Originally Posted by Gerbil Maximus

The .303's are under powered. You can read many accounts from pilots that state giving german aircraft in the battle a 2-3 second burst and watching the aircraft disintegrate before their eyes. For larger aircraft of course more power was needed hence the introduction of the 20mm.
But everyone presumes that because the round is a .303 it wont do much damage, a single .303 wont do much thats true but were are talking huge volumes of rounds.
Lets do the maths }
8 guns
Each gun can fire 1,200 rpm (lightened breaches etc for aircraft use)
So thats 9,600rounds in 1 minute.
So if we divide 1,200 by 60 that gives us 20 rounds from 1 gun every second.
20x8=480 rounds from all guns in a 1 second period.
480x3=1440

A 3 second burst into an enemy aircraft unleashes 1,440 rounds into it.
The hurricane and spitfire both had around 16 seconds worth of fire.
Logically it speaks for itself.
Maybe the aircraft might not suffer structual failure (like a spit or hurricane would) but the vital parts would most likely be hit and pilot killed/wounded.