I've just bought a used New Hermes engraving machine (Model GM, table top model, diamond drag) in hopes of doing caliber marking on barrels. Could any of you folks who currently use one of these to mark barrels give me some tips on jigging up a barrel or barreled action in the vise? I don't recall seeing any pictures or descriptions of this, although I've seen several say that they do use a similar machine. I've got an idea or two on how this might be done, but I'd like to hear or see what you more experienced folks have come up with.. thanks.