How Does a Rifle Scope Work?

One thing has become clearer over the years and that is, target shooting has not just been limited to law enforcement agencies but, in fact, has been taken over seriously by many hobby shooters. Some consider it a pass-time, while others have adopted it as an extreme sport. Either way, rifle guns have taken over a whole new chapter and people are usually found browsing for better receptive and highly durable parts to complement their firearm.

There’s no doubt that using a scope makes it easier to hit targets at a longer distance with much greater accuracy because it helps to align the rifle with the target. A scope will improve your hunting or shooting accuracy significantly, and the quality of the scope you choose can actually matter even more than the quality of your rifle itself.

Before the Purchase

Before investing in a rifle scope for hunting, there are some considerations to consider. There is a common misconception regarding just how much magnification is necessary. When focus on shooting in the number, it’s nice to possess as much as you could find, but outdoors in the sector when a game animal can pop-up at any distance, lots of magnification is a handicap. Apart from the magnification, the size and design and excess weight of a rifle scope is one thing to consider before choosing one, as can be the purchase price.

After all, a shooter can much more likely hit a target using a great scope with a mediocre rifle, but even the best rifle won’t be of much use in hitting targets with a bad scope.

No matter if you are a hunter or just enjoy shooting for sport, you’ll know that choosing the best rifle scope is not an easy task and many variables have to be taken into consideration. The type of scope you’ll need depends heavily on the type of shooting you want to do. For example, a target shooter and a deer hunter will need different kinds of scopes.

If you are not experienced in this field, do not worry as well. On this page, I will try to give you an outline of the most important things you need to know when choosing a scope for your rifle.

Tips on Buying a Rifle Scope

By first reading up on their needs, the hunter or shooter can get a better idea of the scope they want, without paying for a lot of frills. When hunting deer and small game at short range, where fast shots are needed and under two hundred yard shots are standard, four power should be the max.

If I were doing a lot of short-range hunting, I would seek a compact scope with low power and finding a better lens coating to help with clarity. I think a fixed four power with 40 or 50 mild objective. I would like it to be set up to hit my shoulder perfectly in this way speed the time finding the target.

Most army scopes or tactical scopes are set up for speed for this very purpose.

Having the speed of finding your game in your scope fast is way smarter than trying to save time by carrying a loaded gun.

I have known hunters that use six power, but these are guys who know their scopes and practice finding objects in the scope fast. The way to do this is to follow with your scope something fast and small and keep it in the center of the scope’s field of view. I have done this and still use the idea to get used to a new scope. I try to follow a butterfly or small bird as it moves around in the trees. This exercise will help anyone a lot with the speed of shots and having your scope online as soon as the rifle is on your shoulder.

In buying a rifle, the scope you miss learning these things, but the basics are still the same.

You need to have scope the fits the gun and hits your shoulder in position. By this, I mean the field of view should be on target, and you should not have to move your head around to find the target. If you like the scope and gun. Consider you have to work to find the target in the scope, you will have a lot of work to change yourself in order successfully to hunt.

Objective Lens Size

The second number in the formula (4×40) is the diameter of the objective or front lens. The larger the objective lens, the more light that enters the scope, and the brighter the image.

You will certainly have to think about this before you buy a scope because if you shoot in low levels of light often. Or if you need to count times on your game, having a bigger front objective can mean a lot to you. For hunting elk where I need both more light and better magnification, I bought a new Leupold scope. It is a Four to twelve power rifle scope with a fifty mil front objective. One thing you can check when buying a scope is where it will fit on your gun. This can also be set using the rear aperture of the scope on most scopes.

Low power– (example: 1.5-6×32, 2-7×32) 

These riflescopes are ideal at close range, and for shooting moving targets. They provide the most effective light management and produce a brighter sight picture and a wider field of view-even in low-light conditions and thick brush.

Medium power– (example: 3-9×40, 2.5-10×50) 

Select these rifle scopes for hunting big game at medium range.

High power– (example: 6-18×40, 6-24×40) 

These riflescopes are best for target shooting when the target is motionless and for varmints and other small games.

For long-range shooting, the better options are the high power scopes with target range adjusters. I also like the Bullet drop compensator for this. I have seen and heard target range adjusters work perfectly, but I have not had the pleasure of owning one.

