i imagine its like a cartridge that houses stacked electronically primed projectiles down a (disposable?) barrel, all self contained in a single unit. funnily enough, that sort of thing technically gains slight increases to accuracy, in flight stability, and projectile velocity the further into the cartridge you go.
Based on the design I'd guess something of a disposable one-shot railgun. Railguns do have inherent flaw of the driving barrel becoming unusable from the forces applied to the barrel, so making it one-use only prevents misfiring and the whole thing blowing up on your face.