Orrrrrrrrrrrr,
You guys could ask Kurt of KKF (Kurts Kustom Firearms) if you could buy his ar15 gas piston system.
KKF
"Pictured above is the new KKF M9EvoM4 , This new gas system for the M16/M4/AR15 family of weapons increases reliability, runs cleaner with no barrel gasses bled back...