Machinery, February 1907
W.L. McLaren, The Manufacture of Shot-guns at the Ithaca Gun Companys Works
https://books.google.com/books?id=AvVFAQAAIAAJ&pg=PA303&lpg The barrels (Krupp-Essen, Cockerill, Twist & Damascus) are all imported; they come in boxes containing 50 pairs each, rough-turned and rough-bored to within .030 inch of finished size.
More evidence that the U.S. doubles makers did NOT source their tubes domestically, at least pre-WWI.
More information here
https://docs.google.com/document/pub?id=17ixogftgITEblNUWtmFBv96ZvgjK6eFell8GsAWd-KI