I also found using a spotting scope worked well in these hunting conditions.

In long-range scope choices, I found the longer scopes that are set close to the barrel of the rifle are a significant advantage. Longer scopes that sit lower to the rifle barrel are easier to site in. This will leave you with fewer variables to worry about.

Hunting and getting a big game at three hundred yards and more was the ultimate feeling. I had the feeling I was better at hunting.

Knowing the long-range capability of your gun makes sense because you can get more games. This happens because you are not restricted by your lack of knowledge. You get more games more often, and it makes hunting way more enjoyable.

Weapon scopes for precise shooting

Gun scopes are an excellent way to magnify an aim and hit it precisely. New technologies have made them lesser and additional precise. The latest trend in firearm scopes is making them magnify increased distances while becoming decreased in size.

A rifle scope, at the bare minimum, is a tube machined from a solid block of high-grade aircraft aluminum. The main outer tube can be a one or two-piece construction.

Main tubes are made from steel and titanium as well. Aluminum offers the best properties, while steel is heavy and corrosive.

How the Rifle Scopes Work 

The most integral parts of any rifle scope are the ocular lens, they work just like a telescope. From the objective lens, the light passes through and then the ocular lens magnifies that light using the focal point. When you look through a scope, the image you see is that light. 

Riflescopes also have a reticle, also known as a crosshair. These markers show the shooter exactly where the shot will go once he or she pulls the trigger.

The power ring is absolutely a great feature. It takes different magnifications to have different visions on your target starting from 3x to 9x. It means if you use the 3x vision, the target would be over three times closer to you than the ordinary vision, and it continues up to 9x vision. These scopes feature called a power ring. Turning the power ring changes the magnification setting on the scope.

Riflescopes also has a few controls that allow you to adjust the scope so that it’s in alignment with your rifle. 

The two controls that affect a scope’s sight are the windage adjustment and the elevation adjustment. 

– The windage adjustment tweaks the horizontal settings on a scope

– The elevation adjustment changes the vertical settings.

Most manufacturers set their rifle scopes so that they’re focused at 100 yards (91.4 meters). But switching magnification settings can introduce parallax error. With rifle scopes, parallax error is when the aim on a scope changes if the position of the shooter’s eye changes. Parallax error becomes a problem at high magnifications — most hunters won’t ever have to worry about it. Some manufacturers build rifle scopes with adjustable objective lenses that can correct for parallax error.

The main body of the rifle scope is the tube. There are two main diameter sizes of tubes for rifle scopes: 1-inch tubes and 30-millimeter tubes. It’s important to know the diameter of your scope’s tube so that you use the correct mounting rings when you attach the scope to your rifle.

Understanding Rifle Scope Specs

The Numbers

A riflescope’s numbers are arranged in a predictable pattern. They are like numbers that you will find on other optics, such as telescopes and binoculars. The first number will be the power of the magnification, the second number will be the size of the objective lens, listed in millimeters. The letter ‘x’ will divide both numbers.

Magnification

A riflescope’s magnification will let you know how powerful it is. More power is indicated by a larger number. A magnification of 2x means that the object being looked at will be doubled in size, 4x means it will be quadrupled, etc. Many scopes can be adjusted to different powers based on the need of the person using them. This type of variable power scope is indicated by two numbers before the x, indicating the lowest and highest possible powers. For example, a scope could be 3-9×40. This means it can be adjusted from 3x to 9x.

Objective Lens Diameter

This number indicates the size of the objective lens. Larger objective lenses provide more light for a person to see their target.

Light Transmission

Light transmission is the amount of usable light that passes through a riflescope or other type of optic device. It is a number that is represented by a percentage. This percentage is based on the total amount of original light that entered the scope. High-end scopes have a light transmission of 94 percent or better. This means that 94 percent of the original light is preserved and able to be used. Three other factors can determine light transmission: Effective use of the lenses in the scope, the use of anti-reflective lens coating, and the glass used in the lenses.

Eye Relief

Eye relief is the distance between your eye and the lens at the rear of the scope. The eye relief distance will provide a complete field of view with no dark ring around the edges. The desired amount of eye relief for most hunters is 3.5″ or more.

