The DeHoff G560-B1 from Kays Engineering (Marshall, MO) is a custom machine designed to form the rifling grooves in gun barrels. The barrel is rotated by a 3-jaw chuck while a rifling button tool is pulled through the barrel by a hydraulic cylinder. The button tool deforms the rifling grooves into the internal bore of the barrel using a swaging process. All the rifling grooves are cold-formed in a single pass.
The G560-B1 can machine barrels from 17 caliber up to 50 caliber, and has a slide travel of 60 inches (1524 mm). It features a pneumatically-operated chuck with programmable “twist rates.”