FYI:
There is a guy on YouTube that loads shotshells in a regular shotgun like a muzzle loader..!!!!
He cut a high brass shell right at the base of the brass to plastic off.
Then reprimmed it and stuck it in the chamber, then poured the powder down the barrel with various pieced rags, paper or wads, then added shot and a final wad to hold it all in.....

Shot it just like a regular shot shell.....????
I never tried this,....!!!
Don2