Steve, a firearms manufacturer, uses the hummer forging process for rifling the barrel of a gun. Which of the following statements describes the correct technique used by Steve? Group of answer choices Steve rifles the barrel by having one or two grooves, at a time, cut into the surface with steel hook cutters. Steve uses a series of concentric steel rings to insert it into the barrel which simultaneously cuts all grooves into the barrel. Steve inserts a mandrel into a slightly oversized bore, and the barrel is compressed with hammering into the mandrel's form. Steve uses a steel plug impressed with the desired number of grooves and forces it under pressure through the barrel