Quoted:
I'm a resident of montana living in Washington to attend college. At the moment I'm trying to purchase a long gun. Due to Montana law apparently Washington FFLs can't sell to me.I also do not want to get a WA state drivers license as I don't know how this would effect my vehicle registration and insurence. Which leaves me 3 options. Cancel my purchase, Try to find a dealer in Idaho that will be willing to facilitate the transfer. or go the full distance and return to montana to pick up the rifle (would the Montana FFL raise a stink about my primary address being in WA even though legally I'm an MT resident?) So which option should I pick or is there another alternative route to go? Also I still maintain and address in montana

Quoted:
thats what I thought till today and apparently montana has this law on the books.

Purchase of Firearms in Contiguous States

45-8-341. Purchase of rifle or shotgun in contiguous state by Montana resident. Residents of Montana may purchase any rifle or rifles and shotgun or shotguns in a state contiguous to Montana, provided that such residents conform to the applicable provisions of the federal Gun Control Act of 1968 and regulations thereunder, as administered by the United States secretary of the treasury, and provided further that such residents conform to the provisions of law applicable to such purchase in Montana and in the state in which the purchase is made.

taken from http://www.mtssa.org/mtlaws.phtml?code=45-8-341%2C+342+M.C.A.