Prevent Gun Trafficking Act This bill establishes new federal criminal offenses for gun trafficking and related conduct. First, the bill establishes a stand-alone federal criminal offense for gun trafficking. A violation is punishable by a fine, a prison term of up to 10 years, or both. The bill also authorizes the seizure and forfeiture of the firearms and ammunition involved in the offense, the property involved in the offense, and the proceeds (or property traceable to the proceeds) derived from the offense. Second, the bill makes it unlawful to sell or dispose of a firearm or ammunition to any person knowing or having reason to believe that the person intends to sell or dispose of the firearm in violation of a federal law, or to sell or dispose of the firearm to a person in another state in violation of that state's law. A violation is subject to existing penalties under current law—a fine, a prison term of up to 10 years, or both. Current law already authorizes the seizure and forfeiture of firearms and ammunition involved in the offense. This bill also authorizes the seizure and forfeiture of the property involved in the offense and the proceeds (or property traceable to the proceeds) derived from the offense.