Citing a recent terror attack in the state, an Assembly Democrat is seeking to change how California classifies unfinished firearm frames or receivers.

The proposal, introduced last month, could affect so-called “80-percent lowers,” receiver blanks and other gun components. Backers feel the move is needed to keep guns out of the hands of those who shouldn’t have them.

“Existing law currently allows too much access to individuals who probably should not possess or have access to dangerous firearms,” said the bill’s sponsor, Assemblymember Mike A. Gipson, D-Carson, in a statement. “On the heels of the tragic events in San Bernardino, as well as a number of violent attacks committed with high capacity firearms nationwide, it is critical that we close every potential avenue someone with ill intentions might use to gain access to dangerous firearms.”

Gipson’s bill, AB 1673, would change the definition of a firearm under California law to include, “an unfinished frame or receiver that can be readily converted to the functional condition of a finished frame or receiver.”

Such raw components would have to be regulated in the state just like other guns including having a serial number registered with the Department of Justice, transferred through a licensed dealer, and fall under DROS fee schedules and waiting periods for first-time buyers.

The unregulated sale of unserialized AR-15 style rifles assembled using 80 percent lowers has been a focus of several recent cases in California including the including the controversial seizure of 3,804 unfinished lowers from a retail store in 2014 that the Bureau of Alcohol, Tobacco, Firearms and Explosives deemed to be firearms.

This led the ATF to issue shifting guidance on what does and what does not make an 80 percent lower receiver and lawmakers in California railed against what they described as “ghost guns.”

Last year in the Sacramento area, federal agents seized 238 firearms and silencers, many of which were unserialized, from eight men charged on 70 counts of various gun offenses.

However, Second Amendment advocates argue the latest gun control bill in the Assembly is so broad as to be unenforceable.

“The bill basically says that it has to be readily convertible – but there is no definition of what readily convertible is. The definitions are just outlandishly gray,” Craig J. DeLuz, director of communications with the Firearms Policy Coalition, told Guns.com.

“You’ve got people who don’t understand the technology, they don’t understand the industry, they don’t understand the culture, and so, when they go to write bills they have absolutely no idea what they are talking about. But that doesn’t stop them,” he said.

DeLuz pointed to an example of a homebuilder who constructed an AK-47 style rifle from a shovel as an example of just what could be considered convertible. Further, he found fault with the logic that criminals, who may be prohibited from possessing a firearm to begin with, would be dissuaded from creating one over a requirement that it be serialized and registered.

“So I can go commit my illegal crime, I want to make sure my firearm is legal,” says DeLuz. “Terrorists are not going to go get a serial number.”

Gipson’s bill is currently in the Assembly Public Safety Committee.