It's a jury-rigged 9mm submachine gun with an improvised bayonet built from scrap metals paired in some places with pieces of tissue and crafted in the workshops of Jane's raiders in Carbon MillTexas in 2208.
The first automatic weapon and a pretty good gun for chapter 1. Unfortunately, the home-made machine gun is overtaken by the SMG found one or two zones later, which does the same damage per shot but its rate of fire is higher.