Aridus Industries is still in the process of crowdfunding the production of their Q-DC, a quick detach shell carrier for shotguns. None of the major crowdfunding sites would accept their project because it is a gun part so they are pre-selling product at a discount on their own in order to reach their goals. They also just released a new product for pre-sale that might just make reaching their goal easier.
The Universal Q-DC is base plate unit designed to be used on a wide variety of shotguns. It uses some really tenacious double sided tape to stick to the side of your shotgun. As long as you prep the surface well, you will likely break parts of your shotgun or the Q-DC before it comes off. The Universal Q-DC has relief cuts in areas where pins would commonly be located on the receiver to allow the pins to be removed for cleaning.
This universal version of the Q-DC has already been tested on popular shotguns like the excellent Beretta 1301 and Mossberg 930. Aridus Industries has made a downloadable template available via their website so you can check for fit on your shotgun.
These are being offered at a steep discount during this pre-order. Check them out at Aridus Industries.