The complaint, which also names the state’s public safety secretary and the State Police as defendants, maintains that the state’s ban illegally extends to the sale or possession of certain rifles, such as AR-15 and AK-47 models, that rank among the most popular in the country.

In a 33-page civil complaint filed in federal court in Boston, the Gun Owners’ Action League, along with several other plaintiffs, asserts the state’s definition of assault weapons is a “non-technical, entirely fabricated, and political term of uncertain definition and scope.”

The Massachusetts affiliate of the National Rifle Association on Monday sued Governor Charlie Baker and Attorney General Maura Healey, contending the state’s ban on assault weapons is unlawful and should be declared “void and unenforceable.”


The lawsuit was in part prompted by Healey’s directive in July to toughen enforcement of the ban on so-called “copy-cat” firearms. The suit contends the directive “vastly expanded Massachusetts’ prohibition to ban an entire class of popular firearms commonly kept for lawful purposes.”

In the lawsuit, the plaintiffs seek to have a federal judge declare both the state’s assault weapons ban, first passed in 1998, and Healey’s July action unconstitutional.

Jay Porter, a lawyer for the plaintiffs, who also include licensed gun dealers and owners in Massachusetts, said the suit was filed in response to what he described as heightened animus toward legal gun ownership in the Bay State.

“The level of hostility to the gun-owning public in the state of Massachusetts has grown to be intolerable,” Porter said. “At this point, it had grown to the level where litigation had become necessary. At some point, if you have a fundamental right, you have to protect it.”

Porter added: “Our position is that the state doesn’t have the authority under the Second Amendment to ban firearms that are commonly kept by responsible law abiding citizens for lawful purposes. ... The Supreme Court has told us emphatically that the government cannot ban popular firearms which are commonly kept for lawful purposes.”


Jillian Fennimore, a spokeswoman for Healey, said in an e-mail that “the assault weapons ban keeps dangerous, military-style weapons off our streets.”

“Since our office issued the enforcement guidance last July, sales of illegal assault weapons have ended in Massachusetts,” Fennimore wrote in an e-mail. “This new lawsuit ... seeks to overturn this 20-year-old law. We will vigorously defend the law.”

Baker’s spokeswoman said the governor “supports the Second Amendment to our Constitution and Massachusetts’ gun laws, including the ban on assault weapons, and the administration generally does not comment on pending lawsuits.”

The other defendants declined to comment.

Healey angered gun rights groups this summer, when she said her office was cracking down on what she termed a loophole that allows customers to circumvent the assault weapons ban by buying “copies” of illegal guns.

She sent a directive to all gun manufacturers and dealers in Massachusetts advising them that assault rifles which have been slightly modified in their bid to pass legal muster — such as the removal of a flash suppressor or featuring a fixed instead of a folding stock — should still be considered illegal because they are functionally identical to the banned weapons.

Days later, a bipartisan group of more than 50 legislators wrote Healey to oppose the move.

In a separate letter, Public Safety and Security Secretary Daniel Bennett, a defendant in Monday’s lawsuit, wrote that Healey’s action had created uncertainty and that people across the state might not be able to figure out which guns are legal and which are not.


In Monday’s complaint, the gun organization and the other plaintiffs argued that Healey’s action “broadly expands the statutory definition far beyond what had been for almost 20 years the settled custom and practice.”

The complaint says Healey’s action “upends decades of settled custom and practice in Massachusetts, retroactively criminalizes decades of legal behavior and transactions” and “exposes the plaintiffs and other gun owners to criminal penalties for exercising their Second Amendment rights..”

John Rosenthal of Stop Handgun Violence, a Newton-based advocacy group, criticized the lawsuit.

“They’re grandstanding,” he said of the plaintiffs. “The courts have ruled that Massachusetts gun laws are reasonable. ... I think [the plaintiffs] will fail.”

In 1998, Massachusetts passed a law that mirrored a federal assault weapons ban passed in 1994. The federal ban expired in 2004, but the Bay State reaffirmed its ban that year.

Monday’s federal lawsuit is not without precedent.

Gun rights advocates have previously filed similar complaints in New York, Connecticut, and Maryland.

Striking down the Massachusetts ban would give gun owners “the exact same level of right to own one of these firearms that the vast, vast majority of millions of Americans all over the country — to own the same firearms everyone else does,” Porter said.

“It restores the Second Amendment rights of the citizens of Massachusetts to those enjoyed by the vast majority of other American citizens,” he said.


Joshua Miller of the Globe staff and Globe correspondents Dylan McGuinness and Jacob Geanous contributed to this report. Travis Andersen can be reached at tandersen@ globe.com.