How to Choose a Rifle Scope

Why Should You Get a Rifle Scope?

These days, most firearm enthusiasts use some kind of optical sighting device on most of their guns. Not just rifles, but shotguns and handguns as well. There's a great reason for this: simplicity. Aiming through a scope or a red dot sight completely eliminates one-third of the complexity of lining up iron sights. With metallic sights, you are required to line up the rear sight with the front sight and your target. With a scope, you simply have to line up your crosshairs (reticle) with your target. It's much easier to learn to shoot with a scope than iron sights, and since most rifle scopes also magnify, your target appears closer which enables you to place a more precise shot

Novice shooters may be overwhelmed by the vast selection of scopes on the market. In this guide, we'll break down some important features and specifications to consider while you shop for the perfect riflescope.

How to Decide What Riflescope to Buy

You don't use a seven-ounce claw hammer to pound in sixteen penny nails or a baby sledge hammer for finishing nails. Magnumitis sinks its ugly claws into greater numbers of hunters every year. Cartridges and scopes get more powerful annually, and uninformed marksmen often use these combinations for whitetail deer where almost all shots are well under a hundred yards.

Overpowered calibers and high-magnification scopes account for more missed and wounded game than standard loads with appropriate scopes. "More" does not mean you can shoot any farther. Bullets go faster and optics magnify more because they sell better.

Manufacturers will make anything they think enough people want. Pink scopes? Start a petition. Square main tubes? Have enough people phone. This is fine. Some people might call this progress. But you need the right tool for the job.

A 3-9x scope, specifically a 3-9x40 scope, is considered one of the best scopes for deer hunting, and for good reason. Three power is low enough, with a large enough exit pupil and field of view for close shots in most applications, and nine power gives you plenty of magnification for longer shots. We have a wide selection of 3-9x scopes for sale if you want to take a look at available options.

A major percentage of people now want to choose scopes for whitetail deer with top magnifications of fourteen, or twenty, or even more. This is, more often than not, a mistake. Less is more. Use the kiss principle. Bells and whistles like giant turrets and bubble levels are often a waste, particularly in lower-priced models.

If you aren't experienced enough to know why you want these upgraded features, then you're just adding a more complicated and less-reliable optic to your firearm. You have enough to do without troubling over how to work your scope. Our best-rated riflescopes have quality attributes that can be relied on.

Not only does higher magnification subtract from your exit pupil size and available light, but the low end of a high magnification scope is much too high to take a very close shot. Your scope on a whitetail rifle should almost always be kept at its lowest power. If that power happens to be five or six, many times your deer appears as a hairy patch through your scope, your field of view is so narrow you can't find him, or it's so dark you can't make him out.

Just as those bold Navy pilots, it's prudent to know how low a scope goes, not how high. Low is more important in most cases. You can always shoot far with low power, or have time to turn the scope up, but you can't shoot close with high power because your field of view (FOV) and exit pupil are too small.

What Do the Numbers Mean on a Rifle Scope?

In a 3-9x40 scope, the 3 means three power, or 3x. This means that the image you see through the scope appears three times (3x) closer than it does with your naked eye. The 9 means nine power, or nine times (9x) closer than it appears with your naked eye. The forty (40) is the objective lens diameter in millimeters. This is a variable scope because you can adjust the magnification of the scope from three to nine, stopping anywhere in between. You would describe this scope as a "three to nine by forty." The larger the magnification range, the more you will pay, but it makes for a more versatile scope. In a lot of cases, a versatile scope means that you can use one optic for multiple applications instead of buying another one. You can read more about scope numbers here.

Light Transmission and Eye Relief Explained

Scopes don't gather light, as most people think, although the term "light gathering ability" has become accepted jargon. Scopes transmit available light through the lenses to your eye, always losing a bit in the process. The best a scope can hope to offer in light transmission is about a theoretical 98%, which only the very finest (read expensive) scopes can hope to approach. Anything above 95% is considered great, and most scopes are around 90%, give or take a bit. You have to take light transmission figures with a grain of salt. Manufacturers measure light transmission differently, sometimes for specific wavelengths to boost their numbers.

