IL HB4550

Increases penalty for first violation of possessing, transporting, purchasing, or receiving an unfinished firearm frame or receiver from a Class A misdemeanor to a Class 4 felony, effective 180 days after enactment.

Prohibits possession of unserialized unfinished frames or receivers unless the person is a federal firearms importer/manufacturer, transferring to one, or the frame has been imprinted with a serial number by a federal licensee.

Requires unserialized firearms and frames produced using three-dimensional printers to be serialized within 30 days of enactment or before reaching a stage where it may be readily completed or converted to a functional firearm.

Mandates that federally licensed firearms dealers serialize unserialized frames and firearms using their abbreviated federal license number as a prefix (first 3 and last 5 digits) followed by a unique suffix number, in compliance with federal law.

Exempts permanently inoperable firearms, antique firearms, and firearms manufactured prior to October 22, 1968, as well as unfinished frames possessed by bona fide suppliers for transfer to federal manufacturers.