looks more like a Artillery piece then a tank gun
maybe but the mounting is a Arty system. If it was Turret mounted... Seems a bit long but Okay
There's a fume extractor, suggesting use in confined spaces. I think the towed mounting we see is just for display purposes, i.e.: they're just showing off the gun, not the actual turret or mounting.
There's a suggestion that the gun could be for a next gen MBT or tank destroyer. The indirect fire mode with 40km range would be useful for firing sensor fuzed munitions or top attack anti tank missiles.
Sounds like the gun could be used on a universal platform that will branch into MBT, artillery, etc, variants.
Looks kinda like the big beasty they have on the 052Ds, a smaller cousin perhaps?