FX FX maverick cocking rod

When looking through the access hole to remove the pellet probe securement screw you want to set the cocking rod to hold the probe so the screw is slightly forward of center in that access hole. Sounds like your probe was probably slightly too far back. I usually stick an Allen wrench into the screw and apply slight forward pressure to force it front of center and then tighten the locking screws on the cocking rod.