Every rifle is an individual. What shoots well in one rifle may not shoot well in another. Twist rate, rifling depth, width of lands and grooves, even the amount of polish in the bore will change the way each bullet will shoot. Generally the magnum loads only work with sabots. Conicals have a habit of stripping if the load is too heavy. The most important thing is to work up an accurate powder/bullet combo. The selling point of the magnum loads is velocity. Everybody wants you to be able to shoot like Quigly without having to adjust for bullet drop. Modest charges can be very lethal. Remember, guides for dangerous game often rely on a 45-70. That name stood for 45cal with 70gr blackpowder in the cartridge. I don't know too many people that claim the 45-70 lacks effectiveness.