The now-defunct Pancor Inc.'s Jackhammer shotgun enjoys a very special kind of reputation in the general public's consciousness, much like the fabled H&K G11 caseless rifle that was developed around the same time. It's one of those rare kinds of super high-tech, monstrously powerful weapons that gets most of its exposure in gun bunny-friendly films and video games but conversely no attention at all in mass media. Consequently, most people are a bit dubious of any claims that weapons like it actually exist in the real world, much less an exact copy of what they see portrayed in Rogue Spear or Max Payne, able to chew up human bodies like a plastic shredder in the blink of an eye. But that's exactly what the jackhammer was designed to do: to be a bullpup-configured, high capacity riot gun with truly full automatic capabilites.
The weapon measures 787 mm in length and weighs 4.57 kg loaded, corresponding to the approximate size and mass of an AK-47 assault rifle. It is fed by a rotary cylinder magazine (or "cassette," if you feel the need to add a bit of sci-fi flavoring) which cycles through conventional 12-gauge shells at the leisurely rate of four rounds per second. The firing action is remarkably close to that of a revolver's. It consists of an open, "floating" barrel with the cassette mounted behind the action. Gas pressure from a firing cartridge drives the barrel out, whereupon the cassette is revolved to the next chamber and the barrel returns to rejoin the seal with it. Despite being an "automatic" firearm, there is no such system of ejection. Spent rounds are kept in the cassette until manually removed. Naturally, it is also possible to fire single shots, in the event where conservation of ammunition would be a priority -- though exactly why one would want to bring such a weapon to such a situation deserves much closer examination.
There is also the cleverly misnamed "Bear Trap" device, designed to convert the weapon into an anti-personnel booby-trap. The Jackhammer's full load can be blown all at once without manual manipulation on cue from a sensor linked to it, set to respond to either an application or release of pressure. The Bear Trap can alternatively be set to let loose after a designated period of time anywhere between five seconds up to twelve hours. Which would surely add a couple inventive dimensions of sport to just about any otherwise bland form of execution.