How to Choose a Rifle Scope

Having the right rifle scope is an essential part of any hunt or target shoot. Whether you’re hunting a trophy buck or practicing your aim, our rifle scope buying guide will help you determine the most important features so you can choose the right scope for your pursuit. From magnification power to the adjustment systems available, you’ll learn everything you need to narrow down your scope choices.

Parts of a Scope

Rifle scopes have four major parts: the eyepiece, the tube, the adjustment knobs, and the objective lens.

The eyepiece is the lens closest to your eye and is what you’ll look through when aiming down your scope.

The tube All Sports Medicine tube diameter measures the thickness of the tube and determines which rings your scope is compatible with. The two most common tube diameters are 1 inch and 30mm: 1-inch scopes are lighter and thinner, while the larger 30mm scopes offer more adjustment opportunity and better lighter transmission.

The adjustment knobs are dials that allow you to make adjustments to the scope’s alignment and focus so your reticle (the aiming point) is as accurate as possible.

The objective lens is the lens at the opposite end of the scope from the eyepiece and affects the amount of light that passes through the lens.

Scope Magnification & Objective Lens Diameter

When browsing for rifle scopes, you’ll notice that they are described by a set of numbers, for example 10x42. These numbers indicate the level of magnification (10x) and the objective lens diameter (42mm) of the scope. Choosing the right magnification and objective lens diameter for your application is of critical importance, since this affects how zoomed in and bright the image is.

Scope Magnification

The first number on a scope indicates the magnification power. For example, a scope with a 10x magnification will make an object appear 10 times larger than it does with the naked eye. There are two types of scope magnifications: variable power and fixed power.

Variable power scopes have an internal mechanism to adjust the magnification power. These scopes are the most widely used and offer great versatility since they can be adjusted to give you the best view of your target. The magnification range of the scope is indicated by the first set of numbers: a 4-12x44 scope can be adjusted anywhere from 4x to 12x magnification.

Fixed power scopes have a fixed magnification power that cannot be adjusted. While they are less versatile, some hunters prefer fixed power scopes because they have fewer moving parts and require less adjustment in the field. Like variable power scopes, the magnification is indicated by the first number: a 12x44 scope provides a magnification of 12x.

If you plan on shooting targets up to 100 yards away or hunting small game, you’ll generally want a magnification between 1x and 4x. This means your scope should have the ability to magnify at 1x, 2x, 3x, or 4x—if it’s a variable power scope, you’ll want the lower magnification to be in this range.

For shooting up to 200 yards or hunting deer and other larger game, you’ll want a magnification between 5x and 8x.

Finally, if you plan to shoot at ranges All Undergarments & Sleepwear, you'll want a magnification Big Game Decoys.

Objective Lens Diameter

The second number on a scope is the objective lens diameter. The objective lens is the lens at the furthest end of the scope and gathers light to illuminate the image you see. The larger the objective lens, the more light the scope gathers, creating a brighter image. Generally, most hunters will want an objective lens of 32mm to 44mm, since this provides a good balance between brightness and image quality. 

If you plan to shoot at long-range or extreme long-range, it’s best to have a 50mm or greater objective lens so that you can use a higher magnification. Also, if you plan on hunting or shooting at dusk, dawn, or other low light conditions, the added light-gathering power of a larger objective lens can make your image brighter relative to the conditions.

Eye Relief & Exit Pupil

Exit pupil is the width of the aperture, or opening, in the scope’s optic system. The exit pupil size affects the amount of light that enters the scope and determines how bright the image will be. To find the right exit pupil for you, use our chart below based on the time of day you’ll most often use the scope:

Eye relief is the distance the scope should be from your eye for optimal viewing. For example, if a scope has an eye relief of four inches, the eyepiece lens should be four inches from your eye when aiming down the scope. Most rifle scopes have an eye relief between three and four inches and are great for hunting.

 If you’re shooting a higher-powered caliber or hunting deer with a shotgun, the added recoil can drive the scope into your face at shorter eye reliefs. Because of this, scopes with an eye relief of 4.5 inches or greater are better suited for these kinds of firearms. If you’re shooting a rifle with very heavy recoil, such as a large caliber, you may even want to choose an eye relief between five and six inches.

