I agree with Herohog, I would have expected him to get more time. I'm kinda surprised they didn't throw the book at him, as the ATF get's so few NFA prosecutions it seems like they always try to make examples of the idiots that get caught.
I say that while 100% agreeing that the law is BS. There's a lot of BS laws on the books that we all still (supposedly) follow. I can be simultaneously surprised the court gave him that sentence and dismayed that it was a crime at all.
On the bright side, at least he wasn't trafficking in people, and helping bring in an underclass that rich folks can exploit for cheap labor while avoiding tax laws. Oh, wait, that's OK now. My bad.