In most states in this country it is legal to own an M16, an M60, and even a .50 cal BMG. The feds don’t care care as long as you comply with the paperwork, pay the $200 and get approval. Sawed off shotguns, ditto. Gernades, ditto. Alhough with a $200 tax per gernade, those aren’t on my shopping list.
Kind of, if you have $10,000 to $50,000 or more to purchase the weapon. The law itself so restricts the supply that to say you can own an automatic weapon is a bit of a joke. Its like saying anyone can own a Rolex watch, but that it will be illegal to produce any more Rolex watches.
There is absolutely no reason that an M-16 would cost any more than an AR-15, if the manufacturers were allowed to produce and sell them.
So no, saying that you can just get the $200 stamp is not accurate, as the government has ensured that only a small finite number of weapons exist. That does not consitute free access, when manufacture for sale is prohibited. As a side note, good luck with a grenade. Once you use it, how do you produce it for inspection, as the law requires?