Range Mapper

I am trying to automate the movement of a gun barrel, as the Slide of the handgun moves back.

Basically when the “slide” moves back, I want the barrel to slightly move back in the Z and Y axis, and rotate slightly. I’ve almost got it, but at a certain point I want the barrel to stop rotating. I’m having a difficult time with the range mapper, and hoping it can be cleared up.

Thanks!
Matt