Loopholes as a feature of military fortifications predate both gunpowder and masonry castles, being originally built as angled slits in wooden palisades to give bowmen good fields of fire while affording them excellent protection from enemy bowmen. Loopholes are murder holes, designed to allow one marksman to kill the maximum number of attackers from cover. Loopholes are still used today, especially in city fighting.
The Heritage Foundation debunks the so-called "gun show loophole": "What gun control proponents never say, though, is that this oft-repeated statistic is based on stale data that was grossly exaggerated even when it was fresh."
Long-time readers know that I have written about "loopholes" before, here and here, suggesting that if such a law is passed that we defy it with "Fed-free gun shows."
Maybe we'll get a chance to show the Feds what a "loophole" was originally designed for.