With 20.7 gr of WSH and the BP-1044, the top of the wad comes 0.84" short of the end of the hull.
The 1 1/8 oz. load of 7 1/2s comes about 0.33" short of the capacity of the wad.
Either I need a MUCH greater volume of powder or I need a shorter hull, AND I still need to add about 1/3" of fiber wad in the shot cup.
If the load works well, why not just cut the cartridges down?
That seems like the most efficient way to go.
I think I need to buy a "modern" 10 gauge to do some testing in