I have a Super Blackhawk Hunter model. I've never got good gpoups with the 180gr bullets. The Two loads I use for 99% of my shooting in this gun are as follows. 250gr cast 429421 over 9.0 grains of unique, these average 1100 fps and are accurate @ 1 1/4" @ 25 yds for 12 shots, twice around the cyl.. My hunting load consists of a 429244GC over 21.5 grs. of 2400. This is a very hot load with the newer lots of 2400 so start at 19.5 or 20 grs and work up.5 grs at a time. My cases fall out and don't show any signs of high pressure, but that's just my gun. With the lube and the gas check this bullet weighs 265 grs in my alloy. With the above load it averages 1408 fps and shoots 1 1/8 for 12 rnds. 240 gr Hornady XTP's over 23.5 grs of Win.296 shoot 1 1/4" but I no longer use any jacketed bullets in either of my .44 mags. If I had to buy cast bullets I'd get the 260gr WFN avaible from several comm. casters.
Hope this helps.
Dave