When dry firing, one of my rifles,winchester type action) makes my scopes reticle appear to 'jump' in random directions. Scope base and rings were removed and re-installed to verify tightness. I tried another scope, to make sure it wasn't the brand new leupold Mk4 scope and it did the same thing. Neither of my other rifle/scope combo's do this, and am now wondering if it's possibly just something common to this type of action,winchester)? Never had one before. Read about it being natural point of aim, or shooter error....but I put it in a large bench vise to eliminate the shooter variable, and it still does it. Trigger is just under 2 pounds. Anyone ever noticed this jump before? solution?