Montana Gun Suit Challenges Federal Authority A Montana lawsuit filed on Thursday challenges federal authority to regulate guns manufactured and sold within the state, an argument that would effectively invalidate federal firearm laws in Big Sky Country if adopted by the courts. The lawsuit arose out of a state law signed by Democratic Gov. Brian Schweitzer that took effect on October 1. It says that firearms, ammunition, and accessories manufactured entirely inside Montana are not subject to federal regulation, including background checks for buyers and record-keeping requirements for sellers. They would remain subject to state regulation, and machine gun manufacturing is not permitted. .