i have a Nikon 6x18x40sf fine cross hair with dot. the side focus knob is a bit stiff to turn any idea what causing this? Scope is on a savage mod 12. scope works fine just the side focus is stiff. Thinking about sending back to Nikon for repair even though I don't like the Reticle. Thought about selling but don't want to sell some one else the problem. Any idea's or suggestions is most welcome thanks.