Masterdude Pump Action Shot Gun (MPASG). I made it a couple months ago and in short, it works but it is weak. It fires three gray connectors at a time and has a removable mag. Since making it I have already taken it apart and have gone to work on other projects. There will not be an I'ble but if anyone for any reason would want to make it or examine how it works, I have put here some images of the internals.
Warning- These K'nex projects may cause harm or injury if misused. Do not point it at people. I am not responsible for damage, injury, or death caused by this instructable. Treat these as potentially dangerous objects.