200gr Bloodline is 40cal
To shoot sabotless 458s requires a full form sizing die or mutli step sizing down to around .451. Most of us shooting sabotless go straight to a .451 or .452 bullet and a adjustable smooth sizing die. Parker BEs for example are .451 and often fit the CVA 45/70 barrels without sizing.
You dont know for sure until you try them in your barrel. Being just .0005 over could be too much to load easily.