California’s stringent weapons laws go a long way toward reducing illegal purchases at gun shows without alienating potential customers, finds a leading researcher in the prevention of firearm violence.

Garen Wintemute, a professor of emergency medicine at the University of California, Davis, covertly observed and documented illegal gun sales at 28 gun shows; eight were in California, where shows are tightly regulated, and the rest were in Nevada, Arizona, Texas and Florida.

California requires that gun show promoters be licensed, while the other four states (the leading sources of guns used in crimes in California) don’t regulate shows at all.

Gun shows have long been suspected to be source of guns for criminals, but “before this no one, to my knowledge, has actually gone to these shows and observed what guns were being sold and to whom, or checked whether laws were being adhered to,” said Stephen Teret, director of the Center for Law and the Public’s Health at Johns Hopkins University in Baltimore, who was not involved in this research.

“Now, for the first time, the public policy discussion on gun shows can be based on data rather than speculation,” Teret added.

More ‘straw purchases’

Wintemute saw far more “straw purchases” (where someone with a clean record buys a gun for someone with a criminal record) in unregulated states.

Though these transactions are banned by federal law, most of the straw purchases Wintemute saw were “out in the open, with no evidence that buyer or seller felt the need to hide their conduct,” he said. “So I infer from that that there’s no substantial effort to enforce [the federal law banning straw purchases] at gun shows.”

The sale of assault weapons and undocumented private party gun transactions (which don’t require a background check) were far less common at the California shows, where they are regulated and require background checks.

Private party purchases are another suspected source of guns for criminals. After one such transaction that Wintemute witnessed in which four young men bought eight handguns, a gang unit officer commented, “They’ll just take ‘em out on the street and sell ‘em.”

Wintemute expected California’s stern laws to deter visitors from shows there, but found just the opposite: California shows had more visitors per vendor.

“Gun shows can be regulated so as to diminish their importance as sources of crime guns without greatly diminishing attendance or commercial activity,” he said.

The bottom line, according to Wintemute: “Regulation works.”

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