Just how many guns do Americans own? (And why do estimates vary so widely?)

since 1994, the last time a detailed, nationally representative survey was conducted, by researchers Philip Cook and Jens Ludwig. The study showed the percentage of Americans owning guns as essentially flat. The rise in privately held guns came from the emergence of hardcore firearm aficionados who represent just 3 percent of all gun owners but individually possess an average of 17 guns each and collectively account for half of the civilian stockpile.

The 2015 National Firearms Survey was based on direct surveys of individual gun owners. Researchers took respondents at their word about how many weapons they owned.

The Small Arms Survey combined and weighted a wider array of sources, including government registries in other countries, academic surveys like the NFS, law enforcement and manufacturing data, and other proxy measures.

Both methods are ways of working around the absence of reliable government data. “There’s no standardized international reporting system,” Karp said. “A lot of countries do nothing to keep track of their civilians’ guns.” 

In the American gun world, estimates are even higher. Some ideologically motivated firearm advocates assert that American civilians own as many as 600 million guns.

Complicating matters further is how or whether estimates account for the number guns that fall out of circulation. The National Firearms Survey, along with researchers Ludwig and Cook, factor a 1 percent annual depreciation rate to the gun supply, to account for the disposal of older guns. But Deborah Azrael of Harvard, who co-authored the NFS report, says the actual rate could be lower. “Nobody really knows how many guns leave circulation each year,” she said.

Knowing the total number of guns in civilian hands isn’t just an academic pursuit. It has implications for law enforcement and public safety policy, since clear records of who owns which guns would make it easier to trace crime weapons and disarm people who commit offenses that make them ineligible to possess guns they had previously lawfully purchased. In the United States, estimates of privately owned guns have political ramifications, too, as candidates and voters debate whether guns should be harder or easier to acquire.

“It will be interesting to see how this new estimate is used,” said Karp. “For some people, it will be irrelevant. For others, it will be instrumental.”

Alex Yablon is a reporter at The Trace. This article is published courtesy of The Trace.