www.madmaxmovies.com

Could the Bullet Farm produce shotgun shells in the post-apocalyptic world of Furiosa? I am aware it had molten metal capabilities to produce bullets and cartridges. Would the "exteriors" of shotgun shells be difficult to produce in a post-apocalyptic environment?

Were the shotgun shells Praetorian Jack received produced at the Bullet Farm or were they pre-Collapse stock?

I wouldn't say they could produce new shotgun shells, but they could be easily recycled.

Here's how:
https://www.youtube.com/watch?v=WTmaMAPguzs

Easiest way would be to recycle plastic hulls. When they run out of recyclable hulls, they could make full brass hulls they did in the days before paper and plastic hulls.