Did you try to take of all the pellet probe block ?
Only one screw at the back
The pellet probe block is connected to the cocking lever by a "puzzle piece". The cocking lever has to be in the open position in order to disengage the PP block from the cocking lever at the "puzzle piece". With the cocking lever stuck in the forward -- closed position -- the "puzzle piece" is inaccessible. Hence removing that one screw in the back of the pellet probe block does no good.
I love the term "puzzle piece", gotta' remember that one!