AN ACT EXEMPTING FROM FEDERAL REGULATION UNDER THE COMMERCE CLAUSE OF THE CONSTITUTION OF THE UNITED STATES A FIREARM, A FIREARM ACCESSORY, OR AMMUNITION MANUFACTURED AND RETAINED IN MONTANA; AND PROVIDING AN APPLICABILITY DATE.
BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF MONTANA:
Section 1. Short title. [Sections 1 through 6] may be cited as the "Montana Firearms Freedom Act".
Section 2. Legislative declarations of authority. The legislature declares that the authority for [sections 1 through 6] is the following:
(1) The 10th amendment to the United States constitution guarantees to the states and their people all powers not granted to the federal government elsewhere in the constitution and reserves to the state and people of Montana certain powers as they were understood at the time that Montana was admitted to statehood in 1889. The guaranty of those powers is a matter of contract between the state and people of Montana and the United States as of the time that the compact with the United States was agreed upon and adopted by Montana and the United States in 1889.
(2) The ninth amendment to the United States constitution guarantees to the people rights not granted in the constitution and reserves to the people of Montana certain rights as they were understood at the time that Montana was admitted to statehood in 1889. The guaranty of those rights is a matter of contract between the state and people of Montana and the United States as of the time that the compact with the United States was agreed upon and adopted by Montana and the United States in 1889.
(3) The regulation of intrastate commerce is vested in the states under the 9th and 10th amendments to the United States constitution, particularly if not expressly preempted by federal law. Congress has not expressly preempted state regulation of intrastate commerce pertaining to the manufacture on an intrastate basis of firearms, firearms accessories, and ammunition.
(4) The second amendment to the United States constitution reserves to the people the right to keep and bear arms as that right was understood at the time that Montana was admitted to statehood in 1889, and the guaranty of the right is a matter of contract between the state and people of Montana and the United States as of the time that the compact with the United States was agreed upon and adopted by Montana and the United States in 1889.
(5) Article II, section 12, of the Montana constitution clearly secures to Montana citizens, and prohibits government interference with, the right of individual Montana citizens to keep and bear arms. This constitutional protection is unchanged from the 1889 Montana constitution, which was approved by congress and the people of Montana, and the right exists as it was understood at the time that the compact with the United States was agreed upon and adopted by Montana and the United States in 1889.
http://data.opi.mt.gov/bills/2009/billhtml/HB0246.htm
So it looks like they are saying if it is manufactured in Montana, and stays in Montana, the U.S. Federal Government cannot restrict your firearms.