Ooh wait we already had ATOM 40mm programmable airburst grenades.
Even there is armour piercing 40mm grenade.
The ATOM launcher system is very compact.
What would happen if the T929had this 40mm smart ammo system instead of 20mm auto cannon or with it?
For armour penetration the helicopter could just use UMTAS and CIRIT.
From a helicopter , Against hidden troops/terrorists ATOM ammunition would be more effective than 20mm HE or CIRIT.
Using an auto cannon armour piercing sabots sounds old school in the 2022.
BTW German Eurocopter Tigers don't have autocannon.
AH1G being loaded 300 40mm grenades.
AH1G firing twin grenade launchers. I adore old army documentary. Skip to 2:55
This video is real helicopter gun porn !
Here are the airburst and shaped charged 40mm grenades