Just saw this on Arnies, I'm just gonna rip the text:
Coming soon from Madbull, quite possibly the best solution I've ever seen for a reliable and durable airsoft shell ejecting shotgun.
Madbull's solution? Don't try to reinvent the shotgun, reinvent the shell!
Shotshell CO2 Chrono
Loading & Firing Shell
As you can see, Madbull's idea was a simple yet brilliant one. Instead of trying to make a reliable airsoft shell ejecting shotgun they decided to make shells that will fit in a real 12ga shotgun but instead of gun powder and buckshot they hold five 6mm BBs and are filled with CO2/Gas in the back ala Tanaka shells. When the firing pin in the shotgun drops the gas release on the back of the shell is hit and the shell fires.
With this system you would not have to worry about cheap poorly built pot metal internals failing (which is a major concern with every airsoft shell ejecting shotgun) and most people who are into shotguns already own a real 12ga so all you'd have to buy are these training shells to get your airsoft shotgun fix.
looks cool, high fps if you're using CO2, little crazy for me though. I don't feel too safe with a guy showing up to a game with a real shotgun. Sure he's using the madbull shells, but its still a bit unnerving knowing its a real gun...