A few notes to add...
It’s a federal crime to own an auto without the proper licensing which you much carry at all times with the weapon.
Many thousands to buy these. Converting a semi to full auto is a federal crime.
If the purchase is because of fear of where country is heading, these are tracked weapons. Be the first ones picked up if things fall apart. Any crime committed with a similar weapon means Feds will visit everyone with a similar weapon.
Full auto burns a TON of ammunition. Very fast. Not really suited for hunting or defensive purposes. You’d need a huge stockpile of ammo. It’s expensive. Also very inefficient.
Friend of mine has a collection - all properly licensed. You can burn through a dozen clips in thirty minutes going back and forth. Takes a long time to reload them.
Don’t think this is the direction for the original poster to go.
Don't get a chance to do that much, lately...