there are actually a handful of rogue dealers which something on the order of 40% or more of guns pass through on their way to crimes. and there are no federal requirements for dealers to keep an inventory of guns sold. i'm sure there are laws for prosecuting dealers who sell to criminals, but they are rarely enforced. or at least, rarely make the news when/if they are. the kids at columbine got their guns through a dealer who sold it to a friend who was 18. there are shops who sell to gangs and other criminals throughout the country, but the ATF can't prosecute them for various reasons. if anything at all comes from the passage of new legislation, i would be perfectly happy if these dealers were shut down for good.
Federally liscensed dealers (basically all of them) are required to keep a record of all gun sales (failure to do so caries heavy penalties). Those records are available to law enforcement via a court order. The laws against illegal sales are enforced, except when the Justice Department decides to not enforce them and instructs dealers to complete the illegal sales.
http://www.atf.gov/firearms/faq/licensees-records-required.html
http://www.eveningsun.com/news/ci_22690488
Criminals don't buy from gun shops, because they can't pass the background check, they buy from individuals, at inflated prices. Individuals that are a member of a gang who have not yet become criminals can, but rarely do because the transactions are recorded.
As for the Columbine shooters, the individual who obtained them the weapons was the criminal,and subject to 1 to 10 years (depends on if he suspected criminal intent by the minors) in prison for each offense, not the gun dealer who complied with all federal laws regarding the sales and kept records of the sales.
the bill designed to stop trafficking as a felony offense would have made the dealer who sold the gun to the straw buyer at Columbine an accessory to a crime. there are literally thousands of instances every year of people who go into stores with someone who can pass a background check, point out the gun they want, get the other person to buy it for them, and then take the gun home themselves rather than the person whose name is on the books.
as for inventory, let me refer you to a store formerly called "Badger Guns" in Wisconsin. In one year, they reported over 600 "lost" guns and had their license revoked after a multi-year process. their guns were traced to SIX separate incidences of cops getting shot. despite the lax enforcement of the law, the store has had its license revoked twice in the last decade. but yet the same family still owns and operates the store, having passed it from father (license revoked) to son (license revoked) to second son (license still current as of 2010). read up on "Realco Guns" in Maryland and tell me again how the laws are so strict on gun dealers. http://www.washingtonpost.com/wp-srv/special/nation/guns/
we also have the so-called "Tiahrt amendment" which prohibits the collecting of data for any but law enforcement purpopses, and prohibits the release of that data to anyone not involved in law enforcement. we are told that this is to prevent the gun dealers from lawsuits, but in reality the way this works is that when/if the ATF inspects a store the best they can do is issue a warning not to lose so much paperwork. if the store has repeated issues, the ATF can recommend revoking the license, but it can take up to two years to revoke a license, during which time the store can continue to sell. if a license gets revoked, the owner can simply have a family member or friend apply for a dealer license and reopen the shop with "new management" but still practicing the same as before. the ATF is also prevented from asking for documents to prove the new licensee is not just trying to skirt the law. if you want to enforce the laws we already have, then lets get rid of the handcuffs and let the law enforcement do their jobs the way they were meant to. otherwise, i'm not really seeing how having weak laws with no enforcement is making anyone any safer.
"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman