All guns in general use some type of sighting system. Whether it's iron sights, red dots, reflex sights, or rifle scopes, pretty much every gun that fires a projectile must be aimed before shooting. Let's talk about rifle scopes and optics used to aim guns. Here we will cover all of the information about rifle scopes including how rifle scopes work, the terminology behind the rifle scope parts and pieces, and the different types of gun optics and rifle scopes.
After that, we will discuss differences between airsoft gun scopes versus real gun scopes and optics. There is quite a difference when selecting a nice rifle scope (a.k.a "glass") or weapon optic system depending if you plan to mount it on an airsoft gun, real firearm, or find a scope you can use on both your airsoft guns and real guns and firearms. Hint: The quality and scope's ability to handle recoil come into play a lot here. We will also make a list of the best traits and qualities to look for when selecting a scope.
The Purpose of Rifle Scopes
Rifle scopes allow you to precisely aim a rifle at different targets by aligning your eye with the target over a distance. They do this through magnification by using a series of lenses inside the scope. The scope's alignment can be adjusted to account for different environmental factors like wind and elevation to account for bullet drop. The scope's purpose is to understand exactly where the bullet will land based on the sight picture you are seeing through the scope as you line up the scope's crosshair or reticle with the target.
The Parts of a Rifle Scope and Terminology
Understanding The Basic Scope Parts and Components
Most modern rifle scopes have about eleven parts which are found internally and externally on the scope. These parts include the rifle scope's body, lenses, adjustment turrets, focus rings, and other components.
The eyepiece of the rifle scope is the metal assembly that holds the ocular lens scope component. This rifle scope piece is attached to the eye-bell section of the rifle scope. When shouldering a rifle to look through the scope, this is the end of the scope body nearest your face.
The ocular lens piece of the rifle scope is the lens inside the scope which is closest to your eye while looking through the scope. It is located at the back of the scope tube. This lens aligns with your eye to determine the field of view based on the eye relief. If you are too far from this lens, you will only be able to see part of the field of view with a "dot" which moves around as you gaze through the scope. Move your eye close to the lens until the full field of view is visible to your eye.
Eye relief is a concept which is based on a shooter's use of the ocular lens. Specifically, eye relief is the distance from the shooter's eye to the ocular lens which allows them to see the full view through the scope. This factor comes into play when the shooter is trying to look through the rifle scope. The viewing angle also depends on the eye relief of the scope. Look for a scope with an eye relief of approximately 3" to 4" which allows you to maintain a good sight picture.
The eye bell of the rifle scope is the part of the scope which houses the eyepiece and ocular lens. It is the term used to describe the outer scope housing at the rear of the scope which also attaches the eyepiece area to the scope tube. This can also be described as the section of rifle scope tube between your face and the power ring adjustment (if the scope has adjustable power magnification).
The rifle scope's power ring is located next to the eye bell down the scope tube away from the user. This rifle scope feature is found on variable power scopes. The power ring determines the magnification level of the scope. Think of this as another term for the "scope zoom". Users can usually twist the ring clockwise to increase the magnification. Twisting the power ring adjusts the magnification lens found inside of the scope between the ocular and objective lenses.
Reticle or Crosshair
The reticle or crosshair inside the rifle scope allows the shooter to sight the rifle accurately. This is the "cross" inside of the scope which many people visually think about when it comes to rifle scopes. There are several types of commonly used crosshairs including fine, duplex, mil-dot, and circle type crosshairs. Reticles can also be illuminated to be red (or sometimes other colors like green) to help see the reticle better in lowlight conditions.
Windage Turret Adjustment
The windage turret adjustment on the rifle scope allows the shooter to make slight reticle or crosshair adjustments to account for wind. The shooter usually has to measure the wind speed and angle using a handheld anemometer or wind gauge. These wind values can be used in a ballistic calculator to measure the rifle's trajectory offset due to the wind. The windage turret can then be adjusted to correct the rifle's accuracy.
Scope Turret Adjustments
Most turrets on rifle scopes come in two standard adjustment measurements. MIL or MOA. MIL stands for "milliradian" (same as MRAD). The standard measurement for 1 MIL is 3.6" at 100 yards. An adjustment turret which features 1/10th MIL dials provides 0.36" adjustment per click at 100 yards. MOA stands for "minute of angle". The standard measurement for 1 MOA is 1" at 100 yards. An adjustment turret which features a 1/4th MOA dial provides 0.25" adjustment per click at 100 yards.
Elevation Turret Adjustment
The elevation turret adjustment on the rifle scope allows the shooter to take the shooting height into consideration. If significant elevation and distances are in play, the elevation turret must be adjusted in a similar manner to the scope's wind turret. On real rifle scopes, these turrets work off of the MOA principle. Using this principle, the elevation turret can then be adjusted to correct the rifle's accuracy and offset the elevation.
