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You are here: Home / Rifle Scopes / NcStar 4X20 Compact Air Scope/Blue Lens (SCA420B),multi
NcSTAR Rifle Scope 1 NcStar 4X20 Compact Air Scope/Blue Lens (SCA420B),multi

NcStar 4X20 Compact Air Scope/Blue Lens (SCA420B),multi

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SKU: 81f5dcaf41bd Category: Rifle Scopes Tag: rifle scope
  • Description
  • Additional information

Description

Rifle Scope Product Details

NcStar 4X20 Compact Air Scope/Blue Lens (SCA420B),multi
Product Description
LED (Light Emitting Diode) 100% Safe for the Eyes, 22.0X33.0mm Objective Lens, Standard On/Off Switch, Red Dot reticle
Amazon.com
Maximize the performance of your firearm with the NcStar Tactical 4×20 air scope. Equipped with multicoated lenses that provide a crisp sight and a lightweight body, the scope is always ready for action.
Specifications
Magnification: 4x
Tube diameter: 0.75 inches
Objective diameter: 20mm
Field of view: 26.2 feet @ 100 yards
Eye relief: 2.5 inches
Exit pupil: 5mm
Reticle: Plex
Click value: N/A
Lens coating: Blue
Mount included: Dovetail rings
Exterior finish: Matte black
Length: 7.88 inches
Weight: 3.35 ounces

Rifle Scope Product Features

About this item
Tactical 4×20 air scope compatible with air guns
Multicoated lens ensure crisp, bright image
26.2-foot field of view @ 100 yards
Plex reticle; 2.5 inches of eye relief
Dovetail rings mount; measures 7.88 inches

About the NcSTAR Manufacturer

NcSTAR is a premium producer for weapon scopes, optics, mounts, and other accessories used for guns like rifles and long guns. They style and build their mounts, scopes, and related products working with elements which are long lasting and resilient. This includes the NcStar 4X20 Compact Air Scope/Blue Lens (SCA420B),multi by NcSTAR. For more shooting goods, visit their site.

What You Need to Know About Glass

Rifle scopes allow you to precisely aim a rifle at different targets by aligning your eye with the target over a range. They do this through magnification by using a set of lenses within the scope. The scope’s alignment can be adjusted to take into account varied ecological aspects like wind speed and elevation to make up for bullet drop.

The scope’s function is to understand exactly where the bullet will hit based upon the sight picture you are seeing via the optic as you align the scope’s crosshair or reticle with the target. Many modern rifle scopes and optics have around 11 parts which are found inside and externally on the optic. These parts consist of the rifle scope’s body, lenses, adjustment turrets, objective focus rings, and other elements. See all eleven parts of an optic.

The Types of Rifle Scopes

Rifle scopes can be either “first focal plane” or “second focal plane” style of scopes. The sort of focal plane an optic has decides where the reticle or crosshair lies relative to the optic’s magnification. It literally suggests the reticle is behind or before the magnifying lens of the optic. Looking for the most suitable sort of rifle optic depends on what style of shooting you plan on undertaking.

First Focal Plane Optic Info

First focal plane optics (FFP) feature the reticle ahead of the magnification lens. This induces the reticle to increase in size based on the amount of zoom being used. The result is that the reticle measurements are the same at the magnified range as they are at the non amplified range. One tick on a mil-dot reticle at 100 yards without “zoom” is still the identical tick at one hundred yards by using 5x “zoom”. These kinds of scopes work for:

  • Quick acquisition, far away types of shooting
  • Shooting circumstances where computations are small
  • Experienced shooters who recognize their aim point “hold over” and also “lead” correlations for their weapon
  • Shooters who do not mind the reticle is bigger and uses up more visual eyesight space than a SFP reticle

Second Focal Plane Glass

Second focal plane optics (SFP) come with the reticle to the rear of the magnifying lens. This triggers the reticle to remain at the same overall size relative to the amount of zoom being used. The effect is that the reticle measurements change based upon the magnification used to shoot over greater ranges considering that the reticle markings represent different increments which can vary with the magnification. In the FFP illustration with the SFP optic, the 5x “zoom” 100 yard tick measurement would be 1/5th of the non “zoom” tick measurement. These particular styles of optics work for:

  • Far away types of shooting where shooters have extra time to make ballistic calculations
  • Shooting where most shots take place within shorter ranges and distances
  • Shooters who choose a clearer optic sight picture without area used up by the larger size FFP reticle

Zoom for Glass

The quantity of scope magnification you need is based on the style of shooting you like to do. Just about every kind of rifle glass provides some amount of zoom. The volume of magnification a scope provides is identified by the diameter, density, and curves of the lens glass inside of the rifle optic. The magnification level of the scope is the “power” of the glass. This suggests what the shooter is observing through the scope is amplified times the power element of what can generally be seen by human eyes.

Single Power Lens Rifle Glass

A single power rifle scope and optic will have a magnification number designator like 4×32. This indicates the magnification power of the scope is 4x power and the objective lens is 32mm. The zoom of this kind of scope can not fluctuate since it is fixed.

