Laminated

is the term applied to barrels made from compound bars. In twist-barrels, the ribbon is several yards long, about half an inch wide, and thicker at the breech than at the muzzle end. It is heated to redne , wound on the mandrel, then removed and heated to the welding-point slipped over a rod with a shoulder at the lower end. The rod is then dropped vertically several times on a block of metal, which welds the spiral edges together. This is called jumping . The welding is completed by hammering. Rifle-barrels and the cheaper kinds of shot-gun barrels are made directly from the skelp , which is pa ed between rollers, which first bend the plate longitudinally and afterwards convert it into a tube. The tube is then heated to a welding heat, a mandrel is pushed into it, and it is pa ed through the welding rolls, which weld the edges and at the same time taper and lengthen the tube. The boring and turning are done in lathes.