All of these are "required reading" Tom
The Double Gun & Single Shot Journal "Finding Out For Myself" by Sherman Bell Vol 17: Issue 3 (Autumn 2006) p. 12, Vol 17: Issue 4 (Winter 2006) p. 28, and Vol 20: Issue 3 (Autumn 2009) p. 108
And BTW
Experts on Guns and Shooting George Teasdale Teasdale-Buckell 1900
http://books.google.com/books?id=4xRmHkr7Lp8C
On the subject of steel v. Damascus, Mr Stephen Grant is very clear, and much prefers Damascus for hard working guns. He related an anecdote of one of his patrons, whose keeper stupidly put a 12-bore cartridge into his master’s gun without knowing that he had previously inserted a 20-case, which had stuffed up the barrel. Fortunately,
no burst occurred, but a big bulge, which, however, Mr Grant hammered down, and the gun is now as good as ever.