One GOP lawmaker said Attorney General Maura Healey’s new push to ban so-called “copycat” assault rifles will likely face legal challenges, at least before legislators can find time to address her crackdown.

“I expect there will be lawsuits of this overreach of power, of redefining a product the way she has,” said state Sen. Don Humason, a Westfield Republican, adding that with only a handful of sessions before the July 31 deadline, Healey’s ban left concerned lawmakers little time to study it.

Humason said he was on a conference call with Senate Republicans, members of Gov. Charlie Baker’s staff and others Thursday evening to discuss Healey’s vow to crack down on the rifles, though there was confusion about what “options” were left for lawmakers.

“It seems like the clock is against us. This is not going to be a short game,” said Humason, adding he was “shocked” by the AG’s move. “Because of the timing, this is likely going to be resolved by a lawsuit instead of legislative action.”

Baker’s office said yesterday “many are expressing confusion with the application and timing of the AG’s action,” and the Swampscott Republican has asked Healey’s office to clarify the order for gun owners. Many of them wonder how they will be protected from prosecution if they legally purchased guns which resemble AR-15s and AK-47s but are now considered banned under Healey’s order.

The Gun Owners Action League — which is planning a rally at the State House this morning — is already warning members not to take assault rifles to the gun range, its executive director, Jim Wallace, said. The Herald reported that the state recorded nearly 2,600 rifle sales alone on Wednesday — the day of the AG’s announcement — up nearly 20-fold from roughly 130 the day before.

Healey’s office said it won’t prosecute those who purchased the guns by the end of business Wednesday.

“Our office will continue to work with the gun industry, including manufacturers and dealers, to make sure they understand our enforcement notice and comply with the law to keep these deadly guns off our streets,” her office said.