Parallax

This is the point inside the reticle’s position that the target appears at various ranges. It is most easily noticed when a person removes their eye from the dead center of the scope. Being “parallax free” means that the crosshair stays in the same position on the target, even if you move your eye off center in any direction. However, if the movement of your eye causes the target to move within the crosshair, “parallax error” is being experienced. This usually happens in variable magnification scopes that contain a large range in their magnification. As a way of preventing parallax error, some scopes have an adjustable objective. This enables a person to adjust the parallax to a specific range and magnification.

Objective Lens

The lens that is on the front of the riflescope is the objective lens. The amount of light that enters the riflescope is affected by the size of this lens. The bigger the objective lens, the more light will enter the scope. During cloudy weather, dusk and dawn, this is especially important. A larger amount of light gives the user better visibility, allowing targets to be seen during dark conditions.

Tube Diameter

In optics, the diameter of a lens is often a way to measure the magnifying power of the lens, equal to the number of times the linear dimensions of an object are increased. While the tube diameter plays a role in magnification, it does not affect the light transmission of a lens.

Lenses

A lens is a piece of curved glass found in an optic device, designed to increase the magnification of an object to make it appear closer than it is. The number of lenses used in a riflescope depends on the type and manufacturer of the scope you are using.

• Fog proof and waterproof

Many of the better riflescopes available on the market today will be fog proof and waterproof. A fog proof riflescope means that the air inside of the scope has been purged and replaced with argon or nitrogen. Then the scope is sealed to prevent any condensation or fogging on the lens from occurring. Waterproof, as the name suggests, means that the lens has been sealed to prevent water from getting in.

• Coated lenses

Glare and loss of light are reduced by the addition of microscopic coatings on the surface of a lens. These coated lenses help to minimize the amount of light that gets reflected and does not get transmitted through the lens. This provides an image that is higher in contrast, clearer and brighter. The more coatings that are put on a lens, the wider variety of wavelength light rays will be transmitted.

Field of View

Field of view (FOV) refers to the amount of area that can be seen through a riflescope from right to left at a distance of 100 yards. FOV decreases as magnification gets increased. For example, a 3x variable riflescope could contain a FOV of slightly over 30 feet at 100 yards. However, at 9x, it would now have a FOV of roughly 14 feet. These figures would not be changed by using a larger objective lens.

Turret Adjustments

The turret is one of the two knobs that are found on the outside center of the riflescope tube. These knobs have increments marked on them, usually in 1/4 MOA. In other words, a standard one-click change will impact ¼” at 100 yards.

The turret adjustments are used to compensate for windage and elevation, two factors that can affect the distance and direction that a bullet travels. Elevation refers to vertical adjustment, windage refers to horizontal.

Minute of Angle

Minute of Angle (MOA) is the unit of measurement used for a circle. It is 1.0472 inches at 100 yards. However, it is referred to as one inch at 100 yards, two inches at 200 yards, etc. The elevation and windage turrets on riflescopes correlate with MOA. Most scopes are made to adjust MOA at 1/4 MOA for each click.

Reticle

The reticle can be simply crosshairs, mil dots, or crosshairs with a set of smaller lines to compensate for bullet drop.

Bullet Drop Compensators

A system that can adjust a rifle scope to compensate for the drop of a bullet caused by gravity at different ranges, so the person does not need to hold under or hold-over while he or she is aiming

How the Lenses Work

– The objective lens is positioned full forward in the scope tube. 

– The target image is transmitted through the objective lens to an erector lens assembly.

– The target image is flipped to the proper orientation by the erector assembly and sent through to a magnifying lens, then onto the ocular lens.

– The ocular lens, the lens closest to the shooter’s eye, displays your target. 

Companies such as Nikon, Zeiss, and Leupold offer some of the best optic glass and coatings on the planet.

Pay close attention to the glass and its coatings when making a purchase decision. 

Let’s study in close detail what the objective lens 

An Objective Lens is housed in the objective bell, which is the large part of the tube body farthest from the shooter’s eye. 

Hunters need to be aware of the size of the Bell Housing and mounting on your rifle. If the bell housing is too large, you may need higher mounting rings or a different scope. 

Do not forget the quality of the Objective lens itself. Make sure it is excellent material and has a coating to improve target transmission. 

Superior quality glass material with excellent coatings reduces reflection and glare, a concern when picking out your target at sundown. 