The more magnification you have, the less light you get to your eyepiece. The larger the objective lens, the more you get through your eyepiece.

Aged eyes may dilate to only about four millimeters. Younger eyes may open up to seven millimeters and even more. An exit pupil much larger than your eye can use is wasted. Like drinking out of a fire hose.

The small circle of light that appears in the eyepiece when you hold a scope at arm's length is called an exit pupil. Here's an interesting experiment to help explain it. Take a variable scope, put it at its lowest power, and hold it at arm's length. See the circle of light in the ocular lens? That is the exit pupil. The diameter of it in millimeters is the exit pupil size. Now turn the scope up to its highest power and try it again. See how much smaller it gets? Imagine if you are using this scope during poor lighting conditions as common in hunting situations, like dawn or dusk. How small and dark will that exit pupil be? How well do you think you'll be able to see through that tiny circle of light?

A formula for exit pupil is as follows: Divide the objective lens size in millimeters by the magnification. Example: if your 3-9x40 scope is set at 3x, 40 divided by 3 equals 13.3 millimeters, which is large enough for almost all low light applications. If your scope is set at 9x, 40 divided by 9 equals 4.44 millimeters. The difference in available light from the larger exit pupil is significant.

The larger the exit pupil, the less critical the position of your head in relation to the scope is, also. The distance that your eye must be to the ocular lens to get a full, clear picture is called eye relief. Lower powered scopes will have a larger range of distance available for a full view. Higher powered scopes are sometimes very critical in relation to the centering of your eye through the middle of the tube, and the distance your eye must be from the ocular lens. Sometimes there is only a half inch closer or farther you may be to see the whole available view.

The largest eye relief currently available for a standard riflescope is about four inches. Four inches is great, and offers enough room for the gun to recoil and not hit your face, if you do your job correctly. Most standard riflescopes have between three and three and a half inches. Higher recoiling guns including slug guns require lots of eye relief to prevent "scope eye" or the cut that some people get from the ocular lens of the scope coming back under recoil and cutting a semicircular gash above the shooter's eye. Shotgun, muzzleloader, and dangerous game scopes sometimes have 5 or 6 inches of eye relief to prevent scope eye, but often at the expense of field of view.

IER (Intermediate Eye Relief) scopes, also known as "Scout scopes" are mounted in front of the receiver of a long gun and require around 9-12 inches of eye relief. LER (Long Eye Relief) scopes, also known as "Pistol scopes" used on handguns may have around 16-20 inches of eye relief.

When mounting a scope, it should be at its highest power and in a position that your head and neck are comfortable. Your head should be placed on the stock in the position you will be shooting the most. For instance, if you sight in a gun while shooting off a bench rest, your head tends to sneak up on the stock a bit. If this gun is then used for snap shooting for deer in the woods, your eye relief and sight picture might not be optimal. Always mount your scope so you don't have to move your head for optimal field of view. Move the scope to your eye, not your eye to the scope.

What Is the Best Scope Magnification for Hunting?

As we have already discussed, a scope in the 3-9 magnification range for a whitetail deer gun is pretty standard. In Western states for mule deer or antelope, a 4-12 or 4.4-14 is not too much, especially when your average shot is many times as long as it would be in the eastern whitetail woods. On the plains or in open country you can even leave your scope at a higher power. You can often see all around you, with little chance of an animal surprising you, which they seem to do occasionally, anyway. In some cases you might have to shoot from hilltop to hilltop, or mountain to mountain. Hunting scopes in this magnification range are excellent for target shooting as well.

For prairie dogs or long-range target shooting, a 6-20x or 8-25x variable scope does not have too much power. Keep in mind though, on hot days, mirage and heatwaves can make a high power scope almost unusable.

