its eigther a oil finish on a steel frame or its jet blacked, both are used in gun smithing. the oil finish simply gets burned onto the metal at a certain temperature, the jet black is a acid finish. or its simply waxed with a metal finish wax like old black smith garden fences used to be.
its eigther a oil finish on a steel frame or its jet blacked, both are used in gun smithing. the oil finish simply gets burned onto the metal at a certain temperature, the jet black is a acid finish. or its simply waxed with a metal finish wax like old black smith garden fences used to be.