@Baldimo,
You have to be kidding me. Do you really believe there are no internet sales of weapons and ammunition through the mails? Do you really believe there are no personal sales bypassing Federal Licensed dealers? Do you really believe you can't come here to Texas and buy almost anything you want at a "gun show" and take it anywhere you want?
Cause if you do, man do I have a bridge over "prime" Florida wetlands for you.
I almost wish you lived close enough I could take to a gun show in Austin and show you how to buy a full on rock and roll M-16 or AK-47. Or an M-4,or a ........... no waiting or anything, budget between $800 for the AK to $2000/$2500 for the M-5, same day delivery, no sort of registration just like any other "legal" firearm at a "gunshow". The only limitation is: no ammunition is sold at a "gunshow". Except in the parking lot.
Where do you live? I am sure I can find you the weapon you need. If you're in Mass or NY, to save money you buy out of state. For NY, NJ will do nicely.