Twist is the term applied to coiled barrels. The iron or steel is made into a ribbon, which is wound spirally around a mandrel and welded.
Stub-twist is stub-iron coiled.
Wire-twist is made by welding iron and steel bars together, or two qualities of iron, and drawing the compound bar into a ribbon, which is coiled as before described. The term is specially applied to coiled barrels made from small ribbons.
Damascus iron is made by twisting compound bars of steel and iron, welding several of the twisted bars together and forming a ribbon from the mass.
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 redness, 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 passed 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 passed 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.
Gun-carriage. See [Carriage].
Gun-carriage, Barbette. See [Barbette Carriage].
Gun-carriage, Field. See [Field-carriage].