I have never purchase a firearm and done any paperwork. I have also never done any paperwork when I sold a firearm. I once bought a pistol at a gun show and gave my license info to a non commercial dealers, he said it was for his own protection, but didn't go anywhere. What are the requirements legally to purchasing and selling a firearm in WA state. Is a bill of sale required, is there state paperwork that needs to be filed?