Thread: Russian Armed Forces News & Discussion thread

  1. #2701
    Member fmaster's Avatar
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    Thanks for your explanation. However I was curious because Russian two-piece APFSDS rounds are inherently inferior to western single-piece counterparts due to their limitation of penetrator length which cannot be elongated more than the point where the penetrator meets the propellant. Then how could they improve their penetration to more than M829A3, the most modern US DU APFSDS which is said to have 700~800mm penetration, by just tweaking the sabot?

  2. #2702
    Senior Member Hyde's Avatar
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    Quote Originally Posted by fmaster View Post
    Really? That's some great penetration for a 125mm separated APFSDS. How could have they achieved such penetration without using a single-piece ammo?
    Just a hint, whether the ammo is in two pieces or in one piece doesn't make any performance difference.

    Quote Originally Posted by fmaster View Post
    Thanks for your explanation. However I was curious because Russian two-piece APFSDS rounds are inherently inferior to western single-piece counterparts due to their limitation of penetrator length which cannot be elongated more than the point where the penetrator meets the propellant.
    That's simply wrong.
    I don't know where you heard that fairytale, but it's wrong. The problem was rather in the limitation due to the lenght of the rounds the autoloader could accept.

    Here's a chart I found, it may not be 100% accurate, but it's enough to give one an idea about armor and armor-penetration performance.
    http://i.imgur.com/JWwdj.jpg
    Last edited by Hyde; 04-15-2012 at 01:09 PM.

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    Quote Originally Posted by fmaster View Post
    However I was curious because Russian two-piece APFSDS rounds are inherently inferior to western single-piece counterparts due to their limitation of penetrator length which cannot be elongated more than the point where the penetrator meets the propellant.
    Nothing to do with two piece or one piece , the older autoloader of T-72/T-90 tanks could not fire newer longer rounds , the modified loader of T-90MS can fire those and the Russian T-90A can do as well , Although modification can be done on existing T-90 autoloader to fire longer rounds. ( L=740 mm )

    Atleast the T-90S Bhishma cant fire the newer rounds due to limits imposed by its older autoloader

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    Here are some more technical details on 3BM42 rounds from a RFI floated by Indian MOD , they are ordering 66,000 3BM42 and 25,000 for Invar . The 3BM42 goes by designation AMK 339 by MOD

    http://www.ciidefence.com/pdf/RFI/RF...FSAPDS-AMN.pdf

    Caliber. The ammunition should be capable of being fired from 125 mm Smooth Bore Tank Gun of T-90 and T-72 tks.

    Shelf Life Not less than 15 (fifteen) years under Indian Tropical Conditions. Specification with regard to explosives fillings with test procedures to evaluate the shelf life be made available to DGQA (Indian QA Agency). Literature substantiating the claim that explosive fillings would give stipulated shelf life need to be made available.

    Technical Characteristics
    4. The major technical characteristics are as under:-
    (a) Round Designation of Mark - 3BbM17
    (b) Projectile Designation or Mark- 3bM-42
    (c) Mass of Shell or Shot (kg) - 7.05 kg
    (d) Mass of Round (kg) - 20.4 kg
    (e) Primer - GUV-7
    (f) Designation of SCC - 4>K 63
    (g) Increment Propelling charge - 9.50 kg
    (h) Muzzle Velocity (m/s) - 1700
    (j) Effective Range (M) - Not less than 2700
    (k) Consistency group of Rds - HSD & VSD ≤ 0.35 mil
    (l) Tracer - 3YPZM
    (m) Armour Piercing Characteristic. The depth of perforation (piercing) in mm.
    -
    Prospective vendors to state details.
    (n) Nominal Pressure - 440 M Pa
    (o) Maximum Pressure - 530 M Pa

  5. #2705
    Member fmaster's Avatar
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    Quote Originally Posted by Hyde View Post
    Just a hint, whether the ammo is in two pieces or in one piece doesn't make any performance difference.
    It seems that I was misinformed at some point around the autoloader. Still, I can't understand its penetration as the penetrator still appears to be kinda shorter than M829A3(800?mm vs 740?mm). Or are they using different methods to display penetration capabilities?

  6. #2706
    Senior Member Hyde's Avatar
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    Just as with the number of pieces, you assume the wrong thing, the absolute lenght isn't proportional to the performance. Not saying it doesn't have an effect, it obviously does, but you can not directly deduce the penetration capabilites from the lenght of the sabot alone, the gun and propellant also play a part, and are which gives the round the energy in the first place. If it was the other way around, a "western" round which is shorter achieving the same penetration as a Russian round which is longer, you would take it for granted and attribute it to some imaginary superiority and sophistication in "Western" engineering.

    If the round in question is longer and requires the new autoloader and is supposed to be used by T-90A or T-90MS and above, maybe the penetration figures were achieved using another gun, namely the newest 2A46M-5 or 2A82.

