems that focus is primary on defeating heavy ERA. But then again, why do you need to program just a long rod fired by a big gun?

There are few options:

- Gudining the round,
- Precursor,
- "Intelligent" control over propelant charge ignition (dependant on propelant temperature, environment temperature, gun service life, range to target etc.)

And truth to be told hypothesis that there is some sort of precursor in the rod is the only hypothesis that makes sense. Control over propelant charge ignition is not needed and probably not possible at all with current technology, besides the M829A4 (and all newer US ammo types for 120mm smoothbore) use insensitive propelant charges. And it is nowhere mentioned in any document avaiable for public. Guiding the rod to target? Perhaps possible from technical point of view, but why? Again it was nowhere said that FCS for M1A2SEPv3 have ability to guide any type of rounds. And manouvering of the rod during flight means loss of a lot of energy, even if this manouvering would be done to "cheat" the APS for example.

So perhaps the option is to somehow use a precursor that is "fired ahead" of the main rod.

700.jpg


 

 

So how the rod designs looks like here? The rod is made from two segments, the "precursor" and the main rod behind it. How they are connected? it might be some sort of polymer, glue that can be weakened by heat and the release precursor, and during flight rods heat up pretty nicely.

The precursor can also be relased based on a simple difference of speed between it and the main rod, and main rod can be slowed down by some sort of additional fins (aerodynamic breaks) released at specific point programmed by FCS. In such case precuros would initiate ERA and the main rod would have a clear way to main armor of the target.

How to cheat APS tough? Counting that precursor will be qualified by APS as threat and APS will be initiated, creating a time gap in APS reaction so it won't be able to counter the main rod? Possible yes, but then there is question, if APS will just not ignore the precursor, and this might happen, now of course there is a question how dangerous is precursor itself? For a MBT or vehicle with similiar levels of protection, for it's front it won't be dangerous in most cases, sides? If they do not have any addon armor, very possible. For lightweight platforms, yeah precursor also will be dangerous.

Of course these are only hypothesis, and we will see if other nations will also design APFSDS rounds with data link. Then we might get closer to the truth. Right now, treat it as food for thoughts.

 

of course this data link coud be placed only for security resons, as one person on TankNet had wrote:

he ammunition is telling the computer what type of round it is thus reducing the bad things which can occur when the gunner thinks he's firing one type of ammunition and the loader has loaded something different.

 

:-)

 

ps. prefragmentet APFSDS during flying exist now, as smal-scale models and test object:

SbL8Rs9.jpg

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Some APFSDS marks on destroyed tanks:

 

T-72M ODS 1991:

 

kGr32W8.jpg

NvkaMqP.jpg

 

 

Separatist T-72B m.1989:

E6Tsh2O.jpg

DlPLZrq.jpg

(the most strange think is that this tank not blow out after sucht hit..)

 

 

UA Army T-64 BW after hit:

RyfkJiS.jpg

0c0luaO.jpg

 

 

well known separatist T-64BW destroyed by two APFSDS hit:

n4I3qxk.jpg

34dIWvp.jpg

 

 

Iraqi T-62 2003 OIF:

 

1st example:

wyTjGkQ.jpg

 

2th example:

JGTDTmn.jpg

 

Russian/separatist T-72BW after friendly fire to destroy damage tank:

5S8HvLa.jpg

what is interesting - fist shoot was on sucht short distance that we can see sabot mark on plate -so distance was under 50m... interesting. 

About fins marks - 3BM42 in action?

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About polish 125mm and 120mm APFSDS-T ammo.

 

In case 125mm polish army is using

3BM15 and 3BM22 munition,

Still.

In 2016 Jesus, f*ckin Chirst...

Apart that on base offset for buing in 2001 ATGM Spike polish industry had akcess to modern sabot's and "long rods" form Israel.

So on base israeli CL3579 MK.II was made polish "Pronit" round:

Prxa47N.jpg

 

 

It was made circa 1400 rounds when was discover on tests that 1/5 rods from IMI   have factory faliture and have smaller penetration in cold winter conditions.