Weight is another issue with a larger objective lens, stick with the 40 mm lens if extra weight is going to be a problem.

Some scopes have specially coated lenses. Coated lenses have a thin layer of synthetic material that reduces glare. That means the lens reflects less light, allowing more light to pass to your eye.

What are SFP and FFP? 

Before moving on to the ocular lens assembly, it is essential to have a brief explanation of first and second focal plane technologies in rifle scopes. 

First Focal Plane Scopes

First focal plane or FFP scopes have only been around for the last ten years and were introduced for long-distance shooting. 

In an FFP scope, the reticle is mounted in the first focal plane of the scope, which is back farther towards the ocular bell. With this design, the reticle starts tiny in the lowest power magnification setting and then grows larger as the power magnification increases.

Second Focal Plane Scopes

The SFP scope design has been around for years and years, and second focal scopes probably make up about 85% of all the rifle scopes that are currently on the market.

In a second focal plane scope, the reticle is mounted in the second focal plane area closer to the eye box of the scope. With this design, the reticle appears to be the same size regardless of the power magnification.

FFP strategies are gaining favor as optics, firearm materials, and ammunition have improved, allowing for long-range hunting. If all your shooting and hunting is done at the highest magnification, SFP scopes work fine. Before buying an FFP scope, look at the reticle at all power settings.

Types of Rifle Scopes

Some people confuse rifle scopes with gun sights. A good rule of thumb is that a rifle scope provides some level of magnification, whereas a gun sight doesn’t. Both devices help shooters aim at a target. Some sights are very simple, while others use lenses similar to a scope’s lenses. Here’s a brief rundown on common sight types:

• Open sights require shooters to line up two sights on a rifle to aim a shot. The rear sight usually looks like a V or a U. The front sight is a simple vertical projection.
• Aperture sights are like open sights, but use a ring for the rear sight. You align the front sight within the ring while aiming at your target.
• Red dot sights project a red dot or another illuminated targeting reticle on top of the image of the target. The dot doesn’t project out the end of the sight.
• Laser sights project laser beams toward a target.

The type of scope you need depends on the target you plan to shoot. If you plan to hunt big game at a distance of around 100 yards (91.4 meters) or less, you won’t need a high-power rifle scope. Anything more than 7x or 8x is unnecessary. 

If you’ll be shooting from a greater distance, you’ll need a more powerful scope. For example, if you’ll be more than 200 yards (182.9 meters) away from your target, you’ll need a scope in the 12x magnification range.

How do scope adjustments work?

Riflescope adjustments are made from various turrets and dials found on the top and sides of the primary tube.

– Elevation Adjustment (bullet impact, up or down) 

– Windage Adjustment (bullet impact, left or right) 

– Parallax (target focus) 

– Magnification

A rifle scope will allow you to adjust for windage and elevation so that you can account for wind direction and distance. Windage is the horizontal plane, while elevation is the vertical one – which is pretty logical if you think about it.

Some reticles are designed with markings to help shooters figure out where their shot will land at different distances, typically further than the zero. These types of reticles thus mean that there would be no need to adjust the scope’s zero.

How to Use a Rifle Scope

Scopes are used to increasing your accuracy when firing at long distances by magnifying the image of your target and providing you with a reticle that indicates exactly where your weapon is aimed. These scopes come in a variety of models and can provide anywhere from 1 to 50 times the magnification of your target. 

Remember that a stronger magnification does not make you a more accurate shooter, so it’s important to practice strong fundamentals while firing with a rifle scope.

Mounting and Understanding Your Scope

Most modern rifle scopes come either pre-drilled and tapped for a scope base or with grooved sections for mounting attachments. You must purchase mounting hardware that matches the design of your scope. 

If you purchased your rifle with a factory-installed scope, you will not need to purchase any hardware.

If your scope requires mounting rings, ensure you purchase ones with the correct inside diameter, as the body of the scope will be mounted inside the ring.

Align the reticle and adjust the eye with relief 

The reticle of your rifle scope is the image you see on the lens of the scope that indicates where the weapon is pointed. With the mounting rings lose, rotate the scope until the reticle is right-side up or until the cross is properly aligned (like a plus sign). With that done, adjust the distance the lens of the scope will be from your eye to ensure it won’t hit you when the weapon recoils.

