Connecticut has more restrictions on gun ownership than most states, so gun-rights advocates argue the Dec. 14 schoolhouse massacre there illustrates the futility of gun control.

But a new study by a pro-gun control San Francisco organization reaches the opposite conclusion: States with the most restrictive laws, including Connecticut and California, have lower rates of gun-related deaths, while states with few limits on firearms have the highest rates.

In 2009 and 2010, the most recent years for which information is available, California had the nation’s strongest gun controls and the ninth-lowest rate of gun deaths, according to the Law Center to Prevent Gun Violence, which favors firearms regulation. Connecticut had the fourth-strongest gun laws and was sixth-lowest in gun deaths, while Hawaii ranked fifth in gun control and had the lowest death rate.

At the other end of the scale, the report found that Alaska, Louisiana and Montana — all graded F for gun control — had the highest rates of deaths caused by gunfire, more than double California’s rate. The law center graded all 50 states and gave an F, for weak regulation, to 24 of them.

In 2010, the report said, quoting the federal Centers for Disease Control, California had 7.88 gun deaths for each 100,000 residents, compared with rates of 3.31 in Hawaii and 20.28 in Alaska.

More research is needed on the links between specific weapons regulations and fatalities, but “the data supports the common-sense conclusion that gun laws are a significant factor in a state’s rate of gun deaths,” said the report.

Since the report’s release last month, The Chronicle has forwarded it for comment to four gun-rights organizations: the National Rifle Association, the National Shooting Sports Foundation, Gun Owners of America and its state affiliate, Gun Owners of California. None replied to calls or e-mails.

Other recent studies have reached similar conclusions. A researcher at the University of Alabama at Birmingham reported in July that states requiring comprehensive background checks before gun purchases had lower death rates than those without such requirements.

But as long as the federal government leaves gun regulations largely up to each state, the effectiveness of any state’s laws is inherently limited, said Laura Cutiletta, an attorney at the law center that conducted the study.

California, for example, bans most semiautomatic rifles, including the Bushmaster .223 that Adam Lanza used to kill 20 students and six educators at a Newtown, Conn., elementary school this month. But the rifles are legal in neighboring Nevada, and can be taken easily — though illegally — to California.

The Bushmaster is also legal in Connecticut, a circumstance that Cutiletta said illustrates the modest level of gun regulation even in states ranked high in the law center’s survey.

While Connecticut is one of about 10 states with any restrictions on semiautomatic rifles, it prohibits them only if they have certain additional features, such as a pistol grip and a folding or collapsible stock.

The Bushmaster that Lanza reportedly used-was a version of the widely sold AR-15 rifle, and had been legally purchased by his mother, whom he killed before taking her guns and heading to the school.

A federal assault weapons law, in effect from 1994 to 2004, also banned semiautomatic weapons only if they had specific features. Sen. Dianne Feinstein, D-Calif., sponsored that law after a gunman used assault weapons to kill eight people and then took his own life at 101 California St. in San Francisco.

Feinstein is proposing a more far-reaching national law in the wake of the Newtown bloodbath.

Although the federal law has been widely regarded as ineffectual, Cutiletta cited a 2004 study commissioned by President George W. Bush’s Justice Department that found assault weapon use in gun crimes dropped by 17 to 72 percent in six cities during the decade. On the other hand, use of large-caliber ammunition magazines increased through the late 1990s, probably because the ban did not apply to weapons acquired before 1994, the study said.