The best list is maintained by NH Fish and Game
Two sites that do a great job of summarizing the gun laws in NH
Thinking about taking a gun down to Massachusetts? Read this first!
Check the prices online and possibly purchase online. Online gun purchases will be delivered to a local licensed firearms dealer who will only charge you for the federal background check. If you are in the military or law enforcement you can often get a discount. Check the following sites:
http://www.gunbroker.com/ auction site
Great dealer for transfers: http://www.jrsgunsmithing.com/
You can always try writing the manufacture or checking their website if they are still in business. This link has many of the manuals