I recently came across the following video of Dave Canterbury (he runs the Pathfinder school in the US) using his single shot 12 gauge as a muzzleloader, and I thought I would share it with you all. I'm not sure how practical it is, but in a survival situation or in the event of a shortage of 12ga shotgun shells (hey, it could happen...just look at the .22 shortage in the US) it might be good knowledge to have stored away in your noggin! 
P.S. I tried using the search function before posting this to see if something similar had been posted before, but my search results came back negative.
P.S. I tried using the search function before posting this to see if something similar had been posted before, but my search results came back negative.