Well, if it was any other pistol, I'd say that you would have to cycle the action manually by pushing the pistol grip forward. Slide stays in place, ejects the spent casing. When you release, the pistol is pushed backward and the slide chambers the next round.

Go here, watch the video, and imagine that the slide is motionless. The only motion comes from pushing the pistol frame back and forth.

However, the company says that the shotgun attachment that Scarab found is single-shot. Which doesn't surprise me; how the Hell are you supposed to fit a 2.5" shotgun shell in the confines of a pistol grip?

It seems like they've modified the pistol into a Beretta-sized break-action shotgun. I'd personally love to know how they did this.