It just should not happen, a 30mm should knock the wing right off.
Why is it x2 20mm can do it, but a nice solid 30mm is like a kiss to your enemy's plane?
Was it not rare to make it home in ww2 in a fighter aircraft after being hit by a 30mm? (i have seen one picture of i think a hurr with its tail section split, dunno if that should count, no fuel.)
I would think a 30mm to a wing filled with fuel & ammo, also (a high probability of being under + or negative G load!) would snap most fighters wings clean off.