It was a whole lot of motivated speculation about how some people were thinking hundreds of years ago and how they would interpret contemporary weapons. It is indistinguishable from a reddit post with fancier words. Scalia would have been happy to hear you think it's a fantastic piece of legal scholarship, though - it was his job to dress up his opinions in that way. I quite enjoyed this account of it: https://www.fivefourpod.com/episodes/dc-v-heller/