>>5945I don't know if metal printing/hardening could ever be economically feasible for any hobbyist, the energy requirements would have to be enormous.
I think people tend to forget that guns are pretty oldass technology that you don't really need any high-tech industrial equipment to make. Guns were handforged and handbored for hundreds of years before modern industry developed and now it's even easier to make one - quality steel is plentiful and cheap, you can use simple small forge and hammer for shaping/hardening, power tools for cutting/drilling, arc welder for joining parts, etc.