HSTV-L has an undeveloped ammo

  1. why is hstv-l has less pen then bulldog m41?

  2. I mean, on the website that the snails used to create this tank it says that it says penetration comparable to the M774 shell (372mm)
    High Survivability Test Vehicle - Lightweight (HSTV-L) - Tank Encyclopedia

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It’s because the XM885 (Delta 3) dart is probably modeled quite wrong at the moment. Though, I’d like for anyone from Gaijin to provide the current sources on it to prove otherwise.

As of the (slightly outdated, but then again XM885 hasn’t changed one single bit since introduction) APFSDS stat spreadsheet, the XM885 is modelled as a 26x270mm APFSDS round with a muzzle velocity of 1463 m/s. M464 (the bulldog apfsds round) has roughly the same velocity, but the dart is modelled as a 20.6x309mm round, which gives it improved penetration because of length.

We know from documents that the muzzle velocity is already incorrect for the gun used on the HSTV-L. It should be more around 1600 m/s. Not to mention the dimension of the dart make not a whole lot of sense. It’s really not consistent how Gaijin models some APFSDS, take for instance OFL 90 F1 APFSDS and XM885. Very similar weight and they are both modelled with the same subcaliber diameter, yet somehow the 90mm APFSDS is able to be 105mm longer than XM885. That kinda makes no sense, if we assume these rods are modelled as cylinders, that just exceeds its actual weight.

I’ve been trying to find more info on XM885 lately, but it’s really hard to find any. This is all I can really find, that is somewhat conclusive.

Cartridge case (from “The Eugene Stoner Tapes - Part 7: Large Caliber Cannons”):

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Cartridge case with dart:

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Dart with sabot:

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XM885 (100% it) dart on display (XM884 HEVT as well):

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Doing pixel measurements on the last image, with the game given diameter of 26mm, gives a length of 570+mm, which is completely absurd and not possible.

I measured around 375 pixels for length (I only included the length were the diameter is constant, so excluding tip) and 17 pixels for width. Trying to keep this ratio, together with a mass of m = 2.27 kg (mass according to docs) and density of 18600 (density used by WT for DU, which it is according to docs, in game it’s WA). Results are about a 19x420mm dart, which makes more sense considering it is a CTA round, which often use near the entire length of the case (case dimensions are 5.2x19" according to docs).

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Putting it through Lanz Odermatt gives 364.3mm@0° which matches M774 stats quite well as well as documents. However with corrected velocity for XM885 of 1646 m/s, penetration increases to 399.9mm@0°. Which matches the description of the page you linked.

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Sadly of course this is not enough evidence for Gaijin to fix XM885, however I hope it is able to at least prompt Gaijin to revisit the 75mm XM274. Becaues the current statistics are even more nonesense and most likely based on nothing. And I’d also still like to see XM884 for the gun, but that’s besides the point.

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Thats really cool information, thanks. But btw, why the snails dont wanna up penetration xm885? Cus if hstv-l been on 9.7 (like 4 years ago) its been okay, but on top tier that ammo cant penetrate t80 bvm and t72b3 in side and leo 2 in front.

Probably a mix of balance and lack of information. Balance is really up to Gaijin only sadly, there’s not much to say about that. I hope Gaijin will eventually at least try reestimate XM885, because again, the current stats are nonesense.

I would also fully accept the HSTV-L moving to 11.7, if XM885 got fixed (and maybe even with addition of XM884?).