Choosing an optic for your rifle can be a daunting task. There are many factors to consider that it may be hard to even know where to start! Regardless, a high quality optic is needed in order to retain its adjustments through shooting, traveling, and storage. Here are some basic things to consider when choosing an optic for your rifle.
Power
The first question you need to ask yourself is, what type of power am I looking for? Shooting at a target that is 100 yards away versus 1,000 yards away will determine which power setting is best. Also, what type of targets am I aiming at? If I am participating in a shooting competition where I just need the ability to see my targets whatever the distance, or if I am hunting in cover and need fast target acquisition, a lower power variable would give me a larger field of view. However, if you need to tell the difference between targets at a longer distance for spotting and target identification, you might want to consider something higher. For hunting, you may also consider that you can place the crosshairs more accurately if you can see the target better. A scope like the Nightforce 2.5-10×42 will give you a clear sight regardless of high or low magnification. Clear optics are necessary in order to be accurate as well as effectively be able to read the wind surrounding the target.
Objective Lens
The size of the objective lens will determine how much light will be in the scope. The crosshairs inside a larger lens will be visible longer. A larger lens will perform better in low light conditions. But with a larger lens, you will also need higher rings and a higher cheek piece as the scope will sit higher above the barrel. You will, however, have more field of view with a larger lens. The size of the objective lens is found after the magnification of a scope. For example, a 3-9×40 scope has a magnification range of 3x to 9x and the objective lens has a diameter of 40mm.
Adjustable Objectives
Adjustable objectives are common for shooters who are at various ranges and long range targets. It will allow you to fine tune the focus of the crosshairs for your personal eyesight comfort.
Parallax
Parallax is the difference between your reticle and the focal plane of what you’re actually looking at. In long ranges, this can have a high impact on the accurate placement of your shot. The crosshairs need to stay at the same spot on your target regardless of the angle you are looking into the objective lens from. If not, you will need to adjust for parallax which is usually done using a side turret.
Reticle
Reticles are the lines, dots and hashmarks that are used to aim the rifle at the target. This is commonly to as the crosshairs. There are many types of reticles to choose from. Some common ones are duplex, crosshairs, and mildot.
Turrets
Rapid adjusting turrets are popular among long-range shooters as they make elevation and windage adjustments easier by hand instead of requiring a tool. If you choose these style turrets, make sure they are consistent and check them frequently, especially to ensure that it was not accidentally rotated from the rifle being removed from a case. Some audibly click when turned, while others do not.
Low Light Capabilities
With an illuminated reticle, you will be able to see the crosshairs in low light conditions. Some light up the center, the dot, or the entire reticle. Night vision scopes or night vision attachments for your scopes are also useful accessories. Certain devices will wash out if there is ambient light on or near the target, so if you are using a day and night scope, you may want the illuminated reticle. Vegetation, cloud cover, and inclement weather are also contributing factors of where an illuminated reticle can help improve sighting.