Some people prefer fixed power scopes for their simplicity and fewer moving parts. On some rifles, people like nothing more than a fixed 4x. Squirrel rifles and many .22s for plinking are well equipped with this magnification. Some target shooters use fixed-power scopes with high magnification such as 24, 36, or 40 power.

A 2x scope is the most common for a handgun in a magnified scope. The more magnification you have, the harder it is to find your sight picture and target, and the more critical and closer your eye relief becomes. Shooting a handgun with a scope requires lots of practice, especially with anything over 2x. Higher powered variable scopes are really for the experienced shooter and are used almost exclusively from a rested position.

Shotgun scopes and muzzle loaders often have lower power scopes for short-range deer hunting with slugs, and for turkey. Again, a fixed 2x is fairly standard, but the trend is for variable power 2-7 or even 3-9 scopes. Sabot slugs for shotguns and muzzleloaders fly much faster and flatter than the Foster-type slugs and Maxi Balls they replaced not too long ago. These new projectile types make shots that were way out of range just two decades ago now very possible. Parallax is often factory set at 50, 60, or 75 yards. Shotgun and muzzleloader scopes generally have maximum available eye relief to prevent "scope eye."

Objective Lens Size and Tube Diameter Explained

Let's talk about objective lens sizes. 40 to 44mm is pretty standard on a medium variable rifle scope. It's trendy these days to have large objective lenses of 50, 56, or even 75mm and more in some cases. In most cases, these are unwarranted, and the largest ones are laughable.

Large objective lenses will only transmit more useable light than smaller ones if they are set at their highest power in the dimmest conditions. The detriment is comfort and ease of eye alignment. With a properly mounted scope, you should be able to close your eyes, shoulder your gun with a proper, repeatable stock weld (the stock weld is firm but comfortable and repeatable position of your face on the gun stock), open your eyes, and look directly through the center of your scope every time.

Large objective lenses prevent this from happening because of the ring height required to keep such a large lens off your gun barrel. Some scopes require such high mounting that only your chin touches the stock. These scopes are also heavier, clumsier, unwieldy, unbalanced to carry, slower and less comfortable to shoot. Some of these scopes weigh up to an unbelievable 3.5 pounds! Kind of like towing a motorcycle trailer or taping a bowling ball to your head.

Leupold has their excellent VX-L line of scopes that combine a large objective lens with a contoured bottom that doesn't interfere with your gun barrel, and lets you mount up to a 56mm lens with low rings!

The larger 30mm main tubes on some scopes are most useful for allowing for a greater range of elevation adjustments, not greater light transmission, although resolution can improve. In fact, most 30mm scopes have the same size lenses that are in 1in tubes. Again, a larger tube does not mean more light.

How to Choose Scope Mounts, Rings, and Bases

Most scopes, especially in America, have main tubes that are 1 inch in diameter. That means that they use 1in rings. Some scopes have 30mm main tubes. Those scopes will use 30mm rings. There are several main types of bases that are used to connect the rings to your firearm. You need to know what kind of base you have to find out the exact type of the 1in or 30mm rings you will use for your specific scope. The height of the rings is determined mainly by the objective lens diameter, but also the barrel thickness, action size and type, ocular bell diameter, and bolt lift. Here is my article on Choosing Mounts, Rings, and bases.

What Types of Lens Coatings Are There?

Most scopes are fogproof and waterproof. Most scopes have coated lenses. The coatings are expensive and vary in type, number, and quality. It is very possible to have a scope with single-coated lenses to greatly outperform a scope with multicoated lenses. It all depends on the quality of the glass and the coatings. Good quality does not come cheap.

The following are accepted terms for coatings:

• Coated: A single layer on at least one lens surface.
• Fully Coated: A single layer on all air to glass surfaces.
• Multicoated: Multiple layers on at least one lens surface.
• Fully Multicoated: Multiple layers on all air to glass surfaces.

Coatings reduce glare, and loss of light due to reflection. More coatings normally lead to better light transmission and sharper contrast. Many coatings are also scratch resistant.

