Tuning BSF 55 disassembly help

I have a BSF model 55 I am trying to to strip and it has a scope/sight rail that is attached to the receiver tube with one screw and then I understand it's slotted into the receiver on the back end. I am not sure if the rail needs to be tapped to the front or rear of the receiver to get it off. I don't want to force it and damage it so any help appreciated!