Description
Rifle Scope Product Details
U.S. Optics FDN-17X Riflescope
The U.S. Optics FDN-17X Riflescope, 3.2-17x50mm, 34mm Tube, FFP, HORUS H102 Reticle, 1/10 MIL Elevation/ Windage Adjustment, Black, Medium, FDN 17X H102 Objective Lens Diameter: 50, Magnification: 3.2 – 17, Reticle: Horus Vision H102, Tube Diameter: 34, Reticle Focal Plane: First Focal Plane (FFP), Exit Pupil: 3, Battery Type: CR2032, Field of View, Linear: 25.25 – 8.03, Color: Matte Black, Weight: 29.6, Fabric/Material: Aluminum, Length: 15.02, Width: 3.883, Height: 2.43, Illumination Type: LED, Illumination Color: Red, Adjustment Type: Mil Rad, Adjustment Click Value: 1/10, Parallax: 50, Finish: Type III Hard Coat Anodized, Magnification Type: Variable, Conditio
Rifle Scope Product Features
3.2-17x50mm, 34mm Tube
FFP, HORUS H102 Reticle
1/10 MIL Elevation/ Windage Adjustment
About the U.S. Optics Company
U.S. Optics is a premium supplier for long gun scopes, optics, mounting solutions, and other accessories used for firearms like rifles and long guns. They design and manufacture their mounts and related products working with building materials which are long lasting and resilient. This includes the U.S. Optics FDN-17X Riflescope by U.S. Optics. For more shooting items, visit their site.
Information About Glass
Rifle scopes permit you to specifically align a rifle at different targets by aligning your eye with the target at range. They do this through zoom using a series of lenses within the scope. The scope’s alignment can be adjusted for the consideration of different natural factors like wind speed and elevation decreases to make up for bullet drop.
The scope’s purpose is to help the shooter understand exactly where the bullet will land based upon the sight picture you are seeing using the optic as you align the scope’s crosshair or reticle with the target. The majority of modern rifle scopes have about eleven parts which are arranged internally and externally on the scope. These optic pieces consist of the rifle scope’s body, lenses, windage and elevation dials, focus rings, and other components. See all eleven parts of scopes.
Rifle Glass Varieties
Rifle scopes can be either “first focal plane” or “second focal plane” type of optics. Choosing the finest type of rifle glass is based around what type of shooting you plan to do.
Info About First Focal Plane Optics
First focal plane glass (FFP) include the reticle in front of the magnification lens. This causes the reticle to increase in size based upon the level of zoom being used. The benefit is that the reticle measurements are the same at the magnified distance as they are at the non amplified distance. For example, one tick on a mil-dot reticle at 100 yards without any “zoom” is still the same tick at 100 yards with 5x “zoom”. These kinds of scopes are useful for:
- Quick acquisition, long distance types of shooting
- Shooting circumstances where estimations are low
- Experienced shooters who have an idea for their aim point “hold over” plus “lead” correlations for their long guns
- Shooters who don’t mind the reticle is enlarged and takes up more visual eyesight area than a SFP reticle
Second Focal Plane Scopes
Second focal plane scopes (SFP) feature the reticle to the rear of the magnifying lens. This triggers the reticle to stay at the exact same size in connection with the amount of magnification being used. The result is that the reticle dimensions adapt based on the zoom applied to shoot over greater ranges given that the markings present various increments which vary with the magnification. In the FFP example with the SFP optic, the 5x “zoom” 100 yard tick would be 1/5th of the non “zoom” tick measurement. These types of scopes are handy for:
- Long distance kinds of shooting where shooters have extra time to make ballistic calculations
- Shooting where most of the shots occur within much shorter spaces and ranges
- Shooters who select a clearer optic sight picture with less area used up by the larger size FFP reticle
Ins and Outs of Scope Zoom
The measure of scope magnification you need on your scope depends upon the type of shooting you plan to do. Almost every kind of rifle glass provides some degree of zoom. The amount of magnification a scope provides is determined by the diameter, thickness, and curves of the lenses inside of the rifle scope. The zoom of the optic is the “power” of the opic. This means what the shooter is aiming at through the scope is amplified times the power aspect of what can generally be seen by human eyes.
Single Power Lens Rifle Glass
A single power rifle optic and scope uses a zoom number designator like 4×32. This means the zoom power of the scope is 4x power and the objective lens is 32mm. The zoom of this type of optic can not adjust because it is a fixed power optic.
Info About Variable Power Lens Scopes
Variable power rifle scopes can be adjusted between magnification levels. It will note the magnification degree in a configuration such as 2-10×32. These numbers mean the zoom of the scope could be changed between 2x and 10x power. This always incorporates the powers in-between 2 and 10. The power modification is accomplished by working with the power ring component of the scope near the back of the scope by the eye bell piece.
