Considering the low melting point of brass, the fact that there are already metalworking tools/stations in game, and the east of actually casting it due to its properties while liquid I think it makes perfect sense.
As for casting it into new casings of the desired size, that probably wouldn’t be possible because cartridge brass is drawn with the upper portion being heat treated to soften it and the lower portion left work hardened from the drawing process. I could see using it in place of copper tubing for handloading though. It would finally make those thousands of spent shells worth something.
What about cast aluminium cases? After all you can heat treat aluminium to harden it so it might be possible. And it would make empty aluminium cans more valuable as well! Downside is you couldn’t reload aluminium casings*, you’d have to melt them down and recast them.
*Note: While it is TECHNICALLY possible to reload aluminium casings I’ve yet to meet anyone that reloads (even the super serious guys) try it AND be willing to actually fire it. Aluminium cases are pretty much a one and done deal. That also assumes you can salvage enough aluminium cases in good enough shape to reload which generally doesn’t happen.
