#1 is a South African DENEL NS2000 "Neostead" shotgun. It's roughly 27" long with a 24" barrel, 12 gauge, 2.75" chamber. It's reverse pump action, in that you push the slide forward to rotate and unlock the barrel and pull it away from the fixed breech block, then pull it rearward to bring it back into battery. The ejection port is on the bottom of the stock, behind the pistol grip. It has twin tubular magazines sitting parallel on the top of the barrel. Each magazine holds 6 shells. There's a lever at the back of the magazine tube which allows you to quickly and easily select left-tube feed, right-tube feed, or alternating feed. Behind the mag selector is the catch for releasing the mags. They pivot at the front end and are pushed up against the bottom of the carrying handle by a large ribbon spring, exposing the back ends for loading. There are witness holes cut in the tops of the mags to check remaining ammunition. The safety hangs under the gun, inside the trigger guard; forward for fire, back for safe. The manual slide release is located on the bottom of the forend at the front end, and it has blade front and ghost ring rear sights both mounted in the carrying handle.
There is a member here by the screen name of "Kobun" who has one; IIRC he lives in Norway. Obviously, this thing isn't imported to the US. There's nothing inherantly illegal about it, but everyone's afraid that as soon as they reach the US market the ATF will rule them as DDs just like the USAS-12 and Striker-12 shotguns.
Some of the people in those photos have regular ID tags and, as Fly pointed out, their polos say "Firearms Technology Branch". Seeing that room just gives me another reason to hate BATFE.
Would someone tell me what the Hell is up with this carbine? Edit: Nevermind, I figured it out. M3 night rifle missing the optics.