As John Lott reports, the claim that 40 percent of gun sales are by private citizens rather than dealers — meaning no background check is required — is everywhere. Given that the president is going to push for universal background checks, it’s worth getting the number right.
This report from the Johns Hopkins Bloomberg School of Public Health (yes, the “Bloomberg” refers to that Bloomberg) attributes the claim to “data from a nationally representative sample of gun owners,” adding that “data from a national survey of inmates indicated that nearly 80 percent of those who had used a handgun in a crime had acquired it through a transaction with an individual who was not a licensed gun dealer.” While the report has 86 footnotes, these claims are not cited. When PolitiFact inquired about the 40 percent claim, Bloomberg’s office pointed the fact-checkers toward a study from 1997.
The question of where crime guns come from is far more important than the question of where guns in general come from. The 80 percent number seems high based on the survey data compiled here and here, though these numbers are getting old too. Many criminals acquire guns through theft (maybe 15 percent) or buy them at stores (maybe 10 to 15 percent). Others (maybe 30 or 40 percent) obtain them from the illegal market — which just raises the question of where illegal gun sellers get their merchandise. It’s not clear how straw purchases (where the gun is bought from a dealer through a proxy) are classified in many of these surveys. Certainly, that leaves a lot of criminals who obtain guns from private parties, especially family and friends, but we shouldn’t pretend that shutting down private transfers to criminals will shut down gun violence.
Checking the 40 percent number is difficult, but I think it’s worth doing some basic math. There are about 310 million firearms in the U.S., and most recent years have seen 10 to 15 million background checks for gun purchases from dealers. (Background checks do not have a one-to-one relationship to completed sales, but they serve as a decent proxy and we lack other data.) In a year with 15 million dealer sales, it would take 10 million private sales for the 40 percent number to be true, meaning that about 3 percent of privately owned guns would change hands that year.
Put a different way, the average gun would go about 30 years between private sales. This seems plausible to me — more than plausible if we count all transfers, including inheritances — though it would be nice to have good survey data. How long do most gun owners keep their guns, and often do they sell to other individuals rather than trading them in to a licensed dealer? It would be a worthwhile project for the Department of Justice to put together new numbers on these topics as part of its regular surveys (though I remain skeptical that new studies from the Centers for Disease Control would be helpful).