While I wait forever for itunes to figure out how to update my codex, it does appear that the update lists Karamazov using his orbital bombardments every turn, and psybolt ammo including to cover assault cannons and heavy bolters. So yes, Psymera's are only a few minutes or hours away (depending on how much I have to fight with this to update).
So yes, heavy bolter in the hull and turret with psybolt ammunition. Add in a storm bolter if you want to go crazy.