So army stop buing Pronit.

Apart this polish industry had offer "new" rondu whit french rod:

tnocgIs.png

More od less polish army don;t bou this APFSDS too, so in circa 2016 polish army is still usinig 3BM15 and 3BM22. Greate...

 

 

------------------------------

In case 120mm ammo polish industry had developed whole family:

1lyWbFZ.jpg

 

In case 120mm APFSDS-T there is Pz.531  round as base "combat" APFSDS-T. Initialy it was polish copy of the German DM-33A1. But polish industry had it's own invention and made two pieces (segments) rod in penetrator. Yes - like in 3BM42 Mango...

 

Round:

0SyCJbX.jpg

 

and segmented penetrator:

 

 

HyJ9oZo.jpg

 

the bonus from sucht build was 10% better penetration then in DM-33A1 and ability to better overcome sloped  "convex" shape turrets roof like in T-72B or erly T-90S. But this round have not very good penetration 500-540mm RHA on 2000m.

Finnaly polish MoD consist that polish Leoprads-2 need a new APFSDS and industry developed "new" Pz.531 second generation round whit longer rod - taken from Plansee factory (France and Ostriech) - almoust the same as in DM43 round. This round is in production now. What is funny - polish MoD need again better round whit better abilities to overcome heavu ERA. Off the record - DM63 :) New round whit minimum 700mm RHA penetration abilitis will be buing from 2018.

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Eurostatory2016 - Nexter munition (IMHO mucht more interesting then intenrational onanism on 130mm Rheinmettal gun)

4d678c78b80a9.jpg

d92b0ee14076f.jpg

66adb2939b186.jpg

f664bac981633.jpg

Yes...datalink and programator in APFSDS-T Nexter F1B-NG:

e62e9e6a103cd.jpg

And it's not firs western APFSDS-T whit data link and programator:

Fv0uWoC.jpg

Why there is data-link/progamator in APFSDS-T round?
I have a theory:
Propably it is to somehow use a precursor that is "fired ahead" of the main rod.

700.jpg

So how the rod designs looks like here? The rod is made from two segments, the "precursor" and the main rod behind it. How they are connected? it might be some sort of polymer, glue that can be weakened by heat and the release precursor, and during flight rods heat up pretty nicely.

The precursor can also be relased based on a simple difference of speed between it and the main rod, and main rod can be slowed down by some sort of additional fins (aerodynamic breaks) released at specific point programmed by FCS. In such case precuros would initiate ERA and the main rod would have a clear way to main armor of the target.

How to cheat APS tough? Counting that precursor will be qualified by APS as threat and APS will be initiated, creating a time gap in APS reaction so it won't be able to counter the main rod? Possible yes, but then there is question, if APS will just not ignore the precursor, and this might happen, now of course there is a question how dangerous is precursor itself? For a MBT or vehicle with similiar levels of protection, for it's front it won't be dangerous in most cases, sides? If they do not have any addon armor, very possible. For lightweight platforms, yeah precursor also will be dangerous.

Of course these are only hypothesis, and we will see if other nations will also design APFSDS rounds with data link. Then we might get closer to the truth. Right now, treat it as food for thoughts.


And now French "new generation" OFL have progrmator. In case Abrams - datalink can be used for secure resons. In M1 gunner (not loader like in Leo-2) is setting type of ammo, so in theory there is posibilty that loader put for example APFSDS-T but gunner have still HEAT set up in FCS. So programator was some theory how to avoid sucht mistakes. But in Leclerc ammo? There are two barcode scaner in Leclerc Seriee XXI and bar code on ammo. So there is no posibility to "mistaken" loaded ammo.
So meybe my crazy theory about precursor in APFSDS could be real?

ps. USA had tested T-84 whit Knive = programator in new M829A4
Frencht had tested Knive ERA = pogramator   in new F1B-NG
Poland had tested Kinve ERA = "new" Leopard-2PL will have programator in Rh120mm gun...
Strange...

