As lawmakers push to toughen gun sale rules amid outrage over random mass shootings like the November massacre at a Thousand Oaks country music bar, a new federal study says few criminals who had a gun bought it from a retailer.

According to the January special report by the U.S. Department of Justice's Bureau of Justice Statistics, about one in 10 state and federal prisoners convicted of crimes involving a firearm said they got the weapon through a retail source like a sporting goods store, pawn shop or gun show.

Both sides in the debate over toughening gun laws said the study, based on interviews with 20,064 state and 4,784 federal prisoners, supports their argument.

Gun-rights advocates argue it bolsters their case that laws making it harder to legally buy guns aren't keeping them out of criminals' hands and only vex the law-abiding citizens who buy guns for sport or protection. The findings, they say, are consistent with similar surveys in 1997 and 1991.

"The report appears to underscore the fact that violent criminals generally don't follow the law," said Brandon Combs, president of the Sacramento-based Firearms Policy Coalition, a gun-rights advocacy group.

But advocates for tougher gun laws said the findings support their argument that restrictions on who can buy firearms frustrate criminals who must turn to riskier, illegal sources.

David Chipman, who worked 25 years for the Justice Department's Bureau of Alcohol, Tobacco, Firearms and Explosives and is now a senior policy adviser for the Giffords Law Center to Prevent Gun Violence, likened it to a finding that burglars avoid homes with alarms.

"I'd go out and buy a burglar alarm," Chipman said. "The other side of this debate saw that study and said, 'Oh, it's proof that all this is meaningless.' But it seems to me that if the rarest occasion where a criminal gets a gun is in a regulated space, then we want more sales regulated."

California has the country's most comprehensive gun regulations, the only state the Giffords Law Center gives a solid "A" rating. California bans military-style semiautomatic "assault" rifles, restricts high-capacity ammunition magazines and imposes a 10-day waiting period on gun purchases. All sales must go through licensed dealers who conduct background checks on buyers. Buyers are limited to one handgun purchase a month. Family members can obtain a court order to disarm a mentally unstable relative.

Large capacity magazines for rifles and pistols, seized by the Oakland Police Department, sit on an evidence room table at department headquarters, Tuesday, Feb. 19, 2013 in Oakland, Calif. (D. Ross Cameron/Staff)

A 2016 California initiative to ban all high capacity magazines and require background checks for ammunition purchases is being challenged in court by gun-rights groups. But state lawmakers recently added new restrictions, including raising the age to buy a rifle to 21, the same as for handguns. And newly elected Gov. Gavin Newsom has vowed to go further, saying he would sign additional gun laws his predecessor, fellow Democrat Jerry Brown, vetoed.

Most of those regulations involve retail purchases.

The Justice Department study said that armed criminals' single biggest source for guns is the black market. More than 43 percent of the surveyed prisoners who had a gun during their crime got it on the streets in the underground or black market.

One in four said they got their gun through family or friends who either sold, lent or gave it to them as a gift. Only 6.4 percent said they stole their gun, almost as many as the 6.9 percent who said they got it at the scene of the crime — often from their victim.

Of the 10.1 percent who got their gun from a retailer, 7.5 percent said they bought it at a store, while 2 percent went to a pawn shop or flea market and fewer than 1 percent said it came from a gun show.

Steve Lindley, a Los Angeles program manager for the Brady Campaign to Prevent Gun Violence, noted that the study is based on the word of convicted criminals, and criminals' words should be taken with a grain of salt. "They might not be the most honest individuals," he said, adding even black-market guns started out with a legal sale, and laws that help trace their path to criminals' hands help.

Chipman said the study shows the effectiveness of retail sales controls and the problem of having looser rules in other states. For example, many states allow gun owners to sell their firearms privately instead of through licensed dealers who perform background checks on the buyers.

Sales associate Mike Conway, right, ...
In this Dec. 9, 2015, file photo, sales associate Mike Conway, right, shows Paul Angulo guns at Bullseye Sport gun shop in Riverside, Calif. With six new gun control bills signed by California's Gov. Jerry Brown in July 2016, sales of semi-automatic rifles have more than doubled in California over last year.

"There's a whole host of reasonable regulations if you go to a gun store, but if you're outside a gun store there are few if any regulations, at least at the federal level," Chipman said. The study, he added, "supports the notion that requiring people to go to gun stores makes it more difficult for them to get guns."

But John Lott, an economist and president of the Crime Prevention Research Center who was on the United States Sentencing Commission in the 1980s, said the study bolsters his skepticism of gun restrictions.

Lott likens gun laws to alcohol prohibition and the "war on drugs," which he notes did little to quench drinking and drug abuse while enriching black-market bootleggers and drug cartels. And he points to Mexico, which has some of the world's strictest gun laws — Mexicans can only buy small-caliber firearms from a single, government-run seller — yet it is awash in violent crime.

"In Mexico there aren't powerful guns to steal from citizens, yet the criminals still go and get guns," Lott said. He argues that making legal purchases easier, as was done with drugs and alcohol, is more effective thwarting criminal cartels trafficking in contraband, whether liquor, drugs or guns.

Even with all California's gun-sale restrictions, felons still manage to get guns without any help from other states. In San Diego County, a public defense lawyer, Andrea Bayer, pleaded guilty in October to providing a gun to a felon — apparently twin brothers facing attempted murder, arson, drug and weapon charges, their father told the San Diego Union Tribune.

Chipman acknowledged that "criminals will adapt" to every law aimed at thwarting them, but he said those laws still make it harder for them to commit crimes.

"What we're focused on is progress," Chipman said, "not perfection."