Law School Text on 2A and Firearms Law
Pricey, of course, but there are some free podcasts covering chapters from the text at the link.
"To spit on your hands and lower the pike; to stand fast over the body of Leonidas the King; to be rear guard at Kunu-Ri; to stand and be still to the Birkenhead Drill; these are not rational acts. They are often merely necessary." Pournelle