The Vectan A0 powder meters very easily and performs verygood in my 223. It has a burning rate close to Blue Dot.. Their loading manual shows a cast load for 222 Remington and 308 Winchester. It is bulkier than Unique and fills case better.
222 Rem, 49gr Lyman, SR primer, AO powder, 5.4gr 1839 fps, 8.5gr 2307 fps 308Win, 150gr Lyman, LR primer, AO powder, 7.7gr 1192 fps, 12.3gr 1506 fps ...