If you’ve just bought a fancy new rifle and you need a new scope, or you’ve decided you want to put a scope on top of your rifle, you need to understand all the different models and styles available today.
The first thing to understand when choosing the right scope is how a scope works. A scope is a metal tube that encases a series of coated glass lenses.
This allows the target to be viewed on the same focal plane as the sights. Rather than trying to keep the rear sight and front sight and the target all in focus all at the same time, everything is in focus together and if you add magnification, you have an almost perfect system for sighting.
Here are some of the terms used by the optic industry and what they mean for you.
Specifications of a scope are usually stated as: 3-9x40mm, or 4x32mm, or some variation of numbers. The numbers before the ‘x’ refer to the magnification and this can be a fixed number (ie, 4), or a variable number, (ie. 3-9). Whatever that number, it means your target will appear that many times closer than it actually is.
The number after the ‘x’ refers to the diameter of the objective lens, expressed in millimeters.
Scopes are either fixed-power or variable-power. Fixed power scopes are permanently set at a given level of magnification, but variable-power scopes allow for adjustment.
In the past, variable-power scopes weren’t as durable as fixed-power scopes and gained a bad reputation from a lot of hunters. But, today there are so many advances in technology as well as exhaustive training by manufacturers, that most variable-power scopes are just as rugged as fixed-power scopes.
It is hard to beat the versatility of of a variable-scope. Variables in the 2-7x, 3-9x, or 2.5-10x are most popular for hunting big game and fixed powers of 4x or 6x are more popular with hunters who still prefer the simplicity of a fixed-power scope.
Variable power scope allows you to crank up the magnification to a higher setting if you find yourself needing to take a long shot and yet keep the scope on a low setting whenever you encounter game up close or moving.
When it comes to the size of the scope’s objective lens, the bigger it is, the larger the field of view (FOV) will be at any given magnification setting.
Depending on the coatings on the lenses, the brighter the scope will be. This is a major advantage scopes have over iron sights.
Higher quality scopes are able to gather all available light into the scope and utilises it in such a way that you can actually see better during low-light conditions than with the naked eye.
The key here, is high-quality! What makes a high quality scope? Special coatings are applied to the surface of a lens to reduce glare and the amount of light lost during the transmission of the target to your eye. The quality, number and position of these coatings determine how much light is transmitted. Here are your options:
– coated – a single layer is applied to at least one lens
– fully coated – a single layer is applied to all air-to-glass surfaces
– multi-coated – multiple layers are applied to a least one lens surface
– fully multi-coated – multiple layers are applied to all air-to-glass surfaces
The more coatings, usually translates into a more expensive and high-quality scope. Most of the high-quality scopes are also waterproof, fogproof, and shockproof. These are not cheap! As in most optics, you do get what you pay for.
Rifle Scope Anatomy and Terminology
The metal assembly that holds the Ocular lens and is attached to the eye-bell
The lens closest to your eye
The distance from your eye to the ocular lens when you can see the “full field” of view. You want a rifle scope that offers generous eye relief so the recoil of your gun doesn’t give you a black eye (this can happen!) but also allows for a large site picture.
A housing that the eye piece and tube gets attached to.
A variable power rifle scope will have a ring you can rotate to change the magnification of the scope. When turning the ring you are changing the distance the internal lenses are from the objective lens, therefore changing the amount the light going through the scope is refracted.
Shifts the aiming point of the scope on the horizontal (left/right) plane. Used to “sight in” your scope. Often measured as a “Minute of Angle” each ‘click’ of the knob you turn changes the aim point a certain amount at 100 yards. For example, a ¼ MOA changes the aim point ¼” left or right at 100 yards. A 1/8 MOA changes the aim point 1/8” left or right at 100 yards.
Shifts the aiming point of a rifle scope on the vertical (up/down) plane. Used to sight in your scope. Same MOA as windage adjustment applies only changes your aim point higher or lower.