There should be a resource called “junk” which would look like a small trash heap. It should be needed for building junk weapons like the revolver and the pipe shotgun, and other future “junk” weapons, alongside smelted metal and wood and cloth.
The reasoning behind is, the idea of one building even a revolver from pure ore is ridiculous. However, we can assume one can salvage this and that from trash or broken machinery, and put together some crude weapon firing mechanism.

I think it is a good idea. also these weapons should have no recipe. so you will need to guess what the components of this weapon are and how many of them you need.