In reply to Beowulf:
We only had one person with firearms certificate, that seemed to be enough. Getting the gun was hassle, though. The person with the certificate had borrowed it from a friend, but due to airline restrictions nowadays the gun is not allowed to travel in one piece, you have to take some bits out (I forget the right word forf it) So, guess what, some of those bits got lost.
So, we had to hire one out there sort of last minute, but the gun we got was a world war one monstrous thing that was a little faulty, when loading, the cartridges wouldn't quite go in, you had to carefully push it in with your finger. Glad, I never encountered a polar bear....you couldn't really ask him to wait til you fiddled your cartridge into the gun....Also, I would have been devastated to have to shoot one!
Here is a local tour operator in Kulusuk who might be able to help you (address and phone numbers on the webiste)
http://www.eastgreenland.com/database.asp?lang=eng&num=445