If it is leaking out the back, it isn't related to the level 10 orings. If the velocity(pressure) is turned up too far, it will leak out the back. If it won't fire, then it probably isn't a high velocity issue. A leak out the back is usually a regulator seat oring or a regulator valve pin oring. If the orings are new, then they are probably ok. Make sure the orings and the valve surfaces are clean. Wet the orings with some light synthetic oil when putting them back in place. The oil will lubricate the surface of the oring and allow it to move into place easier. That way it will seal quicker when air is applied.
If the 1.0 carrier leaks with the new oring, try the 0.5 carrier with the same oring. Add a bit of oil to wet the orings. What is the condition of your sear? Wear on the tip could cause leaking out the front because the bolt would sit farther forward and allow the vent hole to be exposed.
Except for the Automag in front, its usually the man behind the equipment that counts.