As a general rule of thumb, mount the scope and an inch further forward than you feel is safe to be certain you won’t injure yourself or damage the scope when firing. You can adjust this distance more later.

Make sure you can easily see the reticle in your normal firing position.

Familiarize yourself with the different parts of the scope 

A rifle scope is usually composed of a body, eyepiece, objective lens, shoulder, and windage, elevation, and parallax knobs.

The eyepiece is the part of the scope you look through, and the objective lens creates the magnification of the target.

The shoulder of the scope is where the diameter increases to hold the objective lens.

Windage and elevation knobs can move the reticle side to side and up and down. 

Parallax knobs are rarely adjusted and affect the movement of the reticle with the target.

Determine if your scope has a single or variable power lens 

Most rifle scopes are single-powered, but if you’re unsure which your scope is, look for a power selector ring past the shoulder of the scope but before the objective lens. This adjustable ring will permit you to choose between different levels of magnification the scope can provide.

If you have a variable power lens in your scope, choose a setting to zero the rifle and keep it on that until the scope has been properly zeroed.

When hunting or in tactical situations, keep variable lens scopes set to the lowest magnification power to allow for the widest field of view while using the scope.

How to Mount, Balance, and Zero a Precision Rifle, by West Desert Shooter.

Assess the level of magnification your scope provides 

You can determine the strength of your scope by looking at its model number. A scope that is “4 x 30” means that an image will appear to be four times larger through the scope than it would appear to the naked eye. The 30 indicated the number of millimeters the scope’s objective lens is in diameter.

Remember that the higher the magnification, the darker your target will appear to be through the lens because of the amount of light that can pass through it. Larger diameter lenses allow more light to enter the scope, thus making the image brighter.

The higher the first number in your scope’s model number, the stronger the level of magnification it provides.

Scopes with variable power will have model numbers like “4-12 x 32,” which means you can adjust between four and twelve times magnification.

Aiming and Making Adjustments

Many scopes will come with an eye relief rating that will look like 3-9x. This means proper eye relief is between 3 and 9 inches from the eyepiece.

Be extremely careful. Keeping the scope too close to your eye may result in it hitting you due to recoil when firing.

If your scope does not provide an eye relief rating, determine it yourself by looking through the scope while it’s mounted on the rifle and adjusting it until you can achieve a good sight picture.

Establish a good sight picture

Depending on your shooting position, it may be difficult to maintain a good sight picture. Placing the weapon on a table or using a bipod can stabilize the weapon and allow you to achieve a proper sight picture.

Capturing a good-sight picture is more difficult with high magnification scopes than it is with lower ones.

Make adjustments based on the impact of your rounds 

While different manufacturers and models of scopes will have slight variations, the windage knob will always adjust the impact point of your rounds on the horizontal axis (left to right).

Elevation knobs adjust your aiming point on the vertical axis (up and down).

Refer to the manual for your scope to know how far each click of the windage and elevation knobs will alter your aiming point.

Adjust the parallax if need be 

Look at the target through your scope and ensure the reticle is completely visible and clear.

Move your head up, down, and to either side, as you adjust the parallax knob slightly.

Continue to adjust the knob until the reticle no longer seems to move with the target.

Use these tools to zero the rifle

Using a bipod or firing table can help you keep the weapon completely still as you fire rounds to establish a zero. 

Use the windage knob to move the impact point horizontally and the elevation to adjust it vertically.

Practice proper breath control by breathing in, then out, and firing the weapon in the natural pause between your exhale and the next inhalation.

Utilize good trigger control by squeezing the trigger in a slow steady motion, then holding it in the fire position for a second after firing around.

Aim at the same point with each round, then adjust the scope to bring the reticle and impact points together.

Conclusion

Riflescopes are some of the best-engineered, technologically advanced products on the planet. World brands such as Nikon, Leupold, and Zeiss have brought their considerable optic technological advancements to bear on the industry. Companies such as Vortex and Nightforce are taking scope technology to unimaginable levels. 

Understanding the operational science, the parts, and the technicalities of a rifle scope will go a long way in your usage of such scope. Learn how to surf through the hype and beauty of scope to get through to the best.

Choose the best scope for your needs based on some concepts described above. Remember, the quality of the optics and their coatings play the most important role in hitting your target. Quality optical glass can last a lifetime if cared for properly.