Cast hunting bullets should not be hard, simple as that. What Gnoahhh said covers it well. On the other hand, if one has a sense of humor, pure lead that is paper patched does the trick quite well.
That bullet left the muzzle of my 77/44 at ~1600 fps and was recovered from the deer shot at 80 yards. Broke both forelegs, 5 ribs and cut the heart in half. Nothing shot with it ever took a step.
So, how accurate can such things be? 8 shots...