Thread by @LIM49Spartan

Let's discuss this captured BMD-4 walkthru posted on Ukraine Weapons Tracker:

https://twitter.com/UAWeapons/status/1520427996737327109

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As previously noted by UWT; it's previously unseen footage; the snow indicates it was videotaped perhaps in February or March.

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The BMD-4 is one of three vehicles in the Russian inventory that uses the "Bakhcha-U" Module (aka Turret); the other being the BMD-3 and BMP-3.

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"Bakhcha-U" integrates a 100mm 2A70 gun, a 30mm 2A72 autocannon, 7.62mm PKT coaxial machine gun, and the 9M117 Bastion Gun-Launched ATGM (through the 100mm gun) with a relatively modern fire control system.

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Ammunition loaded into the "Bakhcha-U" Combat Module is roughly:

100mm: 34 rounds in autoloader.
30mm: 500 ready rounds (245 HE, 255 AP)
ATGM: 4 rounds manually loaded.

While the autoloader is all electric, avoiding fire hazards from a hydraulic system....

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You can see just how unarmored the entire system is during the walkthrough.

There's no armor protection whatsoever for the exposed 100mm ready rounds, either from side hits, or from frontal hits -- the driver sits directly in front of the exposed carousel.

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Additionally the Gun-Launched ATGMs are stowed in the open; as is the 30mm ammo in open tubs.

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A set of quick and dirty estimates for each weapon system:

49 grams HE and 126 grams of propellant in each 30mm (HE) round:

12~kg HE, 63kg propellant for 30mm

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1.7 kg HE in each 100mm 3OF32 (HE) round and about 0.45 kg of prop. in each round (estimate based off 7.5 cm KWK 37 L/24 which had 0.37 kg prop):

57.8 kg HE, 15.3 kg propellant for 100mm

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9M117 Bastion is hard, but we can estimate based off it's total mass of 17.6 kg. Figure 70% of it is propellant or HE for the warhead; and we get 12.32 kg of energetics per missile.

49.28~ kg estimate of energetics for Gun Launched ATGM.

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Total Energetics:

69.8 kg High Explosives for Guns
78.3 kg Propellant for Guns
49.28 kg Energetics for ATGM
---------------------
197.38 kg (435~ pounds) Total

All of it stowed completely in the open like it's 1940!

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It can get worse - in the early version of the BMP-3 with the first version of the turret, an additional 18 x 100mm rounds were stowed in a reserve ammo rack under the three rear passenger seats.

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As you might guess, this much energetics stored with zero thought for protection causes...interesting things if the hull is penetrated, as shown by these photos of BMP-3 remains, where the hull completely...evaporated, basically.

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Russian AFVs up to about 1996 (the Chechen Wars) were designed with survivability after penetration as an afterthought; the idea being if the AFV had as much armor and firepower as possible on as small weight or volume as possible; it would have max. "combat potential"

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As we've all seen; this...hasn't worked out as well as they thought it would. Survivability is so bad, that entire vehicle crews are being incinerated after potentially survivable hits; because of Soviet designers' insistence of putting 100 lb sledgehammers into a 60 lb bag.

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On paper, this theory looks good; as shown by the comparison of the M1 Abrams and T-72 (which became the T-90); the T-72/90 is significantly smaller, carries a bigger gun (125mm vs 105mm) and has about the same armor (the original M1 was only about 50 tons combat weight).

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However, Abrams was able to be upgunned easily to 120mm, and was able to swallow more armor in various upgrades M1A1(HA) and M1A2, etc which raised combat weight to about 70~ tonnes; in addition to better inherent survivability due to bustle ammo compartment.

END THREAD.

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