The legal attack on federal gun control started earlier this year in the Legislature.

Legislation said that guns manufactured in Montana and sold in Montana are exempt from federal gun registration, background check and dealer-licensing rules because no state lines are crossed.

The measure was signed by Gov. Brian Schweitzer.

The Bureau of Alcohol, Tobacco, Firearms and Explosives has already warned Montana gun dealers that federal law reigns supreme on the issue.

But gun advocates hope to get the courts to rule that Congress has overstepped its constitutional bounds by regulating activity that stays inside of Montana.