Ummm, your information is a bit dated.
From 2013:
https://www.youtube.com/watch?v=IylGx-48TUI
.357 magnum - 2016
https://www.youtube.com/watch?v=1jFjtE7bzeU
.22 - 2020
https://www.youtube.com/watch?v=7RUZsCewg14
double action zigzag revolver - 2022
https://www.youtube.com/watch?v=lWCqpbDhdjk
Springs, barrels and other hardened parts are made of STEEL alloy. Look up steel making. Show me a 3D printer that can produce steel parts.