Not 100 % sure but I think they aren't the same. I think its down to the bolt stop and the fact that the xe is bolt out back so the firing can is different. For example the techt level 7 comes In ion/sp8, xe and epiphany flavours.
EDIT. Actually I'm talking crap, i think the stock bolt is the same. Techt have different models because of the different bolt stop. Leak down barrel could be faulty bolt o-ring, bolt stop o_ring or a nearly play battery. When you gas up does the bolt move forward and then leak?