Well, I am going by Matt Bracken's "Enemies Foreign and Domestic." In one part, one of the President's advisor's tells him that civilians can own automatic weapons and silencers so long as they pay a $200 dollar tax on them.
Basically correct for silencers, but omits the fact that since 1986, full auto guns may not be made for civilian hands. There is about 2000 citizens per "transferrable" full auto firearm, thus making them preposterously expensive, and essentially worthless with regard to the intent of the 2nd amendment.