Thank you Ken. A tech at METL was breaking bolts when I visited. The one barrel that I have which is a candidate for destructive testing is pitted and over-honed Damascus-Twist, but the chamber might be a candidate for testing.
I did find these references to Whitworth, Krupp, and Seimens steel, but need someone smarter to tell me what it all means, and how they compare to 4140.

http://books.google.com/books?id=ycUOAAAAYAAJ&pg=PA614&lpg

http://books.google.com/books?id=czsyAQA...p;q&f=false

https://sites.google.com/a/damascusknowledge.com/www/home