Perhaps you don't understand "immunity from civil suit"
But the courts are supposed to throw out such suits with prejudice, if a self-defense claim is substantiated.
And if a BG, or his survivors depending on how the SD case initiated, file suits, there is always the threat of countersuits for the mental anguish, legal hassles, etc caused by the BG breaking in, attacking etc. If the BG's actions warranted a finding of self-defense, I'd think I'd have better odds on the countersuit.
Meanwhile, my point remains - hunting guns aren't always practical or even possible.
If I decide to compete with my M1 Garand, does that mean that I should use it as my first choice for HD since it's a weapon I'd regularly use for a recognized sporting purpose? If so, how is an 8-shot semiauto .30-06 less scary than a 6-shot pump action 12ga?
I could always have an attorney consult a Massad Ayoob type self-defense expert witness, so he'd know to point out things such as: What do local police departments carry as squad car weapons? (12ga pump with short barrel and extended mag, or AR-15 variant, or Mini-14) OR Why does the defendant have an AR-15? (Defendant bought it so he could practice between military deployments, and later so he could practice prior to deployment as a defense contractor; defendant prefers the AR and the short barreled pump because he received military training on them and is most proficient in their uses, as far as long guns go) etc.
Again, my biggest worry isn't the hardware, it's making sure I have exhausted reasonable options prior to pulling a trigger with whatever weapon I use, and in making sure that my rationale is made clear, after consultation with and in the presence of my attorney. (Theoretically; haven't had to use a weapon for SD, and hope I never have to)