This is Vriess Hero shotgun from Alien Resurrection. It is one of two guns that are Concealed in his wheelchair. He can be seen to assemble the gun when he meets the other on comming out of the lift. It is then handed to Christie who later uses it in the under water sequence to blow up the facehugger eggs. The stock pulls out of the body of the gun and is made from aluminium. Just below this there is a 'back hatch' that opens up to reviel where you were perhaps supposed to load the cartridges. The trigger moves as does the Pump-handle which is spring loaded. The whole of the barrel assembly is made from metal.
