As others have pointed out. Calling it a loophole is just trying to prejudice the discussion. Dealers have to complete background checks and some places private sellers do not have to complete background checks.
It is only a loophole if you think the mortgage interest deduction is a loophole. It is not some narrowly crafted exemption designed to privilege some small group. Most private gun owners are not even required to keep track of their guns. I don’t have a record of what guns I have bought, sold or given away. I don’t even have a list of what I currently own. I do have pictures of probably 90% of the guns I have owned but some of the pictures are of guns I don’t have anymore. Of course, some of my guns are not “guns” under federal law. Muzzleloaders, guns made before 1898, air rifles, etc.
TEK