force needed when sliding safety to off...

[edgarspencer]

Dean describes a binding of the actual rocker lever which connects to the slide button, but were that the situation in the OP's gun, the button would be stiff, if not entirely bound up ALL the time.
The problem he is having is that the button is very stiff to push forward (which is also pushing the round rod forward, inside the hole in the stock) but then moves freely back and forth, because the offending rod is now "out of the way".
If the tang screw is over tightened, as Dean is describing, the safety button is either stuck because the rod is tight upon the sears, or if in the off position, will not go fully on, because it is hitting the edge of the sear.