The Calico Light Weapons (CLWS) group, a child of the 1980s, made a lot of interesting helical magazine designed guns, and MAC tests the M900 for posterity.
With a 50 shot (standard) and 100 shot (optional) magazine, the blow-back action M900 was an uber neat gun when it was first produced in the waning era of the Reagan years. Weighing just 3.7-pounds unloaded with the benefit of a 16-inch barrel, these gnarly compact guns soon earned the wrath of the Federal Assault Weapons Ban due to their large magazine capacity during the Clinton years and production sputtered until they were reintroduced in 2007.
Their futuristic designs earned CLWS pistols and carbines a spot in films ranging from Star Trek to Total Recall and The Running Man, though not one in a lot of gun racks.
Still, they are one of the most radical designs of the MTV generation (back when they played music) as MAC verifies, although loading those mags were a bitch.