Throughout most of our trigger-happy union, it's all too easy to purchase assorted gun parts on the Internet and build yourself an untraceable firearm, effectively outside the reach of federal regulators. It may become illegal to do so in New York City, though, so at least that's something.

On Wednesday, Council Members Helen Rosenthal (D-Manhattan) and I. Daneek Miller (D-Queens) introduced two pieces of legislation, one of which would make it illegal to possess or dispose of unfinished receivers, i.e., the gun frames to which the other components attach. Those pieces may be available online, or even 3-D printed; in any case, the frames lack serial numbers, meaning law enforcement can't easily track them and owners can avoid permitting and background check requirements.

The proposed bill makes possession of an unfinished receiver or frame punishable by a $1,000 fine or a year in prison.

It is unnervingly simple to make a DIY AR-15the gun involved in many of the country's deadliest mass shootings—and even DIY pistols, reportedly the firearm most commonly used in active shooter situations.

As it stands, the NYPD only reports pistols, rifles, and shotguns its officers confiscate during arrests, without releasing numbers on the seizure of 3-D printed and ghost guns, according to a press release. Asked if she had any idea how many of these machines might be floating around the five boroughs, Rosenthal told Gothamist, "How could we know?"

"That's why the whole thing is so insidious," she continued. "You could buy something over the internet that's 80 percent already built, and be given information and go to a hardware store to build the remaining 20 percent. No serial number on anything, completely untraceable."

To help get a better sense of the problem on a local scale, Rosenthal and Miller introduced a second piece of legislation, which would hold the NYPD to tighter reporting requirements when it comes to the seizure of 3D-printed and ghost guns, as well as parts that could be used to make them.

The existence of untraceable weapons scares me a lot," Miller told the NY Daily News. "Having seen the impact of guns on the street, something like this, that can go undetected and untraceable—everything about this is just wrong."

Two states currently regulate ghost guns: California law requires people looking to build their own firearms to apply for a serial number beforehand, or—if they already have the DIY gun in their possession—retroactively, while New Jersey prohibits both ghost parts and 3-D printed parts. Meanwhile, ghost gun legislation pending in the NY State legislature that would, in addition to banning receivers and parts, make it illegal to spread information on how to make untraceable weapons (lawmakers say they still need to work out technical issues, while at the federal level, and the First Amendment complicates efforts to ban information on how to print guns).

Asked why the City Council did not include 3-D printed guns in its proposed ban, Rosenthal noted that this particular issue seems likely to meet a court challenge. Alongside their legislation, though, the council members did introduce a resolution calling for the passage and enactment of a federal bill outlawing unregistered 3-D printed and homemade guns.

"While Congress and the Legislature continue to debate this issue, the Council Members are acting boldly to provide police with the tools necessary to arrest buyers and suppliers, confiscate such firearms, and account for how widely they have spread in order to preserve the safety of all New Yorkers and avert a future tragedy," a spokesperson for Councilman Miller's office said in a statement.

Rosenthal agreed: "New York City could be a leader in clamping down on untraceable guns, and that's what this legislation does: it keeps us in the forefront of getting these guns out of the hands of people who shouldn't own them."