[JLA]

Allow me to bring the first fix it question to the board.... I have been tinkering with my father-in-laws bushmaster AR-15. It has developed a condition where it doesnt want to cycle. It will kick the empty out but not chamber a new round. I have thoroughly cleaned the rifle, so dirt and excess residue are out as causes, I have changed the gas piston rings to the one piece design, so no possiblilty of gas blow by due to bad rings. I am getting excessive blast out the side of the bolt upon firing, the bolt will cycle enough to kick the empty free of the action but shortstrokes back into battery. My question is, What else am I overlooking? The only other part to the gas system is a manifold that isnt leaking, and a gas tube that fits snug to the manifold and seals well with the bolt. could the cylinder be worn and letting the gas out around the rings? I need help guys...