I am an old west re-enactor and we load all of our own blanks.....except the shotguns. Those we purchase and have used WW Blackpowder and Fiocchi smokless. Those BP's are LOUD!!!

We have messed with loading the shotguns too, and it is just such a pain we buy them instead. However, if you want to try them what has worked for us is loading the shell about 3/4 full with BP and top it off with vermiculite. (can be purchased at Home Depot, Menard's, etc). It compresses easily and is extremely light in weight. It has proven to be the best material to compress the powder in all of our blanks as it is the safest. As mentioned already a card wad in a shot shell is deadly. The vermiculite will come out a disperse in the air.

Dan