I like most of your answer, but didn't like that you silently dropped "newly-made" from the OP's criteria. You're welcome to argue that it doesn't matter, and just as welcome to argue that this is a good thing, but it seems odd to avoid mentioning that there is no legal way for a US citizen to purchase a fully automatic weapon manufactured after 1986 --- and that guns not subject to this ban are in very short supply and thus very expensive: https://en.wikipedia.org/wiki/Firearm_Owners_Protection_Act