Very cool! I am going to try this!
that sounds more realistic than the toilet paper roll/ ballon method. I wonder if a condom would work better than a balloon....after you TontoA lil different way is to use a small soda bottle, and remove the top just before the sides go to the label, discard the bottom and save the mouth cone you have created, then use heavy duty kitchen gloves and remove a finger and place over the threaded end of the bottle mouth, secure with twine or electrical tape wrapped around the threads on the mouth. it will fire bb's and 5/16 shot suprisingly fast. I used to make them when i was a kid. Take care. Scary