While the details on the panthers and other historical topics were pretty good, the defining of the second amendment was not. The author proved with so much of the article that he is smart enough to get details thoroughly correct, and with other parts wants reasonably knowledgeable people to think he's either inept, lazy, dishonest or stupid, essentially crushing any credibility level he could have had with people who understand these things.
What's worse is that he used his own ineptitude as a way to go after the NRA, when there are dozens of better ways to slander the NRA if you wish to. His definitions of the second amendment and militias struck me as utterly pathetic. The article was indeed otherwise good. I only wish the author would step up his integrity level when it comes to facts he's uncomfortable with.