Parallax Turret Adjustment
The parallax turret adjustment on the rifle scope allows for sighting adjustments between where the target's image appears on the lenses of the rifle scope and where the target actually lies on the range (because they may be different). These adjustments are a must on real rifle scopes at long distance ranges which span hundreds of yards, but are not really a factor when it comes to airsoft guns. To check to see if parallax adjustments are needed, try moving your eyes around the rifle scope's viewable range while still aiming down the scope. If the target moves around the scope's reticle, adjust the parallax turret a little bit at a time until the target's movement is not noticeable.
The scope tube of a rifle scope is the main housing component which holds all of the other scope components. The lenses and the reticle live inside of the scope tube. The adjustment turrets attach to the scope tube at the same point where the reticle is located inside the tube. The eye bell and objective bell are the front and rear portions of the scope tube.
The objective lens part of the rifle scope is the lens farthest away from the shooter. It is the last lens encountered in the rifle scope which faces the target. This objective lens is located inside of the objective bell area of the scope tube.
The objective bell is the very front part of the rifle scope tube. This part of the tube houses the objective lens of the rifle scope. This area on a scope may be bulbous in shape to accommodate a larger objective lens or it may be the same size as the rest of the rifle scope tube. This depends on the purpose, magnification, field of view, and other characteristics of the rifle scope. The objective bell area is also where shooters can attach sun shades scope add-ons to avoid lens reflections and glare.
Rifle Scopes Focal planes
When we think about the lenses on a rifle scope, we also have to consider focal planes. Rifle scopes can be either "first focal plane" or "second focal plane" type of scopes. The type of focal plane an optic has determines where the reticle or crosshair is located in relation to the scopes magnification. It literally means the reticle is behind or in front of the magnifying lens of the scope. Choosing the best type of rifle scope depends on what type of shooting you plan on doing.
First Focal Plane Scopes
First focal plane scopes (FFP) feature the reticle in front of the magnification lens. This causes the reticle to increase in size based on the amount of magnification being used. The result is that the reticle measurements are the same at the magnified distance as they are at the non magnified distance. For example, one tick on a mil-dot reticle at 100 yards without "zoom" is still the same tick at 100 yards with 5x "zoom". These types of scopes are useful for:
- Quick acquisition, long distance types of shooting
- Shooting situations where calculations are minimal
- Experienced shooters who know their target "hold over" and "lead" ratios for their rifles
- Shooters who don't mind the reticle is enlarged and takes up more visual sight room than a SFP reticle
Second Focal Plane Scopes
Second focal plane scopes (SFP) feature the reticle behind the magnification lens. This causes the reticle to stay the same size in relation to the amount of magnification being used. The result is that the reticle measurements change based on the magnification used to shoot over longer distances since the markings represent different increments which vary with the magnification. In the FFP example with the SFP scope, the 5x "zoom" 100 yard tick would be 1/5th of the non "zoom" tick. These types of scopes are useful for:
- Long distance types of shooting where shooters have more time to make ballistic calculations
- Shooting where most shots take place within shorter distances and ranges
- Shooters who prefer a clearer optic picture without space taken up by the enlarged FFP reticle
Rifle Scopes: First Focal Plane VS Second Focal Plane
by Vortex Optics
The amount of scope magnification you require depends on the type of shooting you want to do. Almost every type of rifle scope provides some level of magnification. The amount of magnification a scope provides is determined by the diameter, thickness, and curvatures of the lenses inside of the rifle scope. The magnification of the scope is the "power" of the scope. This means what the shooter is looking at through the scope is magnified times the power factor of what can normally be seen by human eyes.
Fixed Single Power Lens Scopes
A single power rifle scope will have a magnification number designator like 4x32. This means the magnification power of the scope is 4x power while the objective lens is 32mm. The magnification of this type of scope cannot change since it is fixed.
Variable Power Lens Scopes
Variable power rifle scopes can be. It will list the magnification level in a format like 2-10x32. These numbers mean the magnification of the scope can be adjusted between 2x and 10x power. This also includes the powers in-between 2 and 10. The power adjustment is accomplished using the power ring part of the scope near the rear of the scope by the eye bell.
Scope Power and Ranges
Here are some recommended scope powers and the ranges where they can be effectively used. Keep in mind that high power scopes will not be as effective as lower powered scopes because too much magnification can be a bad thing. The same goes for longer ranges where the shooter needs enough power to see where to best aim the rifle.
Power Range Chart
|4x||0s yard to 100 yards||4x is enough scope power to see close to mid ranges effectively|
|7x||50 yards to 200 yards||7x is enough scope power to see mid ranges effectively|
|9x||100 yards to 250 yards||9x is enough scope power to see mid to long ranges effectively|
|10x||150 yards to 300 yards||10x is enough scope power to see far mid to long ranges effectively|
|12x||200 yards to 350 yards||12x is enough scope power to see long ranges effectively|
|+14x||250 yards to +400 yards||14x and higher is enough scope power to see far long ranges effectively|
Optic Lens Coating
All modern rifle scope lenses are coated. There are different types and qualities of coatings. Lens coating can be an important aspect of a rifle when considering high end rifle optics and scope systems. The lenses are one of the most important pieces of the optic since they are what your eye looks through while sighting a rifle in on the target. The coating on the lenses protects the lens surface as well as helps with anti glare from refracted sunlight and color visibility.
