Apparently, the items found in the house are not actually gun parts but an upgrade part for the Makerbot printer. It just looks almost like gun parts. I’ve read that there are real guns that have been created and were successfully fired in the US. Instead of making things that can be a threat for human, why don’t they just create more practical things like jewellery, iPhone cases or pencil holder? Here are examples of what you can create with 3D printing: Gallery of Cool 3D printed objects.