Face to face with a Wisconsin resident who is an adult and affirms that they are not a felon or otherwise prohibited from owning a firearm, is a cash and carry, no paperwork deal; both pistols and longarms.
All out of state hand gun sales must go through an FFL.
Face to face long arm sales to a resident of a contiguous border state is okay, unless state laws prohibit it. IL residents are a no-go. MI and MN residents can buy your long arms face to face.
Long arm sales to residents of not-touching states must go through an FFL
If you setup a sale to an out of stater that requires shipping ....... good luck.
Carriers are finicky about shipping arms, and some FFLs wont receive an arm from a private citizen.
This means that you may end up in a predicament where you have to pay an FFL to ship the gun on your end, and the recipient has to pay an FFL to receive and paper the gun on his end.
Most of us elect to swap all of our stuff around in-state to other residents.
It's fool proof that way, ... everything not-class-3 is okay to trade like baseball cards.
No headaches.
PM headed your way.