Yes, you could.
However, it would be just as easy to have an investment casting company 3D-print the mold for you, with one of their wax or green sand printers. Or... just have them cast the receivers.
I'm all for doing something myself, and I do see myself using 3D printing for prototyping very soon. ...but we're not quite to the point that receivers can be affordably printed in a usable state.
"Such is the strange way that man works -- first he virtually destroys a species and then does everything in his power to restore it."