I worked at a historical society in Pennsylvania and ran into similar difficulties about 8 years ago.  I had a staff member at another museum, who was an expert in weapons and other militaria, offer to help do some basic cataloging of my institution's military collections.  At that time he informed me that we held weapons that we could not legally hold.  From what I remember, he told me there were regulations (Federal perhaps?) that restricted what a private museum could own versus what a "public" (i.e. a state museum) could own.  The items in question had wonderful provenance to the county in which they were held and I was reluctant to dispose of them.  We then made arrangements to "give" the items to a museum that could legally own them and then loan the items back to my institution so we would be in legal compliance.  I found that local officials, though they are well intentioned, really didn't understand the laws/rules regarding weapons as they applied to museums.  I would seek out professionals at museums in your state that have large collections of weapons on display and seek their help in identifying the appropriate rules/laws for museums.  If they can't help they should be able to provide you with some contacts who will help you get through the maze.

Andree Miller
Historic Site Director
The Pearl S. Buck House
Perkasie, PA
215-249-0100 x119
[log in to unmask]