smoothshooter
50 Cal.
I’ve done both powder wad ball and a few times the wad on top of the ball. One issue for me is I use homemade lubricated wadS and I suspect if loaded between the ball and powder the wad may contaminate The powder if left loaded for an extended period.
If the wad lube is not runny or oily it will not have any noticeable effect on the powder. I have experimented around with this issue several times over the years. I will admit that I have not checked the results with a chronograph, but recoil, noise, accuracy, and point of impact were as normal when left loaded in clean chambers for weeks and months at a time in pretty hot weather.
Am not convinced that a wad works as much of a gas seal, so I have used undersized wads In normal loading, and in paper cartridges because they fit in the tubes better. Everything still works fine. Even when I have used square wads just to see what would happen.