From the back of the book
Big Bang is an open-ended series of reference books designed for avid players of roleplaying games, especially in the modern and near future genres. Each volume presents factual data and information on a number of weapons, including details of the weapon’s history, along with statistics allowing immediate use in a number game systems. The factual, real world data can be used to easily adapt the presented weapons to a wide range of game systems.
Mini-Bang 2 contains rules and descriptions for the various incarnations of the Special Purpose Infantry Weapon, none of which ever saw production.