Source: United States Bureau of Alcohol Tobacco Firearms and Explosives (ATF)
Jacksonville, Florida – U.S. District Judge Harvey E. Schlesinger has sentenced Jason Stewart Karst II (37, Fleming Island) to six years in federal prison for possessing a firearm as a convicted felon. Karst entered a guilty plea in March 2025.
According to court documents, in April 2024, agents with the Bureau of Alcohol, Tobacco, Firearms, and Explosives received a complaint from a local shooting range that Karst and another individual had been shooting fully automatic firearms at the range. Surveillance video from the range showed Karst firing a fully automatic gun as well as a separate gun that was equipped with a silencer. Agents obtained a search warrant for a home owned by Karst and executed the warrant on May 1, 2024. During the search, agents found five silencers, a privately manufactured firearm that was equipped with a machinegun conversion device, and a pistol that was also equipped with a machinegun conversion device inside a large safe. The guns matched the appearance of the ones used by Karst at the shooting range. In addition, while agents were executing the search warrant, Karst drove up to the house. During a search of Karst’s car, officers with the Jacksonville Sheriff’s Office found a white powdery substance, over 20 grams of marijuana, a scale, a pistol without a serial number, and keys to the safe.
Karst was previously convicted of multiple felonies, including two convictions for possession of marijuana with the intent to sell or deliver, possession of a controlled substance with the intent to sell or deliver, attempted use of a minor to deliver a controlled substance, and possession of a firearm by a convicted felon. Therefore, he is prohibited from possessing firearms or ammunition under federal law. Additionally, contrary to federal law, the machinegun conversion devices and silencers were not registered in the National Firearms Registration and Transfer Record—a database maintained by the Bureau of Alcohol, Tobacco, Firearms and Explosives.
This case was investigated by the Bureau of Alcohol, Tobacco, Firearms and Explosives, Clay County Sheriff’s Office, and the Jacksonville Sheriff’s Office. It was prosecuted by Assistant United States Attorney Elisibeth Adams.
This case is part of Project Safe Neighborhoods (PSN), a program bringing together all levels of law enforcement and the communities they serve to reduce violent crime and gun violence, and to make our neighborhoods safer for everyone. On May 26, 2021, the Department launched a violent crime reduction strategy strengthening PSN based on these core principles: fostering trust and legitimacy in our communities, supporting community-based organizations that help prevent violence from occurring in the first place, setting focused and strategic enforcement priorities, and measuring the results.