You could be right about it needing cleaning. The outside was a little grubby.
What is the best way to clean one? I have a variety of rods, patches, brushes and boresnakes for my rimfires, centerfires and shotguns but nothing specifically for an airgun and not in a .177 caliber.
Also, out of interest why would you not want a CFX that reached the 1000fps that it is advertized as?