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From my article in Polish military press:

http://www.magnum-x.pl/artykul/tendencje-rozwojowe-przeciwpancernych-pociskow-podkalibrowych

 

Table whit APFSDS data:

D5jsKZ3.jpg

Value above is for @60 degree slopped plate in 2km distance.

 

 

There is one mistake above. For person who find it - full article (in Polish) :)

 

 

and value for DM53 from Polish industry (lol)

http://www.altair.com.pl/magazines/htmlissue?issue_id=827&ref=issue

page 5-6:

qGBezSX.jpg

 

So in theory  DM53 can achive 670 to 700mm RHA penetration acoding to manufacurer. Polish industry downgaraded this value in tabel in minus 40mm RHA to between 630 - 660mm RHA couse L50 barrel and 1710m/s muzzle.

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The Polish values are all very odd. Specifically the first table:

 

The DM13 penetrates 440 mm and the M827 (DM13 with DU instead of tungsten) penetrates 520 mm? That's 18% more, while US sources claim that DU offers 8 to 10% more penetration than tungsten. The German DM43 APFSDS penetrates 640 to 700 mm armor steel and the CHARM-3 APFSDS penetrates even 740 mm? It is also hard to believe that the M829A3 should penetrate 800 mm of steel, when the same forum page suggests that it has only a 625 mm long penetrator... then the M829A1 (with 680 mm long penetrator and higher muzzle velocity) would penetrate something like 880 mm of RHA.

 

Also, did the Polish magazine write that the penetration was downgraded to adjust for the different gun or was it downgraded because of other factors (different metholodogy for armor penetration, different penetration criteria)? 

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Hi Methos,

to be onest - In article I had used two russian sources :-) couse they have the same metodology:

 

lzzHrc2.png

F6ADXT9.png

Of course some of them was estimatous.

 

In term this polish military press - no hard data, just form context - couse diffrent gun.

 

btw: DU vs WHA it's old story,  in some sources there is 18% difrences between both material...

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Yes...datalink and programator in APFSDS-T Nexter F1B-NG:

e62e9e6a103cd.jpg

And it's not firs western APFSDS-T whit data link and programator:

 

I read a claim that the blue cable was a primer, but to me it seems like that would not evenly ignite the propellant.

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@SH_MM

 

About DU and WHA:

 

 

It is difficult to find information in the public domain about the effectiveness of DU and information that
makes an exact comparison with other materials is even more difficult to access. However, internal UK
government documents cite an improvement of about 15% in performance. A US government document
suggests that DU offered an average of a 52% increase in penetration above that of the tungsten alloys.

from:

David Cullen, Researcher, ICBUW

yes, poor sources couse to muchrt "green" ones...

 

So maybe better:

TenM7Mn.jpg

As We can see - for XM833 difrense is is between WHA and DU:

heavy single NATO target - 60% (!)

heavy tripple NATO target - 43% (!)

unkown incarease tragets: from 13% up to 38%

 

So yes, penetration difrences between DM13 and M827 may be so big...

 

 

More fresh study:

And form 1990:

aPhndDW.png

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More or less most study from 1980 -so no wery younger then DM13 and XM833 give us huge gap between DU and WHA penetration:

heavy single NATO target - 60% (!)

heavy tripple NATO target - 43% (!)

unkown incarease tragets: from 13% up to 38%

All for XM833 for DU and WHA core.

 

More fresh studies - from end of the 80s give us diffrence on 13-15% level.

 

BTW:

 

 

It is also hard to believe that the M829A3 should penetrate 800 mm of steel, when the same forum page suggests that it has only a 625 mm long penetrator...

It's only depend on one "factor" - real penetrator lenght in M829A3. My sugestion is that there is special "tip" or rather segment to overpas heavy ERA. In sucht case this segment should not take part in main armour penetration and this more then 800mm is BS. But...it's not so simple.

What if this "segemnt" will take a part in penetration process if there is no ERA? Then whole penetrator lenght is circa 800mm. And there is of course possibility that there is no any single sophisticated solution and we have just long and heavy rod. Again -at least 800mm long.

