You CAN NOT have BATFE controlled weapons sent directly to you.
The only exception is if you have a Dealers License.
If you are a dealer, then you are getting all the discount and trade papers sent to you and you can buy about everything much cheaper anyway!
BATFE controlled weapons include anything that post dates the 1937 firearms act,
In most cases, anything that fires a cartridge instead of loose power and bullet,
And anything that is considered a 'Dangerous or Destructive Device',
Including, but not limited to,
Any firearms that fires a projectile 1/2" (0.050") in diameter,
(and that DOES mean potato guns are illegal)
Any firearm that will fire fully auto, meaning it will fire more than one round each time the trigger is depressed,
Any device that will make/cause any firearm to fire more than one round per trigger pull,
Any device that will change the status of a fire arm,
As in the cartridge cylinders being sold for black power pistols. Installing the cylinder changes the status of that pistol/rifle to a modern cartridge firing gun, and you MUST register and be licensed to carry it after that.
Any device that is intended to lessen the report of the firearm,
The list goes on, but you get the idea...
(all the fun stuff!)
Gun Broker and all those places CLEARLY STATE that you will need to have a LICENSED FIREARMS DEALER receive the firearms you buy...
That means you have to cut that guy in on the deal to do the paperwork for you.
What CAN be purchased over the internet,
(Depending on what state you live in...)
Ammo, you can buy as much ammo as you can get UPS to ship!
Muzzle loading weapons, classified as needing to be manually loaded with loose power and projectile (bullet).
Replacment parts for fully automatic weapons.
Be careful on this one!
Being in possession of a receiver that will accept, and 3 or more of the automatic parts constitutes a 'Machine Gun' or 'Automatic Weapon' even if you don't have the thing put together...
Example: If you have an AR-15 rifle, and you have 3 or more M-16 trigger group parts,
Even if they aren't put together,
In the eyes of the law it's still a 'Machine Gun'.