About Adjustable Power Lens Rifle Scopes

Variable power rifle scopes can be adjusted between magnification levels. It will note the magnification level in a format such as 2-10×32. These numbers imply the magnification of the scope could be set between 2x and 10x power. This also utilizes the power levels in-between 2 and 10. The power manipulation is accomplished by operating the power ring part of the scope near the back of the scope by the eye bell piece.

Power Levels and Range

Here are some recommended scope powers and the distances where they can be efficiently used. Remember that higher magnification glass will not be as practical as lower magnification level scope and optics because excessive zoom can be a bad thing. The very same idea relates to extended ranges where the shooter needs to have sufficient power to see precisely where to best aim the rifle.

About Lens Finishing

All contemporary rifle scope and optic lenses are covered in special coatings. There are various types and qualities of finishings. Lens coating can be an essential element of a rifle’s setup when considering high-end rifle optics and targeting units. The glass lenses are among the most crucial pieces of the optic given that they are what your eye sees through while sighting a rifle in on the point of impact. The finishing on the lenses shields the lens surface area as well as assists with anti glare from refracted sunrays and color profiles.

HD Versus ED Lens Coatings

Some scope companies even use “HD” or high-def glass finishes which make the most of various procedures, chemicals, polarizations, and aspects to enhance separate color ranges and viewable target visibility through lenses. This high-def finishing is frequently used with more costly high density lens glass which drops light’s opportunity to refract through the lens glass. Some scope vendors use “HD” to describe “ED” indicating extra-low dispersion glass. ED deals with how certain colors are presented on the chroma spectrum and the chromatic aberration or deviance which is similarly called color distortion or fringing. Chromatic aberration can be visible around things with hard shapes as light hits the object from various angles.

Single Coating Versus Multi-Coating for Rifle Glass

Different optic lenses can likewise have different finishings used to them. All lenses normally have at least some type of treatment or finishing used to them prior to being used in a rifle scope or optic.

This lens treatment can protect the lens from scratches while decreasing glare and other less advantageous things experienced in the shooting environment while sighting in with the scope. The quality of a single layered lens depends on the scope maker and how much you paid for it.

Some scope makers also make it a point to define if their optic lenses are layered or “multi” coated. Being “much better” depends on the manufacturer’s lens treatment innovation and the quality of products used in building the rifle scope.

Hydrophobic Lens Finishing

Water on an optical lens does not help with keeping a clear sight picture through a scope in any way. Lots of top of the line and premium optic manufacturers will coat their lenses with a hydrophilic or hydrophobic covering. The Steiner Optics Nano-Protection is a good example of this type of treatment. It provides protection for the surface area of the Steiner scope lens so the H2O molecules can not bind to it or create surface tension. The result is that the water beads slide off of the scope to preserve a clear, water free sight picture.

Choices for Mounting Glass on Firearms

Mounting solutions for scopes can be found in a couple of choices. There are the standard scope rings which are separately installed to the scope and one-piece scope mounts which cradle the scope. These various types of mounts also generally are made in quick release variations which use manual levers which permit rifle shooters to rapidly mount and dismount the scope.

Scope Mounts with Hex Key Rings

Normal, clamp design 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 different rings to support the optic, and are often made from 7075 T6 billet aluminum which are developed for long distance precision shooting. This type of scope mount is excellent for rifles which require a resilient, sound mounting solution which will not move no matter how much the scope is moved or abuse the rifle takes.

Rifle Glass Mounts with Quick-Release Cantilever Rings

These kinds of quick-release rifle scope mounts can be used to rapidly connect and remove a scope from a rifle. If they all use a similar style mount, multiple scopes can often be switched out. The quick detach mount style is CNC crafted from anodized 6061 T6 aluminum and the mounting levers connect nicely to a flat top type Picatinny rail. This permits the scope to be sighted in while on the rifle, taken off of the rifle, and remounted while retaining the original sighting settings. These kinds of mounts are useful and practical for shooting platforms which are moved a lot, to remove the glass from the rifle for protection, or for sight systems which are utilized in between a number of rifles. An example of this mount style is the 30mm mount designed by Vortex Optics. It usually costs around $250 USD

Info Around Optic Tube Sealing and Gas Purging

Wetness inside your rifle optic can mess up a day of shooting and your expensive optic by causing fogging and developing residue inside of the scope tube. A lot of scopes avoid wetness from entering the scope tube with a system of sealing O-rings which are water resistant.

Gas Purged Rifle Glass Tubes

Another component of preventing the accumulation of moisture within the rifle scope tube is filling the tube with a gas like nitrogen. Since this space is currently occupied by the gas, the glass is less influenced by condition changes and pressure differences from the outside environment which may possibly allow water vapor to leak 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.

Additional information

Category

Rifle Scopes

Brand

NcSTAR

ASIN

B000R4HSW2

Reviews

Over 534

Reviews Rating

3.4 out of 5 stars

Prime

Amazon Prime

Shipping

FREE Shipping on orders over $25 shipped by Amazon

Best Sellers

Last update on September 7, 2026 // Source: Amazon API

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