Ex-ATF Agent Doesn't Know Firearms

Color me surprised.

What’s missing from Heller is a comparison of guns at the time the Second Amendment was written and now. Had the Framers time-traveled to a contemporary gun store, they probably would have been astonished at just how lethal firearms would become. They might have even graced the Second Amendment with an additional clause that placed limits on the madness.
But they didn’t. Neither did the Heller justices, who completely ignored the stark contrast between then and now. One wishes that a law clerk looked up Section 921(a)(16) of the Gun Control Act of 1968, which exempts weapons with antique ignition systems or that do not use fixed ammunition – in other words, the guns of the Framer’s era – from the definition of “firearm.”

For someone who was supposed to enforce firearms law he doesn't seem to know firearms or their history all that well. After all, the Cookson repeater (a flint-lock lever action), the Belton Flintlock, and Girondoni Air rifle were all in existence at the time.
Also - using the Gun Control Act of 1968 to justify his interpretation of the constitution is pretty stupid, given that the GCA isn't a part of the Constitution and post dates it by over 150 years.