Many optics have coatings that prevent water from staying on glass.

Hydrophilic coatings cause water to sheet from glass.

Hydrophobic coatings cause water to bead on glass.

Both work to shed water and allow clearer views in rain or misty conditions.

Field of View Explained

Field of view (FOV) is measured in feet at 100 yards. This is the amount of view you see through your scope from right to left at that distance. As magnification is increased, FOV goes down. As magnification is decreased, FOV goes up. For instance, a typical 3x variable scope might have a FOV at 100 yards of a bit over 30 feet, and at 9x, the FOV would be around 14 feet. A larger objective lens diameter will not change these figures. Field of view is directly related to the construction of the eyepiece.

What Are Tactical Rifle Scopes?

Another trend today is the sale of anything called "tactical." Military semi-automatic rifles in the hands of advertisement-gobbling civilians often have super-high magnifications up to, and even including, a ridiculous 40 power scope with an absurd 75mm objective lens weighing in at several pounds.

Real military snipers use top-quality fixed 10x scopes most often. These have mil-dot reticles that, in the hands of a practiced individual or team of two, often with calculators and knowing the approximate size of their target, can estimate distance and hold-over or elevation clicks. Almost all mil-dot calculations must be made with scopes at their highest power. Fixed power scopes eliminate miscalculations by having a scope set at less than its highest power.

The "mil" in mil-dot does not mean military. It means milliradian, a unit of measurement, and is about 3.6 inches at 100 yards.

Stateside law enforcement agencies most often use variable scopes of the highest quality, and mil-dot type reticles are not often used. They clutter the field of view, and the longest shots almost ever taken are across a street, well under 100 yards. Range estimation with a reticle is never required.

Mil-dot reticles in most people's scopes are nothing but a gimmick and an added expense. They will never use them the way they were designed, which is fine. You can still use them in the field to more accurately estimate hold-over at distances, especially for prairie dogs or plinking, or just because you want it. The reticles in a mil-dot do subtend (cover) more of your target than necessary, though. But buy what you like for any reason. You don't have to buy or not buy something because of someone else's opinion, or use it as designed.

The Best Scopes Are Repeatable

High-quality scopes are repeatable. That is, if you adjust your windage and elevation dials for point of impact at one setting, then move them around and shoot in different places, then back to the original place, the point of impact will be the same as it was when you started.

Good quality scopes will also move the point of impact when you adjust your dials, without having to "settle in." That is to say, if you move your elevation dial up three inches, your point of impact should immediately reflect that. Sadly, more often than not, lesser quality scopes won't do this without shooting a few times first, to "settle in" the scope's internal adjustments. Some people "tap" on their scope with a coin or cartridge case to help this process. "Shooting a box" is a good test of repeatability.

But repeatability is not that important in many scopes. Generally, you will sight in a rifle and leave it alone except for minor adjustments required due to changes in ammunition type. If you have a .22 and just want an inexpensive scope to top it off, you'll generally be fine without absolute repeatability, which increases the price of the product significantly.

Turret Adjustments and Minute of Angle (MOA) Explained

Adjustments are made in "Minutes of Angle" (MOA). This is a unit of measurement of a circle, and is 1.0472 at 100 yards. For all practical purposes, it is called 1 inch at 100 yards. It is 2 inches at 200 yards, 5 inches at 500 yards, one half inch at 50 yards, etc.

The turrets are housed in the center of your scope tube in a protrusion called the turret housing. The turrets are sometimes made to be turned with a coin, and sometimes they are finger adjustable. Target turrets are tall, and the clicks are easily seen and felt. Target turrets are most suited to use where they won't get banged around or snagged on gear or brush. This is why hunting scopes don't have them, and instead are much lower profile.

The turret caps are often sealed with an "O" ring, and help prevent moisture and debris from entering the scope through its weakest parts. Many scopes now have large dials, but with locking adjustments, to prevent their inadvertent movement. Most turrets also have a way to move or remove a turret or portion of a turret to correspond to zero after you sight it with a particular load.

