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I am getting conflicting views on this.

 

Developed to be able to defeat the K5 ERA on Russian tanks. No doubt it employs a few methods to do this.

 

One thing is not clear to me though. That is the presence of an break away or arrow tip on the M829A2.

 

The KEW-A3 clearly has it.

 

http://i.imgur.com/TxRK8Lp.png

 

CHARM-3 has it

 

http://www.bandepleteduranium.org/en/images/346_a379.jpg

 

The m829A2 I am not so sure.

 

 

http://www.inetres.com/gp/military/cv/weapon/120mm/120mm_M829A2_APFSDS-T_T.jpg

 

http://photobucket.com/gallery/user/APFSDS/media/cGF0aDovNDAzMzA0NS1maWctMS1sYXJnZV96cHM1NzM3M2ExZi5naWY=/?ref=

 

Doesn't appear in this computer model

 

http://www.steelbeasts.com/sbwiki/images/thumb/f/fd/M829A2.jpg/800px-M829A2.jpg

 

 

Does anyone know for sure?

 

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M829A2 uses special tip construction that drastically reduces chance of detonation of 4S22 K5 blocks. Won't work against 4S23 Relict trough.

 

Are you sure? The stepped tip on the M829A2 isn't special or new. M111 "Hetz" had a stepped tip as well, although it was made from cylinders and not homogeneous with the rest of the rod. Given that M111 was widely used in the USSR as a surrogate for Western APFSDS, they surely would have found it unacceptable if Kontakt-5 failed to detonate from M111.

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Are you sure? The stepped tip on the M829A2 isn't special or new. M111 "Hetz" had a stepped tip as well, although it was made from cylinders and not homogeneous with the rest of the rod. Given that M111 was widely used in the USSR as a surrogate for Western APFSDS, they surely would have found it unacceptable if Kontakt-5 failed to detonate from M111.

It wasn't exactly steps, but steady increase in diameter of penetrating cap.

v_Mb7HSSkP4.jpg

Something close to that.

Well, at least as far as we know. US late longrods are usually pretty obscure to be totally sure in anything.

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  • KEW: M829 with tungsten penetrator
  • KEW-A1: licence-made 120 mm DM43
  • KEW-A2: M829A2 with tungsten penetrator
  • KEW-A3: M829A2 with tungsten penetrator and SCBD propellant

The cut-through photograph in the KEW-A2 and KEW-A3 flyers from General Dynamics has also been used for the M829A2, it actually seems to show a M829A2 round. It honestly seems that the dark part is a windshield, not an anti-ERA tip. My understanding is that the M829A2 was a brute-force attempt to defeat Kontakt-5, which was rushed into service as fast as possible. It features some design improvements against Kontakt-5 (i.e. new DU alloy to reduce the likelihood of shattering), but mostly seems to be focused on increasing the overall penetration (higher muzzle velocity, slightly improved penetrator geometry) and thus making sure that there still is enough punch left after the Kontakt-5 ERA to defeat the main armour.

 

The M829A3 seems to be the proper anti-ERA design making use of the improved alloy, but also features more optimized geometry (thicker penetrator to make shattering and bending harder) and an anti-ERA tip.

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I am not sold it is just part of the windshield. In the KEW-A3 picture the leading section ahead of the stepped tip is much darker then the silver background which appears to be the main part of the windshield, It also has a great deal more relief, and shadow. You can also see that the conical piece has more relief and is solid. Maybe it is a windshield design, but on a round that was designed to defeat ERA having a design element that appears similar to other solutions known about at the time, makes me think that this advanced windshield design theory needs more of an explanation then an anti era element.

 

"My understanding is that the M829A2 was a brute-force attempt to defeat Kontakt-5,'"

 

Why is this your understanding? It seems to me that if K5 works as advertised adding another 40-60mm of penetration from a velocity increase will have little effect. From what we know about K5 ERA a higher velocity makes initiation more likely.

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Why is this your understanding? It seems to me that if K5 works as advertised adding another 40-60mm of penetration from a velocity increase will have little effect. From what we know about K5 ERA a higher velocity makes initiation more likely.

 

Kontakt-5 doesn't stop an APFSDS round, but only reduces its penetration. We know from Russian performance estimates and NATO testing (mostly reports from Jane's Defence Weekly and similar magazines) that the M829A1 was incapable of defeating at least the T-72B and T-80U with Kontakt-5. According to Nii Stali, Kontakt-5 improves the armour protectiton of a T-72B/T-90 by 20% (or rather: it reduces the penetration of the APFSDS by 20%).