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    Quote Originally Posted by fmaster View Post
    It seems that I was misinformed at some point around the autoloader. Still, I can't understand its penetration as the penetrator still appears to be kinda shorter than M829A3(800?mm vs 740?mm). Or are they using different methods to display penetration capabilities?
    Penetration is a function of materials used, length to width ratio of the penetrator, construction of the round (how much energy is lost on the sabot for example), and the total kinetic energy of the round. Increasing penetration is not as simple as making the round longer. And anyway, the new upgraded T-90 autoloaders can accept rounds of up to 750mm long I think (thats not including the propellant charge).

  8. #2708
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    I'm not saying that Russian technology is primitive. I'm a rather Russian weaponry admirer. I just thought that Russia might be quite more advanced in such areas like material engineering/metallurgy than the United States if they could achieve same penetration with some 60mm shorter penetrator as the lengthening the penetrator without breaking the balance of overall ballistic performance is the most critical factor for the penetration anyway, and Russian 125mm guns like 2A46M-5 has somewhat less chamber pressure compared to western Rheinmetall 120mm(at least I heard so. If not, please enlighten me).

    Regardless, thank you all for the infomations.

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    Quote Originally Posted by fmaster View Post
    I'm not saying that Russian technology is primitive.
    Nope, you were saying that, because you've confused penetration ability with the penetrator length, while there's no direct dependency. There's a correlation, but that's it. There are many other variables in the equation, such as a mass of the sabot, powder charge, type of powder, all of which would determine a chamber pressure and thus (if you factor in the overall mass of the projectile, both sabot and penetrator) a muzzle velocity, etc.

    Quote Originally Posted by fmaster View Post
    and Russian 125mm guns like 2A46M-5 has somewhat less chamber pressure compared to western Rheinmetall 120mm(at least I heard so. If not, please enlighten me).
    Aren't you answering your own question here? Lower chamber pressure would probably require a longer penetrator to achieve the same ability.

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    Quote Originally Posted by fmaster View Post
    I'm not saying that Russian technology is primitive. I'm a rather Russian weaponry admirer. I just thought that Russia might be quite more advanced in such areas like material engineering/metallurgy than the United States if they could achieve same penetration with some 60mm shorter penetrator as the lengthening the penetrator without breaking the balance of overall ballistic performance is the most critical factor for the penetration anyway, and Russian 125mm guns like 2A46M-5 has somewhat less chamber pressure compared to western Rheinmetall 120mm(at least I heard so. If not, please enlighten me).

    Regardless, thank you all for the infomations.
    The initial 2A46 gun peak pressure of 5100bar (on par with the M256 L44 gun of the M1A1), the 2A46M-1 and later guns have peak pressure up to 6500bar. This gun is in use since 1981 and on all the modern Russian tanks. So I'm not sure where you get the lower peak pressure idea from.

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    Quote Originally Posted by void View Post
    The initial 2A46 gun peak pressure of 5100bar (on par with the M256 L44 gun of the M1A1), the 2A46M-1 and later guns have peak pressure up to 6500bar. This gun is in use since 1981 and on all the modern Russian tanks. So I'm not sure where you get the lower peak pressure idea from.
    Aha, that'd mean that I'm wrong here too. I was under impression that it's somewhere around 5500-5700 bar.

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    Quote Originally Posted by Khathi View Post
    Aha, that'd mean that I'm wrong here too. I was under impression that it's somewhere around 5500-5700 bar.
    I point you to Vasiliy Fofanov's page on Russian armour, which is a fairly good source on this stuff on the internet (although a little outdated now):
    http://fofanov.armor.kiev.ua/

  13. #2713
    Senior Member Hyde's Avatar
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    Quote Originally Posted by fmaster View Post
    I'm not saying that Russian technology is primitive.
    I'm not saying that you are saying that, I am just saying that the opposite thought ("Western" or "Israeli" being regarded and accepted as superior by default, without question, and the on-par-esness or superiority of Russian designs being doubtet and questioned by default) is engrained into our heads by our surroundings, and that that is the source for your doubts and questions. Always just imagine everything you are confronted with as if it was the other way around, and see how you would feel and what you would think then.

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    Quote Originally Posted by void View Post
    And anyway, the new upgraded T-90 autoloaders can accept rounds of up to 750mm long I think (thats not including the propellant charge).
    Upgraded as in on MS? Or are they being upgraded for the in service T-90A's?

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    IIRC, MO stated their intent to bring up all T-72 and T-90 to at least the T-90A standard (which can use longer APFSDS). To this end they might end up simply ordering the turret of T-90MS into production, and then put it onto older chassis, which will also bring a new FCS and optics to them. But I'm now sure how well would it sit economically, not to mention whether it would actually fit without a redesign. OTOH, the current plan for the armor force it to go on with the upgrading the current fleet, and this is one of the most logical steps in this direction.

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