http://en.wikipedia.org/wiki/LWRC_Infantry_Automatic_Rifle
http://www.lwrifles.com/Technology/tabid/55/Default.aspx
These 2 links might give you a little bit information, especially the little flash clip at the bottom of the technology section of the LWRC website. It kinda show you the difference between the LWRC short stroke piston driven system and the regular old skool direct gas system. The hot gas ios released in the middle of the gas tube instead of going all the way back to the chamber.