 

How big will be penetration of RHA monoblock by 800mm long rod whit V-drop circa 1500m/s? For 0. plate circa 800, for 60. plate - slighty more up to 880-900mm... Again - value "over 800mm RHA" is fully possible in M829A3 case.

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As We can see - for XM833 difrense is is between WHA and DU:

heavy single NATO target - 60% (!)

heavy tripple NATO target - 43% (!)

unkown incarease tragets: from 13% up to 38%

 

So yes, penetration difrences between DM13 and M827 may be so big...

I would not consider this document as valid for estimating the performance difference between DM13 and M827. The values for penetration are estimations from a document from 1980... at this time NATO didn't know how to manufacture monoblock tungsten penetrators. Instead the M735 and DM13 were used as reference to estimate the penetration, which both utilized steel-sheated tungsten penetrators instead of a monoblock design. These sheated penetrators were found to perform in general worse than monoblock penetrators (due to the larger parasitic weight of the steel sheating) and speficially worse against complex targets (such as spaced armor). Meanwhile the (X)M833 and (X)M829 are both utilizing monoblock penetrators.

The XM827 APFSDS was a 120 mm DM13 APFSDS with DU instead of tungsten penetrator, it still had a steel sheating and the same internal design as DM13. It would still be less efficient than either the M833 APFSDS or the M829.

 

While the other studies posted by you are certainly interesting, they are not very well suited for comparing the actual penetration of tungsten and DU penetrators. The US utilize the limit velocity and striking velocity for the comparisons; this however is not valid for real tank ammunition for the following reason: tungsten alloys tend to have a lower denisty than DU and according to W. Odermatt tungsten penetrators have a three times higher Young's modulus, requiring less sabot coverage/weight.

 

As you can see in the chart from "The development of a tungsten heavy alloy that fails by an adiabtic shear mechanism Phase I - SBIR", page 13, a L/D 20 scale penetrator out of DU will perforate some 96 mm of steel at a striking velocity of ~1,400 metres per second. The tungsten penetrator (same dimensions) will penetrate only some ~82 mm at the same velocity. However the tungsten alloy has a density of 17.6 g/cm³ instead of 18.6 g/cm³ - so it should reach a higher velocity when fired with the same gun and the same powder charge! In so far, we should not compare the penetration at the same impact velocity, but the penetration at the same impact energy. So we should compare the penetration value of DU at 1,400 metres per second to that of WHA 93% at ~1450 mps. This will again lead to some ~10% penetration difference.

 

The document "High velocity performance of a uranium alloy long rod penetrator" does show that the difference between DU and WHA at 1,400 metres per second impact velocity or more is equal or less than 10% - again this confirms the findings of L.S. Magness (with 8-10% difference in penetration between tungsten and DU for L/D 20 penetrators, the greater the L/D ratio the smaller the difference in penetration). The 97% tungsten content of the alloy was chosen to provide the same density (and thus essentially the same impact energy) as DU.

 

It's only depend on one "factor" - real penetrator lenght in M829A3. My sugestion is that there is special "tip" or rather segment to overpas heavy ERA. In sucht case this segment should not take part in main armour penetration and this more then 800mm is BS. But...it's not so simple.

What if this "segemnt" will take a part in penetration process if there is no ERA? Then whole penetrator lenght is circa 800mm. And there is of course possibility that there is no any single sophisticated solution and we have just long and heavy rod. Again -at least 800mm long.

 

How big will be penetration of RHA monoblock by 800mm long rod whit V-drop circa 1500m/s? For 0. plate circa 800, for 60. plate - slighty more up to 880-900mm... Again - value "over 800mm RHA" is fully possible in M829A3 case.

We don't know the real penetrator length of any recent APFSDS. It is all estimations. For me, the question is not "is it possible to have a penetrator of length X?", but rather "is ir reasonable?" In theory the M829A3 also might have only a 500 mm long penetrator... we cannot say until somebody actually post photos from a cut-through M829A3 projectile.

