I agree. I think the 3D printed units were more of a "can it be done" experiment. Even they were not 100% 3D printed. Certain areas of a firearm generated too much heat and force for the plastics available in an affordable 3D printer.
On an undisclosed base, in an undisclosed foreign country was bunker similiar to the one listed. We were drinking buddies with the range master who was responsible for making sure that none of the ammo was past the expiration date. When it was, he was responsible for destroying it. The reg stated he had to have two witnesses to the destruction and it had to be documented and signed off by all. A destruction method was strangely absent from the directive. So about 4 times a year (once per quarter). a crate or 2 of ammo was past its prime. The 3 of us with M-16s on full auto for a couple of hours of fun was the method of destruction.