[Pyrres]

First of all check how many bullets do actually hit. Then think how small and low powered the bullet is without HE shell. Plus the WW2 .303 bullets were not as effective as modern ones, and as the bullets and guns themself might not be perfecly manufactured the bullets made a sort of shotgun effect, and everyone knows that shotgun is not great gun for sniping. After that think how small the target you can hit is when firing from dead 6. Also as it has been said there is not much to damage exept the skin in the rear part of the plane.

What I´m trying to say is that you shoot a 2second burst, maybe 25% of the bullets hit the target. The bullets might or might not hit anything vital or just fly straigth throught the plane. After most of the bullets have been wasted missing compitely or on tearing just the skin of the plane and not the structure itself will land in the armored parts or parts that might not be vital for flying the plane. Your radio, pneumatics, hydraulics, gunsight, engine parts, parts of control surfaces, lots of internal damage, pilot wounded etc might be missing but the plane is still flying. Think how many times have you been damaged and you have not even noticed you have been hit. This happened also in IRL as many pilots flew home just to notice that a bullet has missed their head just a few centimeters. So even if you can not see the damage does not mean that it is not there. The plane might fly for minutes, or fly for hours but still be damaged beyond repair or crash at landing or under high G load because of the damage.

EDIT: And Fredfetish: Basicly just try to hit something important and the planes start to fall. I understand what you are thinking and going after and you are mainly right, but you don´t take all the effects and things to considerations

EDIT2 Oh and this game is now much much more realistic as the planes do not always disinigrate or blow up but die slowly. Of course I have been able to blow quite many HE111´s with hits in the fueltanks but mainly I move over to the next target after I see smoke or pilot killed.