Yesterday, the Philadelphia City Council approved a ban on the manufacturing of guns with a 3D printer.

Philadelphia magazine reports that councilman Kenyatta Johnson, who crafted the legislation, is unaware of any actual 3D gun manufacturers in the city, and in a surprisingly earnest statement Johnson's office explained that "It's all pre-emptive. It's just based upon internet stuff out there."

The legislation, which bans anyone without a federal firearms manufacturing license from producing 3D-printed guns, was passed unanimously by 10-member council. If the mayor approves the bill, Philadelphia will be the first city to implement this kind of ban.

Johnson, who is a longtime advocate of restrictions on gun ownership and use, previously said "You can use certain types of plastics and certain types of other material to replicate anything," a power that if honed by 3D gun enthusiasts could be "catastrophic." He hopes that restricting these firearms will be curtail violent crime in Philadelphia.

It's an ambitious goal. The Department of Homeland Security, for example, has suggested that stopping the production of 3D-printed weapons is a virtually impossible task. And criminals may have little incentive to buy or build plastic 3-D printed guns like the Liberator, which is likely to complete just a few shots before breaking. The production of metal 3-D printed guns may change that, but as Philadelphia magazine notes, the equipment needed to manufacture one of these firearms can set you back $8000, whereas a good old-fashioned black market handgun may cost as little as $300. If a criminal is looking to inflict the catastrophic damage that Johnson fears, they would not need an expensive, futuristic gun, but as Reason's J.D. Tuccille highlights, a coffee mug, few dollars worth hygienic products, and a working knowledge of basic chemistry.

There also remains question as to how well the bill will hold up, as Pennsylvania law states that "no county, municipality or township may in any manner regulate the lawful ownership, possession, transfer or transportation of firearms, ammunition or ammunition components when carried or transported for purposes not prohibited by the laws of this Commonwealth."

Johnson countered this, telling Phily.com that "the prohibition that city ordinances can't overcome as it relates to state legislation is primarily ownership, transfer of a firearm. This goes to manufacturing." He assured that "We believe that if there is a challenge in the court system, it will be something we'll be able to defeat."