Ken,
On the rule of 4/year keep it in mind with the following:
- To differentiate someone who is just selling "some stuff", but not making a business out of it, they set an arbitrary limit of 4 guns/year.
- To sell more, they require that you get licensed as a dealer and meet all the dealer requirements (e.g. zoning, safes, alarm systems, insurance, etc.).
Just as an FYI, there is a very similar law on allowing only x cars/year to be sold privately (I think x=5). After that you need a dealers license. I remember this because as a teenager, my barber's Son was always buying cars, fixing them up and selling them and this was mentioned more than a few times while I was in the barber shop.