Close-up of Ruger parallax
adjustment
The parallax adjusting ring can be clearly seen in this view. It is vital for target shooting purposes to be able to adjust for parallax at different ranges, sights without this facility are usually preset to be accurate at 100 yards. A sight which is set for 100 yards will typically have about 1 inch of movement error at 25 yards and is useless for accurate target shooting. This sight can be set at all distances between 10 metres and infinity. Note that parallax, which is the apparent shift in position of a viewed object attributable to the difference between two separate and distinct points of view, is not to be confused with focussing. This scope adjusts for focussing and magnification at the eyepiece end.
