While on the subject of casting brass i would mention i watched a utube video of a guy that melted down a large amount of empty cartridge cases into a solid block then milled a usable tool from the block. Cartridge cases are not pure brass but a alloy that could be put towards decorative pieces. 22rimfire cases are not reusable as are centerfire but mostly free at a lot of ranges.
IIRC, the standard Brass Alloy used in Cartridge cases is called 95-5, 95 percent Copper, 5 percent Zinc, and is considered a Deep Drawing alloy.
Dunno if you could actually burn out the Zinc, and simply add some Tin to the resultant pot, after skimming the dross, to make a Bronze alloy. Or sub in Tin for a replacement of lost Zinc.