Early days to now
Riflescopes have been used in one form or another since the middle of the 19th century. They offered a basic optic, not particularly reliable and with low magnification, but generally better than a lot of the iron sights available at the time. Since that time, scopes have transformed into the versatile and reliable instruments with which we are familiar today. Coated optics, large objective lenses, variable magnification, complex reticles and parallax adjustment are some of the many attributes of modern riflescopes found in gunstores today. As optics got progressively better, magnification became greater, creating problems of its own. Heat mirage, parallax and a huge reduction in field of view became factors to consider.
Inexperienced users of scopes found it hard to transition from open sights, with the reticle disappearing constantly into a black hole until they established a firm cheekweld to the stock, thereby maintaining the sighting eye in the correct place to achieve a solid sight picture. And that was just with low powered scopes of 4x and 6x magnification. When confronted with optics of greater magnification, the situation became worse, with critical eye relief and a small field of view adding to their woes.
Scopes of greater magnification are an acquired taste. They can be hard on the eyes, the target can be hard to find due to the small field of view, and eye relief, which is usually generous in lower powered scopes, can become a problem in high powered scopes, having a short eye relief with a narrow usable depth.
Most shooters, when asked, will state that the biggest advantage of a scope over open sights is the magnification. Though useful, this is not the biggest advantage of a scope. The biggest advantage is the placement of the target and the sights into the same focal plane. Let me explain. When you are looking at a target through open sights, you are trying to focus on three things, the target, the foresight and the rear sight. Looking through a scope, you see only the target with the crosshairs superimposed and, when properly adjusted, no matter where you place your eye, the crosshairs remain on the same point on the target.
Will you shoot smaller groups with a larger magnification scope? No, not necessarily. The eye automaticaly centres the reticle on the target. If the target is a circle, then the crosshairs can be placed on the centre of the target with very little error due to the eyes ability to pick up any error to a quite accurate degree.
These days, we find that people generally overscope, meaning they buy scopes with vastly more magnification than is needed to accomplish the task at hand. The price is paid in weight, bulk, critical eye relief, and field of view. Just remember, you only have to see the animal’s head, not it’s eyelashes!