Regarding your answer in self defense vs civil disobedience. You asked if people were really prepared to stand alone against an armed military force and refuse to turn over their hunting rifle. If the answer to your question was yes and people would choose to make a stand against a tyrannical government (as I am sure many people will do) the original question remains. Is it self defense? I don’t own a gun but I know many Christians who are gun owners.
I’m not a lawyer but I think the refusal to surrender a weapon in violation of the laws of a legally constituted government would be an act of civil disobedience, not self defense. In the original question, the military force would not be coming to your home to inflict bodily harm, but to confiscate your weapon. Obeying them would not put you in any immediate danger so there would be no need to defend yourself.