To prohibit the sale, acquisition, distribution in commerce, or import into the United States of certain firearm receiver castings or blanks, assault weapon parts kits, and machinegun parts kits and the marketing or advertising of such castings or blanks and kits on any medium of electronic communications, to require homemade firearms to have serial numbers, and for other purposes.

3-D Firearms Prohibitions Act This bill establishes new restrictions and prohibitions on the sale, acquisition, and distribution of certain unfinished receivers and parts kits that are used to make firearms. Specifically, the bill does the following: treats unfinished receivers as banned hazardous consumer products, generally prohibits the electronic marketing and advertising of unfinished receivers and parts kits, and requires an individual to obtain a serial number before making a firearm.