"Gun Barrel Industry in Liege"
http://books.google.com/books?id=piEZAAAAYAAJ&pg=PA330&dq 1904
Unless due care is exercised this sleeve can be the cause of great damage to the gun barrel, for, in its various hammering and the reduction of the finished barrel to the proper gauge, parts of this sleeve adhere to the inside of the tube, and the shooter will notice the scaling off of this foreign substance,
which is called splinters. It is not part of the barrel proper, and is the result of carelessness. This happens only with the barrel of inferior make. With the higher grade of barrels the minute examination of the same would invariably reveal this defect.
The barrel is welded and hammered into form in proportion to the outside dimensions, which proportion must be maintained to increase and preserve its strength and flexibility.
The next step is the boring out, straightening, and polishing, the latter being done on an emery stone, which permits of better results than the lathe, inasmuch as it better preserves the proportional thickness throughout, and, the makers say, gives better satisfaction than the lathe.
The straightening is done in a small, vise-like machine, arranged slightly higher than the operator's head. The barrel is placed in this machine while the force is operated through a hand lever. The barrel is focused on a subdued light about 20 feet from the operator, while his eye is placed close to the barrel at the end above his head, which end is gradually brought down until the proper focus is secured. The eye must be accurate to get results, while the work is rapidly done.
