the leftwing anti gun movement is known for massive lies. Example-apply the term "assault" to firearms that are lacking the very feature needed for a weapon to be useful for military assault tactics or talking about a GUN SHOW LOOPHOLE
Until 1968, anyone could buy guns through the mail. Didn't have to fill out forms. But in 1968 that was banned because Democrats-eager to pretend they were doing something about CRIME-and using the fact that President Kennedy's assassin bought his rifle through the mail, passed the GCA of 1968. Then you had to appear and fill out a form to buy a gun. This requirement was based on the rather dubious (constitutionally) claim that since GUN DEALERS engaged in INTERSTATE commerce, congress had the power to force retail buyers to fill out forms and that these dealers maintain them. Congress had also passed a law that prevented a private citizen in say Ohio, from selling one of his firearms to someone who lived in another state-and that Ohio resident could not buy a firearm from someone who lived in another state if that seller was not a licensed dealer
so private sales between non-licensed citizens were LEGAL only if they were INTRA-STATE.
When the Brady bill was passed in 1993, the advocates were not able to muster enough support to make this background check requirement apply to INTRA-STATE private sales. Some who supported the bill when applied dealers (who engaged in INTER-STATE commerce) didn't believe the commerce clause applied to strictly intra-state second hand sales. Others pointed out-correctly (as did the OBAMA DOJ) that while licensed dealers are required to keep accurate logs of all firearms they receive and sell (thus allowing the ATF to enforce the requirement that dealers conduct a background check) private citizens do not, and thus there was no rational way to enforce a private sale background check.
There is no loophole because at gunshows, private sellers are under the same state and federal laws that a guy at a Knights of Columbus or Elk's Club swap meet is under. Dishonest anti gun advocates claim that since there are guns for sale at a gun show-that are being offered for sale by private citizens, that makes it more convenient for criminals to buy there, rather than saying looking at the community newspapers' classified ads and buying that way. But that has nothing to do with the laws and what the Gun haters don't tell you is that unlike private sales instigated by an ad in the newspaper or by word of mouth, Gun shows are crawling with cops, agents and often are being filmed. So while criminals may have more sellers to choose from, they also run a much higher chance of being identified by a cop or have a film of them buying a gun (a felony)