I have a beautiful old Griefelt 12 bore hammer gun with .060 and .060 chokes and barrel walls as thick as I have ever seen, just massive. Built in the 1920's with nitro proofed steel barels. Not sure of the intended use, perhaps HIGH flying driven birds. This is the tightest choked gun I have seen. Highly engraved, outstanding wood, apparently a purpose built gun for someone, I would love to know the story.