Scampi-There is no commercial bore cleaner that will strip nickel in minutes. Even industrial nickel stripping solutions take 30 minutes plus.
My bet is that the nickel is only discolored. A gentle wiping with Simichrome polish should brighten it right up.
I sent photo to Ruger and they advised they could not help. I had a tube of FLITZ (metal,plastic polish) that was known to clear headlights, and I heard good reviews on line for guns. So while watching war movies I got my gun slide back to new condition! Thank you Thank you!