That's not what I was referring to though. I was talking about how detecting the EURion constellation causes Photoshop and printers to not work. I do not know

That's not what I was referring to though. I was talking about how detecting the EURion constellation causes Photoshop and printers to not work. I do not know how guns are manufactured, but from the comments in this and earlier discussions of the story, I assumed that there are parts with common characteristics. As a result, and unless the resulting 3D models are too many, or if they would result in false positives with legitimate applications, you could require that 3D printers and CAD software refuse to work with them. Based on the couple of comments below, however, it seems that my assumption that there is a sufficiently common part among firearms is wrong, so I'll leave further comments to the experts.