What Are Bullet Drop Compensator (BDC) Reticles

At the turn of the century, BDC dials and reticles were often set for just a few cartridges, like 5.56 (223) 55 grain and 62 grain, or 7.62 (308) 168 grain, and were very suspect in terms of accuracy. Atmospheric conditions are varied, but the BDC dials stayed the same regardless of cartridge velocity, projectile BC (ballistic coefficient), temperature, barrel length, or elevation. They were ballpark, not precise, except for rare cases.

Enter the Nikon "Spot On Technology" website. This appeared in the mid-2000s, and was my favorite new product at the Vegas Shot Show that year. It is simply amazing. Just enter in any cartridge's ballistic information, whether factory or hand-loaded, and get the trajectory for that cartridge with any type of atmospheric information. It is used to find the distances that the Nikon BDC reticle circles line up with at any magnification. It will also work with any crosshair scope from any company. You can even print it out for reference or size it to be taped to your stock or scope for quick reference in the field.

Since "Spot On", many other companies have developed their own programs that have similar attributes. Some are very good, some are a bit heady and complicated. These programs are the most valuable development in riflescope use in decades and have the most to do with hunters' ability or desire to take longer shots than ever before possible. Whether you move a turret to adjust for distance, or use the stadia lines or circles in your reticle, these are here to stay, and a lot of the guessing game is completely gone. Used with skill and a laser rangefinder, these reticles and websites combine to make you feel quite empowered. They presume the shooter is capable of making ethical shots in the field, and the only way to ensure this is to burn powder with trigger time and good practice, not just shooting. For further information on reticles, take a look at our Advanced Reticle Guide.

How to Sight In Your New Scope

If your scope is correctly mounted, using a boresighter should get you close enough to print a bullet hole on a large target at 50 yards. No boresight, even a laser boresight, will sight in your gun for you. You must shoot the gun and adjust your scope accordingly to sight it in. Every gun is an individual. No two are alike, even if the serial numbers are consecutive. If a particular gun shoots a certain kind of ammunition well, there's absolutely no guarantee that an identical gun will like it at all.

If you mount a good scope on a good gun with good rings and bases, and find a certain kind of ammo that it shoots well, with a bullet that serves your purposes well, YOU WIN! Buy a case of the same exact ammo with the same lot number, keep it with the gun, and don't change a thing.

Also, your scope is at its strongest when your windage and elevation adjustments are in the center of the available adjustment range. This is called mechanical zero. When you buy a scope, turn the dials all the way one way and then the other, counting how many full and partial turns, then split that number and find the middle. Start there for your adjustments. Many rear bases have windage adjustments. Use them.

How Much Should You Spend on a Riflescope?

I would rather have a great scope than a great gun. Your gun will work when you pull the trigger, but if you can't see where to place the bullet, the gun is useless. If you can't rely on bullet placement, why even hunt or target shoot? I'll never understand how people can take a week or more vacation, spend $1000.00 on a rifle, and sometimes thousands on a hunt, and buy a $150.00 scope mounted on $20.00 rings and bases. I know of many ruined hunts, countless dollars lost, and guns wrapped around trees because of faulty scopes. I would rather spend $500.00 on a gun and $500.00 on a scope with good rings and bases, and lots of ammo and trigger time getting to intimately know my gun. During hunting situations, you often have enough to think about, including concealment, scent, and often at high elevations, just breathing. You shouldn't have to think about having to work your gun.

Put silk tapestry over a pressboard couch and you still have a piece of junk. A cheap two-ton jack may work once or twice before it folds into itself like a crushed beer can. Spend as much as you can afford on your new rifle scope, and less on the firearm or something else if you have to, but get good glass you can count on and learn how to use it well. Use a rangefinder if you want, but for long shots, you must know your bullet's trajectory and be confident that you can place all your shots in the vital area of your quarry every time. Good glass makes it easier for success.

Aim Hard,

Steven K. Ledin

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