The bill has been introduced by Rep. Honda (D-CA of course):

Considers as a banned hazardous product under the Consumer Product Safety Act: (1) any firearm receiver casting or firearm receiver blank (do-it-yourself assault weapon) that does not meet the definition of a firearm under the federal criminal code at the point of sale but that can be completed after purchase by the consumer to function as a firearm frame or receiver for a semiautomatic assault weapon or machine gun, or (2) an assault weapon parts kit or machine gun parts kit.

Makes it unlawful to market or advertise any of such weapons for sale on any medium of electronic communications, including over the Internet. Requires marketing or advertising violations to be treated as unfair or deceptive acts or practices under the Federal Trade Commission Act.