Another option is a used A-Bolt.
That would be a winner but I saw one on Gunsamerica for 1995.If I could find someone that could validate the xtrema 2 shooting slugs I would probably just buy that shotgun. It doesn't have the threaded barrel and tight lockup of a bolt or model 37 but the tang on that barrel is very long and has to make the barrel ultra stable. I hope I don't talk myself into the Xtrema 2
http://www.gunbroker.com/Auction/ViewItem.asp?Item=91714400