The japanese 30mm cannons used to be god tier good, with 920ms rounds. But they nerfed them a year or two ago, in return gave them better armour pen for CAS use. Hence why you now see them being used as CAS planes.
I was suprised how many of them started showing up in GRB right after spookston posted his video on it lol. They were pretty much free kills for anyone flying CAP

