this could be another of those "let's change history a bit" points IMHO.

303s didn't deliver the expected punch simply because a)they're small calibre and b)they weren't harmonised at a close distance, but used the (in)famous Dowding Spread, which was meant to create a "cloud" of bullets at 400 yards to defeat aiming inaccuracy and bring bombers down, but in reality it was simply a stupid idea, which only caused German bombers to come back with hundreds of holes in their fuselages.

The changes made by the 1st Sqn made the difference in fighting, with harmonisation to one point taken down to 250 yards, delivering a concentrated punch in one specific point by 8 machine guns.

The idea is to aim for the pilots fellas, you'll save a lot of ammo and shoot down a lot more enemies.. sad, but hey, war is hell!