I found something interesting on page 117 of the March/April 2007 edition of American Handgunner. (that's right, 2007. I'm a little behind in my reading)
It shows a photo of a 12 ga. shotgun called the "HouseGun". What's peculiar about it is the 18" barrel that flares out to a muzzle diameter of THREE INCHES.
I guess this really opens up the pattern quickly.They call it the modern day Blunderbuss and it's supposed to be really loud too. There's a web address of www.housegun.com, but I couldn't find anything about it at that site. Anyone have any first hand knowledge of these things?