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How To Select A Rifle Scope

Rifle Scope Hero

A scope makes using your firearm significantly easier. Instead of lining up iron sights and using the power of your regular eyesight to take aim at your target, a scope allows the user just to line up their crosshairs with the target, and many also provide magnification. Even if you can see your target relatively well, the magnification offered by a scope allows you to place your shot more precisely, leading to a good, clean kill in hunting rather than wounding the animal or missing it entirely.

Because of this, many gun owners opt to invest in a scope for their rifles, and increasingly even for shotguns and handguns. There are several important considerations when selecting the rifle scope that’s right for you, and there are so many rifle scopes on the market that choosing one can feel overwhelming. Don’t worry – getting clear on your needs and priorities is half the battle here. This article will guide you through the major choices and the elements to understand when selecting your rifle scope.

Determine Your Needs

Before getting into the details of rifle scope components, make sure you are clear on how you intend to use your rifle scope. There are many bells and whistles that can be attached to a rifle scope, but be sure to prioritize those elements you actually need, especially if you are on a budget.

First and foremost, consider what purpose you are using your gun for. If you keep a firearm for self-defense, a scope will likely not be very helpful. Self-defense emergencies generally happen at close quarters, where a scope will only get in your way.

If you use your firearm for target shooting, make sure the targets will be far enough away from you (over 100 yards) to justify a scope. If you are shooting targets at short distances, your regular eyesight (perhaps enhanced with glasses) will probably do just fine.

The most common use of rifle scopes is for hunting. If you are hunting, consider the distances you are shooting, the size of the game, and the terrain where you will be shooting. If you are in a densely forested area, a high magnification will do you little good, as trees will end up blocking most of your view anyway. But if you are planning to hunt in open plains, a high magnification will help you scan long distances for game.

Scopes By The Numbers

When you purchase a scope, it will be defined by a set of numbers. For example, it may be listed as a 4-16x50 scope. The numbers before the x refer to the magnification: a 4x50 scope will magnify the image 4 times, and a 16x50 scope will magnify the image 16 times. In this example, the 4-16x50 scope refers to a range: the scope can magnify the image between 4 and 16 times. The number following the x refers to the diameter of the objective lens in millimeters.



Get the magnification that you will actually need based on the type of hunting you are doing. In other words: more is not always better! If you are hunting game at short to medium distances but invested in a high magnification scope, you will not be able to see a creature that has crept up just a few yards in front of you. It will appear as a blip in the ultra-magnified scope.

Higher magnification does also mean less light gets into the objective lens. The more glass the light has to go through, the less light reaches your eye. Now, if you are hunting game at long distances, this is an easy trade-off. But if you don’t need it, opt for a lower magnification and enjoy a little extra illumination in your scope.

When selecting a magnification in the field, do some experimenting to determine what magnification you prefer at what differences. There are many opinions about which magnifications are best, and ultimately, it is for you to decide what works for you.

That said, a common approach is to use an increase of 3x magnification for every 100 yards of distance (a 3:1 magnification ratio). In other words, if aiming for a target 100 yards away, use a 3x scope; at 200 yards away, a 6x scope; and so on. This is certainly not to say that you can’t shoot targets with weaker magnification at these distances, but may help you find a place to start.

Fixed Magnification vs. Magnification Range

As mentioned above, many scopes come with a range of magnifications. If you will be using your rifle in a variety of situations and distances, these provide extraordinary versatility. You’ll be able to see shorter and longer distances with the same scope, allowing you to respond to the game around you.

The 3-9x scope has long been seen as a standard, handling close-up as well as far-off shots using the 3:1 magnification ratio. The 4-12x is popular for similar reasons. Long range target shooting, or hunting of small far-off game such as prairie dogs, will likely require magnifications up to 25x.

If you know you’ll be shooting at short to medium distances and don’t want to deal with the complexity of a magnification range, many people opt for fixed magnification, such as a 4x for squirrel rifles, or a 2x for a handgun. Finding your target is often easier with less magnification, so if you are reacting to fast-moving nearby critters, a lower, fixed magnification might be just right. Fixed scopes are also less expensive than those with a range.

Objective Lens Sizes

Make sure to determine what size scopes your firearm can attach to before getting your heart set on a larger diameter. You will need to purchase rings to mount the scope to your rifle, and larger rings are more expensive than smaller rings.

Mounted Scope

There is a huge range in available scope sizes. Most common are one-inch (25 mm) to 44 mm, and these sizes generally work for most types of hunting. In theory, the larger the diameter, the more light is let in. However, in practice, the difference is only appreciable at the scope’s highest power in the dimmest conditions. If you are not intending to shoot in particularly dim conditions, the bulky diameter of a 50 or even 75 mm objective lens is probably not worth the bulk, weight, and discomfort.

When considering a size for the objective lens, make sure you are able to mount the rifle easily. You should be able to shoulder your gun with proper positioning and look through the scope every time. If your objective lens is so large that you have to crane or otherwise contort yourself to look through the eyepiece, you will probably need something smaller.

Light Transmission

As mentioned above, higher magnifications mean less light is transmitted, and a larger objective lens will transmit more light.

Most scopes transmit light at around 90%, and anything over 95% is considered excellent. Be aware that manufacturers measure light transmission differently, so this number should likely not be your make-or-break decision on which scope to buy.

Lenses & Coating

Higher quality glass is, of course, going to be more expensive. Extra-low dispersion glass will yield a sharper image with more contrast and better replication of the colors of the field.

Lenses can come with many coatings to serve a variety of purposes, but the success of these coatings will ultimately depend on their quality and the quality of the glass.

