The best sniper scopes improve image quality, give added range with hits on target and allow for parallax, elevation and windage. Increased magnification provides a shooter with more accuracy.

Long-distance shots require variable optics allowing the marksman to adjust the magnification for their requirements.

One of the most up to date and best scopes is the Nightforce Advanced Tactical Riflescope which is used by the US military. 

Another superb sniper scope is the Vortex Viper HS LR 6-24x50 scope. It is a very robust scope with many features and crystal clear vision.

It features FFP, (first focal plane which gives highly accurate ranging, is supremely weatherproof and the crosshair withstands recoil magnificently. 

The Leupold VX-2 4-12×40 scope is another excellent scope which is weatherproof and works well in low-light conditions. It has an objective parallax adjustment from short-range to infinity, and it increases light transmission by 94%, meaning that it can shoot in ultra low-light environments. 

The Athlon Argos BTR 8-34×56 FFP has an easy-to-use AMPR FFP IR MIL reticle and a fully multicoated optic and as you would expect its weatherproof.

Thriller writers also have a great interest in sniper scopes as they often feature in their novels, being used by killers, armed forces or SWOT teams. One of the finest assassin novels ever witten was Frederick Forsyth's – The Day of the Jackal. A well constructed, intelligent novel with great detail.