On a serious note.....I tried replacing shot with rice a few years back, just to have for critter control around my chicken coop. I figured it would also be something the birds would eat. This was before I learned anything about re-loading, and I found out that didnt work. They just made a light 'pop' and barely came out of the barrel. The weight of the shot in the barrel creates resistance and without that weight it dont go BOOM. If you reduce the weight of the shot, I think you would need an appropriately faster powder, maybe a little bit of Bullseye. look in your re-loading book for the very lightest shot loads that you can find, otherwise you might just end up with a little 'popcorn fart'.