When you let harebrained federal officials make the laws.
David Olofson, a National Guard drill instructor, is serving a 30-month prison term because his semi-automatic rifle malfunctioned and shot three rounds after he let a student shoot it during a lesson in proper gun use.
Keep in mind Mr. Olofson never harmed or even threatened anyone with his rifle. The ATF is simply railroading him over a technicality in a stupid law because it can. Intent doesn't matter.
But remember, we're a free country.
And for the record, yes, of course machine guns should be legal.
(Thanks to Dan.)