Originally Posted by bullet111
Where is this middle o-ring in the firing chamber you speak of; and also the 16/70 buna on the nox?
Inside the fire chamber there are 3 o-rings. the one in the middle is the one you should change. It's a urethane 17/70. And yes the buna 16/70 is the black one on the Nox bolt. There is a bumper and the sail o-ring. the one you want to change is the rear one, the sail o-ring.