How does the state define a Business selling firearms and a hobbiest/collector?

[Special T]

I think we all know certain individuals who seem to buy, and likely sell lots of firearms. So it got me thinking. How does the state define a hobbyist who buys shoots then sells guns VS a Dealer? I have bought and sold some weapons, but likely not enough to raise any Does anyone have any insight to this situation/ the ability to protect ones self if i decided to sell off a bunch of guns?

[Biggerhammer]

Who cares!! 

[Special T]

If they don't then thats great, but i can think of at least one hobby that they do  make some specific limitations.

[Biggerhammer]

In all seriousness, I have never researched it.