Thank you for starting this thread. A couple years ago I bought a box lot containing several old bullet molds at an auction and one of them was a sugarloaf mold, but I didn't know what to call it at the time, and had forgotten about it until seeing this thread. Quite frankly, I didn't know what it was for: Fishing weights and "swan" shot both crossed my mind but since it wasn't round or made for typical conicals, I just wasn't sure. It is a large, hexagonal brass dual cavity mold without handles, though it once had removable handles and there are two holes tapped for small machine thread screws on each side. Both cavities are teardrops and the mold has CAL .312 stamped on it, which looks about right. I'll have to rig up some handles and try casting a few to see what they weigh in at, next time I set up to cast some lead.
I have a mule ear squirrel gun, about that size, but they would probably be too tight with a patch.
Does anyone know if these were fired with patches, just like round balls? I would guess they would take a special tip on the ramrod for the point, whether seated on a patch or any other way.