"A cnc machine is cheaper.You nan be just as good at making lowers with a 3 axis mill and Solid Works.Really.
You can but an AR lower for $125.A good one. "
We are just talking about something like a lower receiver here. We are probably a decade from printing a fully functional firearm. I don't think it would be any weaker than the injection molded lowers on the market.
You can rent a 3d printer capable of printing a lower from an outfit in the UK for something like $500 a month. A great many sources indicate the parts are about that if you know how to put one together. The plastic inputs are dirt cheap. Electric and such is probably significant, but I haven't found any numbers on it. No idea what sort of cleaning is necessary.
I am unaware of any place I can take a downloaded blue print on a USB drive, plug it into a computer and for a nominal fee get a machined lower in 15 minutes. This really will be a game changer.