BOSTON (CBS) — Massachusetts Attorney General Maura Healey says she’s cracking down on the sale of guns that have been modified to skirt the state’s assault weapons ban passed in 1998.

She says the gun industry has openly defied the law, and she’s stepping up enforcement, especially in the wake of the mass shooting at an Orlando nightclub and the shootings of police officers in Dallas and Baton Rouge.

Healey says she is referring to weapons that she says have been “tweaked” to become so-called state compliant.

“If a gun’s operating system is essentially the same as a banned weapon, or a gun’s component parts are interchangeable with those of a banned weapon, it’s a copy and it’s illegal,” said Healey.

Despite the law, Healey estimates some 10,000 copycat assault weapons were sold in Massachusetts last year. While manufacturers have deemed certain weapons in compliance, she said her office looked at the issue and concluded they weren’t.

.@MassAGO: both of these weapons are illegal to sell and possess in MA, but one is marketed as "MA compliant" pic.twitter.com/Sq5DFMigzM — Bernice Corpuz (@BerniceWBZ) July 20, 2016

But John Costa, owner of The Gunrunner gun and ammunition store in Middleborough disputes Healey’s directive saying she’s trying to rewrite the regulations. “Don’t you think these manufacturers check with their attorneys? Don’t you think their attorneys would be telling them what it should be to sell these guns?”

Costa insists a modified assault weapon that has only two of the original components is legal under Massachusetts law. He says his phone has been ringing off the hook from worried gun owners.

A long line of people waiting outside a gun dealer in Woburn, outraged over @MassAGO's #assaultweapons announcement pic.twitter.com/ebCSIlAGtS — Bernice Corpuz (@BerniceWBZ) July 20, 2016

After Healey’s press conference, dozens of customers waited outside Four Seasons Firearms in Woburn hoping to buy the type of guns now deemed illegal. “If I knew this was coming I would have bought a lot of guns before this happened,” a man told WBZ’s Bernice Corpuz.

The AG warned gun dealers about the assault weapons ban just a day before. Gun owners say the new policy is unconstitutional and say the one day notice was unfair.

“It definitely is not fair,” another customer said. “This is a backhanded move, she did it by surprise didn’t give anybody a chance to do anything, be prepared, for it, just surprise here it is.”

Healey says she has sent a directive to more than 300 dealers in Massachusetts and wants to work with them to clear up any confusion, but hasn’t ruled out the possibility of inspections and fines.

WBZ NewsRadio 1030’s Bernice Corpuz reports

