It's really about RPMs. Round balls need less RPMs to stabilize than bullets which are longer than their diameter. Since the twist rate is not variable without buying another barrel, the other way to control RPM is to vary the velocity of the projectile. Reducing the powder charge slows both the velocity and the rate of spin. Unfortunately for the hunter, energy falls off dramatically as velocity is reduced. If you try conicals, you have control over velocity (powder charge) and bullet length (weight) to achieve the ideal combination of energy and accuracy. Have fun experimenting.