Ghost guns – easily assembled firearms without serial numbers – are now banned in Denver

• Because ghost guns are built in parts, buyers can evade background checks from licensed gun dealers.
• Individuals who violate the law may serve up to 300 days in jail and pay up to $999 in fines.

Denver, Colorado Mayor Michael B. Hancock on Tuesday signed into law a bill banning ghost guns, a type of homemade firearm that is nearly impossible for law enforcement to trace because they do not contain serial numbers.

The Denver City Council voted 10-1 to pass the bill, which outlaws the creation, carriage, transportation, discharge, and sale of firearms without serial numbers. Individuals who violate the law may be sentenced to up to 300 days in jail and fines of up to $999, as well as being required to forfeit the weapon, Denverite reported.

Ghost guns are built by purchasing separate parts and assembling them together, allowing buyers to forego background checks that licensed gun dealers perform, The New York Times reported.

Many online ghost gun kits contain partially built firearms, which typically do not contain serial numbers and require buyers to finish their assembly, the Times reported. Law enforcement agencies use serial numbers during investigations to trace guns from their manufacturers back to the original buyer.

Councilmember Kevin Flynn proposed an amendment during the City Council's meeting on Monday that would delay the prohibition of ghost gun possession for Denver residents who already own them. He added that doing so would allow the US Bureau of Alcohol, Tobacco, Firearms, and Explosives time to pass a pending federal rule – expected to be adopted later this year – that would create a way to legally serialize existing ghost guns.

"The immediate effectiveness of this prohibition will mainly impact law-abiding [ghost gun] owners by not giving them a runway period on which they can make deliberate decisions on how they want to proceed," Flynn said during the meeting. "Do they want to dispose of it, destroy it? Do they just want to just render it inoperable until the ATF acts?"

Flynn's amendment was adopted, pushing the date banning the possession of non-serialized firearms until October 1.