If you run into it on sale, buy military surplus like Eric suggested or go to a gun show you buy it where you can get it cheap. By contrast some of the real hard core "protecting against the ebil guvmint types may have that much just in their trunk and may have more firearms in their car than this guy had total.
Contrary to popular belief if you live in the backwoods of some places in America it actually can be dangerous. Things like an AR are real good for coyote that are trying to get to your livestock. Kentucky, Tennessee , West Virginia, North Carolina, South Carolina, Western Maryland all have these things called bears. And they kinda like coming up to people's houses at night when pickings are slim back in the woods.
These dude may very well be a scumbag, and he kinda looks like he is. But it ain't cuz he's a weapons hoarder.