Duluth man accused of 3D-printing machine gun conversion kits

A Duluth man is accused of using 3D printers to make machine gun conversion kits, putting a cheap consumer tool at the center of a serious weapons case in St. Louis County. Authorities say Jordan Bach Otis, 34, of Duluth, was arrested last week amid an ongoing investigation into alleged drug and gun crimes.

The parts at the heart of the case are commonly called switches, auto sears or drop-in auto sears. The U.S. Department of Justice says federal law treats machinegun conversion devices as machineguns even when they are not installed on a firearm, because they can turn semiautomatic weapons into fully automatic guns in seconds. The Bureau of Alcohol, Tobacco, Firearms and Explosives says the devices can be made through additive manufacturing, including 3D printing, and has warned that 3D-printed machinegun conversion devices are illegal under federal law.

The Duluth arrest fits a pattern federal prosecutors and agents have described elsewhere in Minnesota. In a Sept. 7, 2022 case in Minneapolis, federal agents found four 3D printers and multiple 3D-printed auto sears in a residence during an investigation involving Homeland Security Investigations, the ATF, U.S. Customs and Border Protection and the Minneapolis Police Department. In another Minnesota case announced Sept. 15, 2023, prosecutors said a Snapchat group called BLICCS&STICCS3 was used to traffic machineguns, firearms and controlled substances. Undercover officers also bought Glock switches in St. Cloud and St. Paul, showing how the devices were moving across the region.

Federal officials have increasingly tied these devices to broader criminal activity, including drug trafficking and ghost-gun cases. A Jan. 10, 2025 Justice Department commentary said at least 23 states and the District of Columbia had enacted bans on machinegun conversion devices, and listed Minnesota among states with separate prohibitions against possession.

For investigators in Duluth and across St. Louis County, the case underscores how a weapon part once associated with specialized crime can now be produced with a printer, moved quietly and folded into a wider drug-and-gun probe before it reaches the street.