Another problem with Maryland's law, critics say, is how the state determines who should be banned from owning guns. For decades, the threshold has been people who have been committed to a state-run mental health facility for more than 30 consecutive days.
That has prohibited 42,242 Marylanders from possessing guns, according to state records. But that list has rarely halted a gun sale.
In 2011, just nine out of 46,339 applications for gun purchases in Maryland were denied because of the 30-day rule; 849 other attempts were denied because of the applicants' criminal records and other reasons.
"There's a huge gap," said Montgomery County State's Attorney John McCarthy. "The vast majority of commitments are less than 30 days."
He also said that Maryland should, as the state task force recommended, require therapists to report their clients to law enforcement if they threaten to commit "serious violence" against a particular person or to kill themselves.
McCarthy said there have been dozens of cases in Montgomery in which patients experiencing psychotic episodes or facing other mental health crises have had access to firearms. In 2012, Montgomery police netted 103 guns in connection with emergency mental health evaluation calls, according to county police.
McCarthy wants the state to remove the 30-day rule and to provide state police with a much more comprehensive list of the dangerously mentally ill.
"We're a free society; you're never going to absolutely eliminate potential danger," he said. But "we have to able to intelligently deal with the sharing of mental health information for the safety of police officers on the street," as well as residents in their neighborhoods.
Although O'Malley's plan would not change the 30-day rule, it would require private mental health facilities to share data with the state on patients who have been committed for more than 30 consecutive days. O'Malley's proposal would also require the state to report all of its data to the FBI.