i love how you guys assume the gun is plastic.
you can make steel guns using 3d printers, the materials exist for it.
You can create molds using 3D printers and make diecast items, sure, but that's far beyond using a 3D printer for basic stuff. You'll be spending out the ass.
Tony's argument isn't valid considering the plastics which are "as strong as steel" (which isn't true considering polymers aren't the same as steel) can't be used effectively with a basic 3D printer. Again, you can get into casting, but that requires a lot more experience and money than owning a 3D printer.