Change gun loadout in campaigns

[CoolingThunder]

Hi,
I just got the game, and I was wondering how to change ammo types on guns. I always aim for the engines or the wings, but when I open fire with the hurricane, it takes ages before it goes down. I feel like my guns don't have the right ammo type. I see parts flying off, but never flames or something like that. I remember from il-2 1946, that bombers always ripped up after a couple of salvos. I have to turn on unlimited ammo before 1 goes down. I have the idea to be shooting with a BB-gun. Or maybe it's because I'm just a big noob lol