Colaborate work with Serhii
https://www.artstation.com/serg_r
Serhii has make base mesh for hull (with gun). I have made the high-poly usuing my own parts: tools. wheels. tracks etc.
This model of ASU-85 is available for sale:
https://www.cgtrader.com/3d-models/military/military-vehicle/asu-85-self-propelled-gun-high-poly

ASU-85/ZSU-23-4 Shilka wheels: https://www.cgtrader.com/3d-models/vehicle/vehicle-part/zsu-23-4-shilka-wheels-set

WW2 Soviet Tank Equipment: https://www.cgtrader.com/3d-models/vehicle/vehicle-part/ww2-soviet-tank-external-equipment-set