Thank you for your reply, since I made my call for help in the problems with my M-4, I took it apart, cleaned, including both gas pistons and assembled using Break Free CLP as my lubricant. The gun runs on everything I feed it now including Wal-Mart $20.00 a hundred specials. Needless to say I am very happy now and have 100% confidence that my M-4 will run when needed.