HD Versus ED Lens Coatings
Some scope manufacturers also use "HD" or high-definition lens coatings which use different processes, elements, chemicals, and polarizations to draw out different colors and viewable definition through the lens. This high-definition coating is often used with higher density glass which lowers light's ability to refract through the lens glass. Some scope manufacturers use "HD" to refer to "ED" meaning extra-low dispersion glass. ED deals with how colors are represented on the chroma spectrum and the chromatic aberration which is also called color distortion or fringing. Chromatic aberration can be noticeable around objects with hard outlines as light hits the object from certain angles.
Single Coating Versus Multi-Coating
Different optic lenses can also have different coatings applied to them. All lenses usually have at least some type of treatment or coating applied to them before they are used in a rifle scope or optic. This is because the lens isn't just a raw piece of glass. It is part of the finely tuned optic. It needs to have a coating applied to it so that it will be optimally usable in many types of environments, degrees of sunlight (full VS shaded), and other shooting conditions.
Single coated lenses have a treatment applied to them which is usually a protective and enhancing multi-purpose treatment. This lens treatment can protect the lens from scratches while reducing glare and other less advantageous things experienced in the shooting environment while sighting in with the scope. The quality of a single coated lens depends on the scope manufacturer and how much you paid for it. Both are indicators of the lens quality.
Some scope manufacturers also make it a point to specify if their optic lenses are coated or "multi" coated. This means the lens has had multiple treatments applied to them. If a lens receives multiple treatments, it can show that a manufacturer is taking multiple steps to combat different environmental factors like an anti-glare coating, a scratch resistant anti-abrasion coating, followed by a hydrophilic coating. This also doesn't necessarily mean the multi-coated lens is better than a single coated lens. Being "better" depends on the manufacturer's lens treatment technology and the quality of materials used in building the rifle scope.
|Single Coated Lens||One lens with a single multi-purpose treatment applied to it||Most commonly the last external objective lens is treated|
|Multi-Coated Lens||One lens with multiple treatments applied to the same lens||Most commonly the last objective lens is treated multiple times|
Anti-Water Lens Coatings
Water on a lens doesn't help with maintaining a clear sight picture through a scope at all. Many top of the line and high-end scope makers will coat their lenses with a hydrophilic or hydrophobic coating. The Steiner Optics Nano-Protection is a good example of this type of treatment. It treats the surface of the Steiner scope lens so the water molecules cannot bind to it or create surface tension. The result is that the water beads sheet off of the scope to maintain a clear, water free sight picture.
Scope Mounting Options
Mounting solutions for scopes come in a few options. There are the standard scope rings which are individually mounted to the scope and one-piece mounts which cradle the scope. These different types of mounts also usually come in quick release versions which use throw levers which allow rifle operators to quickly mount and dismount the optics.
Standard, clamp style mounting scope rings use hex head screws to mount to the flattop style Picatinny scope mount rails on rifles. These types of scope mounts use two separate rings to support the optic, and are made from 7075 T6 billet aluminum which are designed for long distance precision shooting. This type of scope mount is great for rifles which need a durable, rock solid mount which will not move no matter how much the scope is moved or abuse the rifle takes. These are the style of mounts you want for a dedicated optics setup on a long distance hunting or competition rifle which will rarely need to be changed or adjusted. Blue 242 Loctite threadlocker can also be used to prevent the hex screws from backing out after they are mounted securely in place. The rings pictured are 30mm from Vortex Optics. The set usually costs around $200 USD
These types of quick-release rifle scope mounts can be used to quickly attach and remove a scope from a rifle. Multiple scopes can also be swapped out if they all use a similar style mount. The quick detach design is CNC machined from anodized 6061 T6 aluminum and the mounting levers attach securely to a flat top style Picatinny rail. This allows the scope to be sighted in while on the rifle, removed from the rifle, and remounted while maintaining accuracy. These types of mounts come in handy for rifles which are transported a lot, to remove the optic from the rifle for protection, or for scopes which are used between multiple rifles. The mount pictured is a 30mm mount from Vortex Optics. It usually costs around $250 USD
Scope Tube Sealing and Gas Purging
Moisture inside your rifle scope can ruin a day of shooting and your expensive optic by causing fogging and creating residue inside of the scope tube. Most scopes prevent moisture from entering the scope tube with a system of sealing O-rings which are waterproof. Usually, these scopes can be submerged under 20 or 30 feet of water before the water pressure can force moisture past the O-rings. This should be more than enough moisture prevention for standard use rifles, unless you plan on taking your rifle boating and are worried about the scope still working if it goes overboard and you can still retrieve the firearm.
Gas Purged Rifle Scope Tubes
Another component of preventing the buildup of moisture inside of the rifle scope tube is filling the tube with a gas like nitrogen. Since this space is already occupied by the gas, the scope is less affected by temperature changes and pressure differences from the outside environment which could potentially allow water vapor to seep in around the seals to fill the void which would otherwise be there. These are good qualities of a decent rifle scope to seek out.
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