While I feel comfortable shooting NfB in my guns, I have not shot duplex loads. My focus has been reasonable accuracy and not exceeding reported BP velocities.

I believe that the initial push for duplex loading was cleaner shooting and adding "umph" to black powder loads to reach the velocities the cartridges were suppose to get.

I know some people have loaded and successfully shot Triple 7 in BPCR because they could not get listed velocities using 2F black powder.

Has anyone on this forum successfully used a black powder substitute and if so, what were the results?