P-51C is perfectly effective with just four.
And in my experience (with far more games in these aircraft than you), firing HE at the tail is a great way to waste all your ammo, when you could instead kill their pilot or engine and move on.
Just yesterday I was firing from behind at a Spitfire Mk9, which was flying while missing an entire wing! :

Barely missed his pilot, but hit his engine and took it out before a friendly behind me destroyed his other wing. It took this much effort (and at least one of us sacrificing ALL their altitude) to kill a target that had ALREADY lost an entire wing.
Why is he flyable? Why isn’t he flatspinning? Why should I want lower gun damage, when clearly missing entire wings still leaves you perfectly capable of returning to base and being a threat again in… two or three minutes?
It’s half HE, half AP. According to you their tail should be falling off every time before the pilot or engine dies, but this is not the case.
Good, otherwise the Ki-61s would be way too low in BR. This plane does not belong down at 2.3 or 2.7. It must always be much higher.
What difference does it make, other than this P-51 flying around for a while with a burning wing? He only has those two fuel tanks, so they’re guaranteed to have a good amount of fuel in them. The fire won’t go out before the wing is completely damaged, and it will likely spread to the other tank.



