This video is awesome. It's a dream come true. Somebody built the M41A pulse rifle from the movie "Aliens."
As Cpl. Hicks describes it in the film, it's a pulse rifle "ten millimeter with over-and-under thirty millimeter pump action grenade launcher." This replica/recreation has a 9mm submachine gun with a 12 gauge under-barrel shotgun. Not exactly a grenade launcher, but it's close.