Field of View

The field of view is the diameter of an area visible through the scope at the expressed range. If the field of view is listed as 30 ft./100 yards, you can see 30 feet across the horizon 100 yards away. Some scopes have a range for their field of view measurement, for example 30–10 ft./100 yards. This expresses the field of view at the lowest magnification (the first number) and the highest magnification (the second number). As the field of view gets larger, you’ll see more of an area farther away, but your image will also appear less zoomed-in at that range.

Adjustment Systems

MOA vs. MRAD

The adjustment system is an important part of a rifle scope, since this allows you to adjust your aim and ensure the scope is accurate. There are two adjustment measurement systems used in scopes: Minute-of-Angle (MOA) and milliradian (also called MRAD or MIL). Both MOA and MRAD are angular measurements and there isn’t a substantial difference between the two—they are simply different ways of measuring the same thing, like centimeters and inches. It’s best to choose a scope with the measurement system you are most familiar with since this will make it easier for you to sight-in and adjust your scope.

That being said, if you’re getting into long-range shooting, you’ll likely want to choose an MRAD/MIL scope. MRAD systems make a larger adjustment for every click of the dial (the adjustment click value). The farther your bullet travels (as in long-range shooting), the more you’ll need to adjust your point of aim. Because MRAD systems have higher adjustment click values, you’ll ultimately need to click the adjustment dials less when sighting in your long-range scope. Also, since most long-range shooters use MRAD, it will be easier to communicate if you use the same adjustment system.

Parallax Adjustment

Most rifle scopes have two adjustment dials for changing the windage (horizontal axis) and elevation (vertical axis) of your reticle. Some scopes have a third dial used for adjusting parallax. Parallax is an inconsistency in the focal point of a scope that causes the reticle to move across the target as you change eye position. For an example of parallax, cover an object about 10 ft. away with your thumb, then alternate closing your left and right eye. Your thumb will appear to move even though it’s staying still—this effect is parallax.

Parallax adjustment combats this effect, preventing your reticle from moving around the target as you shift your eye position. Several modern scopes have a parallax adjustment regardless of their range, but you’ll especially want to make sure your scope has a parallax dial if you intend to shoot long-range or are using a scope with a magnification greater than 10x.

Lens Coatings

Just like the windows on your car, the glass used in scope lenses is treated with a variety of coatings to help reduce glare and fogging and protect the lenses from damage. There are four terms used to describe the coatings on scopes:

• Single-coated lenses have an anti-reflective coating applied to one surface of one lens.
• Fully-coated lenses have one layer of coating applied to both surfaces of all lenses.
• Multi-coated lenses have at least one lens with multiple layers of coatings and may have other lens surfaces with one layer of coating.
• Fully multi-coated lenses have multiple layers of lens coating on all surfaces of all lenses. These usually offer the clearest, most detailed image.

Scope Mounting Systems

You’ll also want to consider how the scope will mount to your firearm. There are three common styles of scope mounting systems: rings, bases, and rails.

Scope rings attach the rifle scope to your firearm. Rings consist of two pieces: a lower half that attaches to your rifle and an upper half that screws into the lower half to secure the scope. Scope rings are available in a variety of styles designed for different mounting systems, like directly to the barrel or via a base or rail.

Bases are a mount that allow you to attach certain styles of scope rings to a firearm. The most common scope bases are Cantilever mounts and Dovetail mounts.

Rails are a type of base that have several slots to allow quick attachment of your scope, sight, or other accessories. Popular rail types include Picatinny rails (also called MIL-STD-1913 rails) and Weaver rails.

Have more questions about the right scope for your next hunt or target shoot? Stop by your local ERLEBNISWELT-FLIEGENFISCHEN and talk to one of our firearms or optics experts. They’ll be able to give you personalized advice tailored to your needs. Plus, ERLEBNISWELT-FLIEGENFISCHEN also offers mounting and bore sighting services so you can be sure your scope is ready for the field. To learn more about how to get your scope ready for the season, check out our guide to sighting in a rifle scope.