After some initial testing with Jim Shockey Gold that produced some very good groups, I am having some issues. For some reason, the point of impact varies vertically with this powder. I originaly thought there was something wrong with the scope, but after a lot of range time and experimentation have determined that the gun will not hold zero from day-to-day and week-to-week with this powder. It moves up and down over about a 6" spread. Went back to the old Pyrodex pellet load that always shoots to the same spot. Anyone else experience wandering zero with the APP/Shockey Gold powders?