A couple caveats, folks....
Unless you're a seasoned ballistic technician with a modern lab at your disposal, DON'T try to develop new loads.
Going from one shotgun primer to another, according to one load book I read recently, can change the pressure in a 1 1/8 oz load 4000 PSI. By itself, that's enough sometimes to turn barrel metal into shrapnel.
Add a guesstimated amount of powder unsuited for the load, and someone has nominated themselves for the Darwin Awards.
OTOH, since these are offered by a reputable company, mayhap there's reliable loading info out there. If so, be sure to follow the recipe exactly.