Ryan:
H110 / W296 (the same powder) is really meant for high pressure jacketed bullet loads. I use it in my Marlin Model 1894c carbine in .357 Magnum, but only with 180 grain jacketed bullets. I think you may find if you load those cast bullets (unless they are cast of water-quenched linotype, montype or stereotype), you're going to get a bad case of leading & pi$$-poor accuracy.
For my cast bullets, & mine are water-quenched lino-type & wheel-weight alloy that have a BHN of ~28, I use pistol or shotgun powders. I've had good luck with 452AA & WST with 130 grain RNFPPB bullets (800x was a poor 2nd choice), HS-6 / W540 (same powder) and 158 grain RNPB bullets (800x was also a poor second choice) & Nobel Magnum 6 with 195 grain RNFPPB bullets.
Those bullets you have are not really meant to be pushed so fast (actually, it's not the velocity, it's the elastomeric pressure level of the alloy). Check out the various loading manuals for CAS loads. They're really pretty slow & are meant to replicate the old Black Powder velocity levels.
Not sure if you're using this in a revolver or a rifle, but since I sold all of my handguns ~20 years ago, I can't help you with revolver loads.
Jim