From Guns.com:

On July 22, the State Department’s Directorate of Defense Trade Controls issued new guidance for firearm manufacturers and gunsmiths to register as exporters under the Arms Export Control Act (AECA) and International Traffic in Arms Regulations (ITAR) and pay an annual $2,250 fee — even if they had no intention of exporting. This included companies and individuals who performed machine work on firearms such as threading barrels, magazine modifications and rechambering.