putting a smaller he shell is a sabot will not decrease the size that much
No, what I mean is that a HE shell has a specific length to width ratio so it does not work to just shorten rounds.... you have to make them narrower too,but if you make them narrower and shorter they wont go down a 152mm calibre barrel.
A short stubby propellent case with a fraction of the propellent of the APFSDS rounds and a shorter narrower HE round.. say 70-80mm calibre with a sabot to fill the barrel width will take up rather less room... you could make them5 times shorter than the full sized 152mm rounds so for each autoloader position you could store 5 rounds.
i dough a 1/5 load of HE will have sufficient power to destroy a fortified building in 1 hit like a 152mm HE round would I heard that there was a case in Afganistan where the terrorists had fortified some oil refinery or something and 122mm shells were not enough and they ended up using 240mm Tyulpan mortars.
If the target is a heavy fortified stone or concrete building then standard 152mm HE rounds can be used, but for a sniper or MG position in one room of a building you could fire an 80mm calibre HE shell with say 6-10kgs of HE and a delay fuse so it penetrates the position before detonating.
As for AA platforms the Tunguska and Pantsir are light platforms and it seems a bit wasteful to mount a light AD armament on a heavy vehicle I would expect the Armata AD to have heavier armament than the Pantsir like 2x 30mm gast guns + 2x 57mm + 8 short range SAMs and maby some ATGMs for self defense.
Tunguska is 34 tons... it is hardly light. The AD Armata will likely have Pantsir-SM with 40km range SAMs... it might have 12 or perhaps 16 missiles but I think the vehicle would be big enough to also carry a 57mm cannon instead of 30mm cannon in the anti aircraft role. They might separate out the missiles and cannon due to the size of the 57mm gun. TOR will likely remain a missile only system though the armata version might have no turret and a large superstructure with fixed AESA modules and 32 or more ready to launch missiles in vertical tubes. The standard TOR in the latest model has 16 missiles in the turret ready to fire so I would expect the Armata version to carry more.... possibly in a towed trailer with vertical launch missiles ready to fire.
The use of Tor missiles in Armata (Kurganets, Bumerang and BMD-4M) platforms is a lot less likely since they have lower range and performance. The Tor missiles likely are not modern enough for the new platforms, despite to be a very capable system today is unlikely to remain 50 years from now (the approximate life of the new units of the new platforms). The SA-15 Tor systems will very likely remain in the units with T-90, BMP-3 and older platform weapons.
The new TOR missiles are smaller and are carried in larger numbers on the original platfom (16 instead of
. Range is also increased to about 15km.
The TOR missiles use sophisticated electronics and sensors on the platform but are cheap simple command guided missiles of very high accuracy.
Using fixed phased array antennas for search and tracking a large platform like Armata could carry large numbers of missiles which don't need to be pointed in the direction of the target before launch... one vehicle could cover 360 degrees continuously and rapidly launch missiles to defeat all sorts of targets.
The TOR is intended to engage incoming munitions as well as enemy aircraft so its range is not an issue at all... larger SAMs can engage enemy aircraft before they launch, while TOR can deal with any munitions that have been launched very very effectively.
The second option most likely to be mounted in the Armata, Kurganets, Bumerang and BMD-4M platforms would be the S-350. It would make a good combination with the Pantsir mounted on the same platforms.
S-350 is an Air Force/Navy/air defence force system. the Russian Army has BUK-M3 with 6 heavy long range missiles per vehicle and S-300V4 above that.