AW&ST just had an article on AM (additive manufacturing). The first baby steps are being taken now. The issue is with the material properties of the items printed. It started with realitively weak resins. Now they can make more durable items, including the gun.

I guess the real question, long term, will be the cost of the machines. Will it become cheap enough that everyone will have a machine or will they be too expensive where only speciality manufactures will have them.