Why would anyone feel that a warning shot is necessary for someone that smashes down your door while uttering threats?
Any competent person that trains people to use firearms in self-defense makes one thing very clear.............warning shots are not permitted for the following reasons:
You might need the round you fired in the ensuing fight.
At night, muzzle flash inhibits night vision.
You are responsible for every round, and a warning shot may go where you did not intend.
And, most importantly, if you REALLY need to shoot to defend yourself, there is no time for a warning shot. If you need to shoot to save life, shoot centre mass......if you do not need to shoot to preserve life....DON'T SHOOT.