Algodoo

Drag the shell in and drag it into the hole created. the box on the left can be drug to the right to close it
Pull the trigger and it shoots....
when you are putting another shell in, make sure the trigger is to the left a little past the box. If you do it correctly the shell should fall out of the bottom if not, you can drag it out have fun and comment any problems or anything i should to to fix it... or possibly make it better
Have fun