 

Based on the estimated performance of the M829A1 (somewhere around 600-650 mm at combat ranges against sloped armour) and the estimated armour protection of previously mentioned tanks, adding just a few centimetres in penetration might be enough to defeat the base armour, even if Kontakt-5 keeps reducing the overall penetration by 20%. The T-72B's turret for example is often estiimated to provide somewhere between 500 and 600 mm protection by the more reliable sources (its armour array is known and the thickness of the layers is relatively well documented), it could survive an impact of the M829A1 APFSDS only thanks the protection provided by Kontakt-5 ERA. The added raw penetration of the M829A2 together with its (slightly) reduced vulnerability to ERA (new DU alloy containing Vanadium) could make a change from "not being able to penetrate a T-72B with Kontakt-5 at most places at all but the shortest combat ranges" to "being able to penetrate a T-72B with Kontakt-5 at European combat ranges at most places of its turret and hull armour".

 

 

I don't think that the velocity will change anything regarding the performance of Kontakt-5 ERA; the impact velocity is more relevant for the binary question: "Will the ERA fuse or not?" The Soviet ammunition had a much higher velocity and still could defeat Kontakt-5 with special tip constructions.

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Why is this your understanding? It seems to me that if K5 works as advertised adding another 40-60mm of penetration from a velocity increase will have little effect. From what we know about K5 ERA a higher velocity makes initiation more likely.

 

Kontakt-5 doesn't stop an APFSDS round, but only reduces its penetration. We know from Russian performance estimates and NATO testing (mostly reports from Jane's Defence Weekly and similar magazines) that the M829A1 was incapable of defeating at least the T-72B and T-80U with Kontakt-5. According to Nii Stali, Kontakt-5 improves the armour protectiton of a T-72B/T-90 by 20% (or rather: it reduces the penetration of the APFSDS by 20%).

 

Based on the estimated performance of the M829A1 (somewhere around 600-650 mm at combat ranges against sloped armour) and the estimated armour protection of previously mentioned tanks, adding just a few centimetres in penetration might be enough to defeat the base armour, even if Kontakt-5 keeps reducing the overall penetration by 20%. The T-72B's turret for example is often estiimated to provide somewhere between 500 and 600 mm protection by the more reliable sources (its armour array is known and the thickness of the layers is relatively well documented), it could survive an impact of the M829A1 APFSDS only thanks the protection provided by Kontakt-5 ERA. The added raw penetration of the M829A2 together with its (slightly) reduced vulnerability to ERA (new DU alloy containing Vanadium) could make a change from "not being able to penetrate a T-72B with Kontakt-5 at most places at all but the shortest combat ranges" to "being able to penetrate a T-72B with Kontakt-5 at European combat ranges at most places of its turret and hull armour".

 

 

I don't think that the velocity will change anything regarding the performance of Kontakt-5 ERA; the impact velocity is more relevant for the binary question: "Will the ERA fuse or not?" The Soviet ammunition had a much higher velocity and still could defeat Kontakt-5 with special tip constructions.

 

 

 

"Russian performance estimates and NATO testing (mostly reports from Jane's Defence Weekly and similar magazines) that the M829A1 was incapable of defeating at least the T-72B and T-80U with Kontakt-5."

 

I have never seen the M829A1 mentioned. Only the M829 in the original header to the article. If you have access to this article in entirety I would be interested in the details.

 

"According to Nii Stali, Kontakt-5 improves the armour protectiton of a T-72B/T-90 by 20% (or rather: it reduces the penetration of the APFSDS by 20%)."

 

That is almost certainly the high end. The USSR didn't have long thin monoblock DU APFSDS to test K5 against. Also from information I have seen initiation of the explosives wasn't reliable against thicker rods traveling at velocities lower then 1500m/s, and further not reliable against rods with diameters less the 45mm IIRC.

 

IMHO both the M829A1 and K5 T-72B and T-80U were at the edges of each others performance envelope. There is little doubt that defense industry in the USA was more then happy to lobby for a new round to provide "overmatch" against Russia armor.

 

"I don't think that the velocity will change anything regarding the performance of Kontakt-5 ERA; the impact velocity is more relevant for the binary question: "Will the ERA fuse or not?" The Soviet ammunition had a much higher velocity and still could defeat Kontakt-5 with special tip constructions."

 

I agree.

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No, that "special tip" is just a denal wad. It's there to increase performance on heavily sloped armour, not to prevent detonation of ERA.

 

That seems very reasonable looking at it now.

 

Why add that though? Is the stepped tip not designed for heavily sloped armor, or do the two elements work better together?

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No, that "special tip" is just a denal wad. It's there to increase performance on heavily sloped armour, not to prevent detonation of ERA.

That seems very reasonable looking at it now.

 

Why add that though? Is the stepped tip not designed for heavily sloped armor, or do the two elements work better together?

My guess is that there isn't any reason not to put one there, so they just did.

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