Overall, only about 600 such orders have been issued since the law took effect in 2019, according to the State Office of Court Administration.
“As with any public health law, just passing the law isn’t necessarily going to do anything if the people who know about it are unaware of the option,” said Jeffrey W. Swanson, a professor at Duke University who works with the law school’s Center for Firearms Law and studies red-flag measures.
Professor Swanson said that if he were adopting the measure, he would call for a “systematic, administratively driven effort to not only teach people about it, but incorporate it and make a routine of it.”
According to law enforcement officials and his own online diary, Mr. Gendron, who has pleaded not guilty to first-degree murder charges, scouted Buffalo’s East Side to review potential sites for the massacre. On Saturday, the authorities said, he opened fire outside a Tops supermarket, then entered the store and continued to shoot shoppers and workers before eventually surrendering to the police.
On Wednesday, Ms. Hochul, a first-term Democrat who is seeking re-election this year, also urged the Legislature, which is controlled by her fellow Democrats, to pass additional gun safety laws, some of which were already under consideration even before the Buffalo shooting.
Ms. Hochul called specifically for legislation that would require the so-called microstamping of semiautomatic pistols as a way of helping law enforcement officers trace cartridge cases found at crime scenes to the gun that discharged them. Legislation requiring microstamping, which California passed in 2007 over the fierce opposition of gun makers, has long been discussed in Albany, with bills introduced since at least 2009.
The governor, who is from the Buffalo area, has repeatedly expressed concern about the spread of hate speech online, describing it as “a virus” and condemning “social media platforms where this hate can be spewed.”