At the least, your scope should be fog-proof and waterproof. Make sure your lens is coated to avoid buildup of condensation within the scope, especially if you frequently hunt in humid climates. If you travel to a variety of climates or live somewhere with extreme seasons, you may need to spend the extra money for more serious weather-proofing for your scope.

Marketing language can make it difficult to determine what level of coating you’re actually paying for. Following is a guide to the coating of your lens, from weakest to strongest:

  • Coated: One lens surface has one coating layer.
  • Fully Coated: All air-to-glass surfaces have one coating layer
  • Multicoated: At least one surface has multiple coating layers.
  • Fully Multicoated: All air-to-glass surfaces have multiple coating layers.

More coatings generally lead to better transmission of light, as they reduce glare and reflection. Coatings may also prevent water from staying on the glass: hydrophilic coatings cause water to sheet from the glass, while hydrophobic coatings cause water to form into droplets on the glass.


The distance your eye has to be from the scope in order to see the full image clearly is called the eye-relief. It is extremely important that the eye-relief of your scope be large enough for the recoil of your gun. Otherwise, when you fire the gun, the scope will hit you in the eye!

Distance from eye to scope

The standard eye-relief on most rifle scopes is 3-3.5 inches. If you have a high recoil gun, opt for a higher eye-relief. If you need more than 4 inches, you may need to get specialty scopes made for shotguns and hunting dangerous game. Intermediate Eye Relief scopes have 9-12 inches of eye-relief, and Long Eye Relief scopes may have 16-20 inches.

When you mount your scope, make sure you are mounting it at the correct eye relief for the position you will shoot from most frequently.

Parallax Correction

Parallax is a perceived difference in a target’s position based on the point from which it is viewed. Most scopes under 10x are already parallax corrected (meaning the lens is focused at a set distance already), and therefore not something the user has to worry about.

You can tell if your scope’s parallax is off using a simple trick. If your scope is corrected for a distance of 100 yards, try pointing the scope at a distinct target 30 yards away. Then, move your head off center. If just moving your head while keeping the rifle still causes the crosshairs to move off of your target, then the parallax needs to be adjusted.

Scopes of more than 10x generally have external parallax adjustments, or side focuses. These help you dial in the distance you’ll be shooting. Under 10x, they are generally not necessary, and will generally distract you from the more important settings on your rifle and scope.


As you shoot with your scope mounted, it may need adjusting over time. You may also want to adjust based on the windage or elevation you’re shooting at. These adjustments can be made with the rifle scope turret.

These adjustments are often measured in “Minutes of Angle” (MOA), which is a unit of measurement of a circle. Roughly, MOA is called 1 inch at 100 yards, and they are generally made in quarter-inch increments. Each time you “click” the turret, your point of impact moves by a quarter of an inch at 100 yards; by half an inch at 200 yards; and so on.

The MOA turrets are the most common and easy to use. Some turrets have clicks that are half-inch or even full-inch. Others don’t have clicks, and work as continuous dials instead. Some turrets can be adjusted with your fingers, while others are made to be adjusted by a coin.

Make sure that your turrets work consistently, and that they are able to return to zero after your shots. As you are shooting, check often that a turret wasn’t accidentally rotated, especially if your rifle has been moving around since your last shot.

Minutes of Angle vs. Mil Dots

Be aware of how your reticles relate to your turret adjustments. You want them to match, so that you can make adjustments based on what you are seeing in the reticles.

As mentioned, the most common turret adjustments are measured in Minutes of Angle (MOA). However, reticles and turrets also come in Mil Dot, which is a crosshair with dots leading to the center. The space between the dots is one milliradian, which gets shortened to mil.

Generally, either MOA or Mil Dot will work fine, and it’s alright to stick with what you are familiar with and comfortable using. If you are hunting at long distances, you may want a finer crosshair such as the mil-dot. This is a dotted reticle that helps you estimate your distance from the target, as long as you know the target’s size.

MOA adjustments are slightly more precise than mil dot adjustments, but mil values are a bit easier to communicate. If you are more used to centimeters and meters, mils will be easier to calculate; if you are more comfortable with inches and yards, go with MOA. If either seem good to you, find out what your hunting buddy uses. It’s easier if the two of you are on the same page.

Field of View

Field of View is the distance you can see left to right through your scope. The higher your magnification, the shorter your field of view.

If your scope says its field of view is 75 meters, that means you will be able to see 75 meters left to right through the scope itself.

You will need a higher field of view if you are in an area with a lot of brush, or if you will be running while following your target. For long distances, the higher magnification will be more important than the field of view, as you can take your time locating your target.

Rifle Scopes by Caliber

The specific workings of your rifle will determine what kind of scope you will need. If you are working with a firearm that has a hefty recoil, you will need more eye relief from your scope. If your rifle can’t shoot long distances, you probably won’t need to invest in a high magnification scope.

We’ve therefore put together a series of articles detailing the best scopes for different types of calibers and refiles.

In Conclusion

A quality scope is the best way to get an accurate shot at long distances, and is therefore as worthy of investment as your gun itself. Your scope should be repeatable: that is, holding your gun and your posture in the same position should result in the same image in your scope, over and over.

As with your gun, it will take some practice to get used to using your scope. Make sure it has the features that you need, and spend what you can to get high-quality materials. As a rule of thumb, plan to spend half as much on the scope and mount as you do on the rifle. If you haven’t purchased your rifle yet, include the scope and mount in your overall budget to determine what you can really afford. After all, what’s the point of a high-quality rifle if you can’t see your targets?