I have a fair bit of experience with W748 in cast. W748 requires a fair bit of pressure to get a consistent burn. Once you get there you probably have a fast accelerating load that stresses a cast boolit and requires a hard alloy and short nose to prevent slump.
While filler can help reduce loads a bit, dacron and fine ball powder is not a great combo for hunting, as the powder will migrate into the filler area very easily, if you tend to move or climb while hunting.
Also W748 is infamous for being temperature sensitive.
Accurate loads can be found with W748 and cast boolits, particularly with heavier for bore weights. It's just that the windows for accuracy are small, and can shift with temperature. The velocity for accuracy windows also may not match your alloy's and lube's abilities.