 

Against a 800 mm long penetrator however speaks the weight; this is why I don't consider it to be a reasonable option. At 25 mm diameter and 800 mm length, the volume of the new penetrator would be 52% larger than the volume of the M829A2 penetrator (for which we actually have data and cut-through projectiles). The M829A2's DU penetrator supposedly weighs 4.81 kilograms. This would mean that the M829A3's penetrator weighs 7.31 kg... leaving only 2.69 kg for sabot, tip, fins and tracer. The weight allocated in sabot, fins, tracer and tip of the M829A2 is 3.09 kilograms (with a smaller tip and a lot smaller sabot). The weight of the DM53's sabot, tip, fins and tracer is supposedly ~3.35 kg.

 

I don't think it is reasonable to assume that this is possible. I know that the M829A3 uses an improved composite sabot with lower density, but it is also a lot larger (~30%?) in terms of volume compared to the M829A2's sabot.

 

 

As for the rest of this discussion: I think that the M829A3 APFSDS follows the scheme from the patent. I can believe that it does penetrate some amount of armor, when there is no ERA; however the frontal segment has to be made of a lower density material - it cannot be DU, tungsten or tantalum without leaving too little weight for the sabot, fins, tracer and tip. The patent itself speaks of steel, which I consider reasonable to assume. How much armor can a 100 to 150 mm steel rod penetrate at 1,450 mps impact velocity? Something about 50-70 mm probably.

 

The M829A3 won't have a velocity of 1,500 metres per second at 2,000 m. The M829A2 supposedly looses 61 m/s per kilometre travel distance. The DM53 APFSDS looses 55 m/s per kilometre travel distance. The M829A3, being larger and heavier, should loose a slightly larger amount. With it's muzzle velocity of 1,555 m/s, it would loose only 27.5 m/s per kilometre to reach an impact velocity of 1,500 m/s.

 

 

In the end talking about penetration vs RHA is senseless, given that different penetrators reach different penetration against different types of special armor.

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The M829A3, being larger and heavier, should loose a slightly larger amount.

 

Not necessarily. I've been playing around with various LRPs and it turned out that an increase in size was offset by the increase in weight, giving the LRPs fairly similar deceleration values.

 

By the way, I'd love to see where you got the decel figures from since firing tables are restricted.

 

The total projectile weight for the M829A3 is 10 kg. M829A1 penetrator weight is 4.6 kg with a projectile weight of 9 kg, according to Orbital ATK.

 

How much armor can a 100 to 150 mm steel rod penetrate at 1,450 mps impact velocity? Something about 50-70 mm probably.

 

65-85 mm, depending on type of steel used.

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Not necessarily. I've been playing around with various LRPs and it turned out that an increase in size was offset by the increase in weight, giving the LRPs fairly similar deceleration values.

 

By the way, I'd love to see where you got the decel figures from since firing tables are restricted.

They were used for advertisment in the past. Firing tables for older ammunition is available online btw.

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Question; has there ever been a tank gun that used both two-piece and unitary ammunition?

 

Because I don't see any reason that one could not.

One of the newer (?) Chinese tanks. Mech has told me exactly which one, but I've forgotten.

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One of the newer (?) Chinese tanks. Mech has told me exactly which one, but I've forgotten.

 

The ZPT98 on the later Type 99 models.

 

 

Wouldn't the 125mm guns be able to? Their 2 piece ammo seems like more of a loading convenience than a functional necessity.

 

Not sure about other designs, I read a report once that the Type-96A can't due to the fact it doesn't fit the autoloader, that was a pretty long time ago to be fair though.

 

And the 125mm L/60, while not really known what, if anything it will be fitted to yet, was shown with only very large unitary casings next to it when it was unveiled.

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Not sure about other designs, I read a report once that the Type-96A can't due to the fact it doesn't fit the autoloader, that was a pretty long time ago to be fair though.

 

And the 125mm L/60, while not really known what, if anything it will be fitted to yet, was shown with only very large unitary casings next to it when it was unveiled.

 

Ah sorry I meant the gun itself.

 

For example if you had a Leclerc style autoloader paired up with a 125mm gun, the two piece ammunition could be manufactured as a single long round.

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