Chicago outlawed the sale and possession of handguns in 1982. This month, the U.S. Supreme Court is considering a challenge to a similar law in Washington, D.C., and a victory by gun-control opponents in the high court might end up striking down the Chicago ban. But how effective has Chicago’s ban actually been? Hard to say.

Despite its ban, Chicago tops the nation in confiscated firearms. Last year, Chicago police seized about 7,400 guns and received 6,000 at voluntary turn-ins. Over the past decade, Chicago police have confiscated an average of 10,800 guns per year. Chicago Police spokeswoman Monique Bond sees the high confiscation numbers as evidence that guns are ubiquitous here: “Anyone can get a gun,” she says. “You can get a gun like you can get expensive sneakers.” But she insists those statistics also reflect that law enforcement has been aggressively cracking down on guns in the city.

Still, a recent study published in The Economic Journal found that guns are harder to buy in Chicago than most people think. One of the study’s authors, Sudhir Venkatesh of Columbia University (whom Chicago interviewed in January à propos his new book, Gang Leader for a Day), talked to gang members, prostitutes, gun-owning youths, gun dealers, and others in the Grand Boulevard and Washington Park neighborhoods. The study found that the police crackdown on illegal guns makes them harder—and more expensive—to obtain. Underground brokers sell guns for $150 to $350, typically double the legal price. They also demand a fee of $30 to $50 for orchestrating the deal. Even then, 30 to 40 percent of the transactions fall through because the seller cannot secure a gun, gets cold feet, or cannot agree on a location for the deal. “There could be a small number of people walking around who know exactly where to go to get a gun,” says University of Chicago professor Jens Ludwig, one of Venkatesh’s co-authors. “But the majority of people don’t.”