Thanks for the useful info800 X behind a 125 grain bullet seems to be bested only by the old DuPont SR 4756. The velocities that you got with the 800 X are believable.
For info, on the next hammer that you bob if you do not add any weight back you will have a harder hammer strike.
The hammer will move faster and the impact energy goes up as the square of the velocity.
For example, in our Red Hawk bowling pin guns we normally reduce the weight of the hammer by one half. Granted the primer of choice is the Federal Large Pistol which has a very soft cup but when they aren’t available the light hammer sets off other ones about as well as long as they are hard seated.