alloy, straight wheel weights,
Loads 8.5 - 10.0 Unique, 18.0 - 21.0 2400
I used to load the 8.5 unique with out a gas check and add a pinch of poly fiber for the wife to shoot silhouettes with. Looked like she shot a "puff ball weed"
I would suggest you mike or slug the cylinder throats and hopefully your mold will throw bullets slightly larger {.001} that the throat dia. and try to size to that dia.