The recent shooting deaths of nine people inside a Charleston, South Carolina, church resurfaced one of the least-discussed aspects of the country’s easy access to guns: giving guns as gifts to family members.

Early reports indicated that Dylann Roof, the 21-year-old man charged with the killings, received the Glock .45-caliber pistol believed to be used in the shooting as a birthday present from his father. Although subsequent media reports discounted that version of events, suggesting Roof bought the gun himself with money from his parents, questions linger about the lack of oversight of family gun transfers.

In most states, giving a gun to a family member such as a son or granddaughter is easier than giving him or her a car. In fact, guns changing hands among family members is among the least-regulated aspects of gun ownership.

South Carolina is one of 33 states that require no background checks for any kind of private-party transfers. Federal law requires only licensed gun stores to conduct background checks, often referred to as the gun show loophole.

Most of the handful of states that do require background checks for private-party sales have special exemptions for giving guns to family members. These include Colorado, California, Delaware, Illinois, Nebraska, Pennsylvania and Washington, according to the Law Center to Prevent Gun Violence.

As advocates of so-called universal background checks renew calls to close the private-sale loophole, family transfers haven’t been the subject of any proposed legislation, said Mike McLively, an attorney at the San Francisco-based law center.

And prospects for changing that appear to be slim.

Two members of Congress, a Republican and a Democrat, introduced joint legislation in the aftermath of the 2012 mass shooting that killed more than two dozen people at Sandy Hook Elementary School in Connecticut that would have required background checks at gun shows and for online sales. But the bill didn’t draw enough support from the Senate, which appears even more divided on guns now than it was then.

It’s unclear how many guns get passed around by families because most states do not maintain records for that.

In California, which has some of the country’s strictest rules on gun purchases, at least 51,672 guns have been transferred among family members since 2010, according to data maintained by the state Bureau of Firearms, a branch of the Department of Justice. The vast majority, more than 9 out of 10, were handguns. Of those, most were semi-automatic pistols like the one Roof is believed to have used to kill nine churchgoers in Charleston.

But these guns are dwarfed by the new and used guns purchased from licensed dealers every year. More than 931,000 guns were sold in California in 2014 alone, a number that has risen steadily for more than a decade.

California’s rules on family transfers are more lax than for other private-party transfers. A background check isn’t completed until after the gun changes hands.

“It’s definitely not the ideal way to do it,” McLively said. “Fifty thousand guns is not an unsubstantial number.”

For nonfamily transactions in California, gun stores act as a middleman and hold onto the gun while the state conducts a background check. The gun doesn’t actually change hands for at least 10 days while this takes place. But when Californians give guns to their children or grandchildren, they don’t need to go through a licensed gun store. A parent or grandparent needs only to write a note saying the gun is a gift.

California’s policy applies only to guns transferred from parents or grandparents to adult children or grandchildren. Transfers between siblings or extended family members are not exempt from normal state requirements.

A handful of other states regulate family gun exchanges in varying ways. In Illinois, extended family members also are exempt from background checks. Delaware exempts legal guardians, too. In Nebraska and Washington, a background check isn’t required to transfer antique guns, which covers heirloom guns.

In California, a family recipient must obtain a safety certificate – a basic multiple-choice questionnaire – from a state-certified gun store and has 30 days to submit a form and $19 to the state Department of Justice, which conducts a background check to ensure he or she is legally allowed to own the gun.

If a recipient fails the background check, he or she is added to the state’s database of armed and prohibited persons. Local and state law enforcement then are assigned to go the person’s home to take away the gun. But this process can take months or even years, as the state continues to struggle with the backlog of gun owners banned from possessing a gun.

Matt Drange is a reporter for Reveal, covering the business of guns. He previously reported on Silicon Valley and the intersection of technology and the environment. He won a James Madison Freedom of Information Award from the Society of Professional Journalists' Northern California chapter for his work on the Toxic Trail investigation, which exposed how mismanagement of Superfund cleanup sites often leads to substantially more harm than good. Prior to joining Reveal, Drange worked for the Maine Center for Public Interest Reporting, where he wrote about malfeasance in state government and the influence of money in politics. Drange started his career covering police and courts for the Eureka Times-Standard in California. He earned a master's degree from the Columbia University Graduate School of Journalism and did his undergraduate work at Humboldt State University. Drange is based in Reveal's Emeryville, California, office.