thank you for your wisdom. I bought the gun used, it is a WPA commando ser.001000 it appears to be in great condition. I am shooting fed. 223/5.56 ammo new ammo. I broke the weapon down and cleaned and lubed it thouroughly. I tried firing one rd at a time, the bolt would hit the shell be extracted every time before it could abe completely extracted. I have tried all I know need more of your wisdom. thank you grizz300