Firearms is a modification of Valve Software's computer game, Half-Life. It's a realistic modification of the game, that focuses on teamplay with gameplay altered to the extreme. Oh and did I mention this mod is loaded to the hilt with beautifully detailed firearms.
FACS is designed for quick-changing to your favourite Firearms configuration file.This comes very handy when a bunch of people who are preffering different controls/settings plays FA on a shared computer, like in a cybercafe.