This 3-D printing thing apparently started back in the ‘90s. I worked for an aerospace company that bought one of these machines early on. The purpose was to “proof” part designs by printing the part out and examining it and its functionality. The material that the printed part was composed of was certainly not substantial enough to permit its use as a genuine part. Gun barrels are typically forged steel. I cannot imagine a printed gun barrel having the strength required to withstand the explosive discharge of a bullet. Perhaps there is something that I am not understanding here. Please correct me if I am wrong.
Search the internet for videos on “Metal Sintering”.
It’s the next generation 3D priting method.
I believe it is possible to make a plastic barrel that withstands the pressure. It just has to be thick enough. Due to the required thicknesses, any firearm made from plastic will likely be heavier/larger than an equivalent made from metal.
The only issue is the bullets will slowly wear down the barrel until the pressure becomes too low. With steel inserts, I have no doubt that a semi-auto firearm is possible. Some plastics can withstand high temperatures so a full-auto may even be possible.
There is no need to print a barrel — that can be bought without legal constraints. The only part of the multi-part gun system which is “the firearm” is the lower receiver. That is not exposed to the strong explosive forces that the chamber or barrel see. In fact, AK-47 lowers are often made by bending light-gage sheet steel.
You’re going to start seeing more and more stuff made with 3D printers.
GE to mass-produce critical jet engine part use 3D printing
Thick, heavy, dense ABS plastic. 22 long rifle.
Capable of just a few shots before it malfunctions.
But it’s a start.