I've heard that many newer Italian, Spanish among other guns are "roll engraved."
I am trying to perceive how a "roller" with a reverse image could possibly follow all the curves and flats of a SxS or O/U shotgun receiver and impress an image into a metal surface.
Is there some part of the process that I'm missing?
I understand hand engraving, chasing, laser etching, acid etching, photo etching, etc.
Could someone please explain or use images to help me understand the process.
Thanks in advance.

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