Most planes will eat up 6-7 cannons before something is blown off, 30mm it's always a major part
4 hispano hits in most planes will kill you, esp if they are closely grouped, which they would be if they were all shot roughly at the same time near convergence.
reasons why hispanos are easier
1) much greater 'effective' range (except for grizz, most can't make a tater shot from more than 250 out).
2) much greater rate of fire
3) much flatter trajectory
4) one of the most powerful 20mm cannons in the game
5) someone who hasn't spent months practicing aim, can hit targets with it.
all around, the hispanos are amazing weapons.
