I've always used hammer/chisel, or a GraverMach. For the Kentucky rifle, the hammer/chisel is most appropriate. The power assisted engraving verges on 'too perfect' for evoking traditional American folk art.
I've never mastered the hand push engraver. I do a little copper plate engraving, for printing purposes, and for that, light cuts are essential, for a deep cut holds too much ink. So I push engrave copper, and that I can do. But for steel and brass, on a sideplate or lock; I prefer the hammer and chisel.
