MADISON, Wis. (WFRV) - A 28-year-old Wisconsin man was sentenced to federal prison on Tuesday for turning a ghost gun into a fully functional machine gun. According to a release, Byron Ellison, 28, from Windsor, was sentenced to three-and-a-half years behind bars for possessing heroin and fentanyl intended for distribution and possessing a machine gun. Overnight homicide in Oshkosh, police say a person of interest apprehended Court records show between September 9, 2023, and October 9, 2023, Ellison sold a heroin and fentanyl mixture to an undercover officer on four separate occasions. On October 17, 2023, law enforcement executed a search warrant at Ellison's residence, and in a safe, they found a loaded Polymer 80 9mm handgun with a Glock Switch attached to it. In the same safe, authorities found a Mini Draco AK47 Pistol and 13 grams of heroin and fentanyl mixture. In a backpack in Ellison's room, investigators found a loaded .40 caliber Polymer 80 handgun. According to a release, a Glock Switch is an illegal after-market device that converts a Glock semi-automatic handgun into a fully functioning machine gun. The release from the U.S. Attorney's Office for the Western District of Wisconsin goes on to say that a Polymer 80 is a privately made firearm, also known as a ghost gun, that does not have a serial number. Ghost guns are assembled using components purchased as a kit or as separate pieces. Missing Wisconsin mother and son found dead, hidden on their property being investigated as homicides At Ellison's sentencing on Tuesday, the judge recognized Ellison's lack of criminal history, as this would be his first time being sent to jail. The judge also noted that this was a serious case because Ellison was a drug dealer who had a ghost gun with a switch, allowing him to spray bullets in an indiscriminate manner. The charges against Ellison were the result of an investigation conducted by the Dane County Narcotics Task Force and Bureau of Alcohol, Tobacco, Firearms and Explosives.