Power and Range Correlations
Here are some suggested scope power levels and the distances where they can be efficiently used. Consider that higher magnification scopes and optics will not be as efficient as lower powered scopes because excessive zoom can be a detractor. The exact same concept applies to extended ranges where the shooter needs adequate power to see precisely where to best aim the rifle at the target.
Details on Rifle Scope Lens Covering
All present day rifle optic and scope lenses are covered. Lens coating is an essential aspect of a rifle system when considering high end rifle optics and scope setups.
HD Versus ED Lens Coatings
Some scope suppliers even use “HD” or high-definition glass coatings which use different procedures, rare earth compounds, components, and polarizations to extract separate color ranges and viewable target definition through lenses. This high-definition finish is often used with higher density lens glass which reduces light’s chance to refract by means of the lens glass. Some scope brands use “HD” to describe “ED” signifying extra-low dispersion glass. ED deals with how certain colors are presented on the chromatic spectrum and the chromatic aberration or difference which is also called color distortion or fringing. Chromatic aberration may be visible over items with well defined outlines as light hits the object from specific angles.
Rifle Scope Lens Single Finish Versus Multi-Coating
Various optic lenses can also have various coatings applied to them. All lenses usually have at least some kind of treatment or covering applied to them prior to being used in a rifle scope or optic. Because the lens isn’t simply a raw piece of glass, they require performance enhancing coatings. It becomes part of the carefully tuned optic. It needs to have a finishing placed on it so that it will be optimally functional in numerous kinds of environments, degrees of light (full VS shade), and other shooting conditions.
Single coated lenses have a treatment applied to them which is generally a protective and boosting multi-purpose treatment. This lens treatment can preserve the lens from scratches while reducing glare and other less beneficial things experienced in the shooting environment while sighting in with the optic. The quality of a single layered lens depends upon the scope maker and how much money you spent paying for it. The scope’s maker and cost are indications of the lens quality.
Some scope makers also make it a point to specify if their optic lenses are covered or “multi” covered. Being “better” depends on the producer’s lens treatment innovation and the quality of materials used in developing the rifle scope.
Hydrophobic Scope Lens Finish
Water on a lens doesn’t assist with maintaining a clear sight picture through a scope at all. Numerous top of the line and military grade scope companies will coat their lenses with a hydrophilic or hydrophobic anti-water finishing.
Alternatives for Mounting Rifle Optics on Long Guns
Installing approaches for scopes can be found in a couple of options. There are the standard scope rings which are individually mounted to the optic and one-piece scope mounts which cradle the scope. These different types of mounts also typically come in quick release versions which use toss levers which allow rifle shooters to rapidly mount and remove the glass.
Hex Key Rifle Scope Rings
Basic, clamp design mounting scope rings use hex head screws to position to the flattop design Picatinny scope mounting rails on rifles. These kinds of scope mounts use a pair of individual rings to support the optic, and are made from 7075 T6 billet aluminum or similar materials which are developed for long distance accuracy shooting. This form of scope mount is excellent for rifles which need to have a durable, unfailing mount which will not move regardless of just how much the scope is moved or abuse the rifle takes. These are the type of mounts you want for a devoted optics setup on a far away hunting or interdiction long gun which will hardly ever need to be modified or adjusted. Blue 242 Loctite threadlocker can also be used on the mount screws to keep the hex screw threads from wiggling out after they are installed tightly in position. An example of these mounting rings are the 30mm type made by Vortex Optics. The set normally costs around $200 USD
Rifle Scope Mounting Solutions with Quick-Release Cantilever Rings
These types of quick-release rifle scope mounts can be used to quickly remove a scope from a rifle and reattach it to a different rifle. If they all use a similar style mount, multiple scopes can also be switched out. The quick detach mount style is CNC machined from anodized 6061 T6 aluminum and the mounting levers attach securely to a flat top design Picatinny rail. This lets the scope to be sighted in while on the rifle, removed from the rifle, and remounted while maintaining the original sighting settings. These types of mounts come in convenient for shooting platforms which are hauled around a lot, to take off the scope glass from the rifle for protection, or for aiming systems which are adopted in between multiple rifles. An example of this mount style is the 30mm mount from Vortex Optics. It normally costs around $250 USD
Info on Glass Tube Sealing and Gas Purging
Wetness inside your rifle optic can destroy a day of shooting and your highly-priced optic by triggering fogging and creating residue within the scope’s tube. A lot of scopes protect against wetness from entering the scope tube with a series of sealing O-rings which are waterproof. Generally, these water-resistant optics can be immersed within 20 or 30 feet of water before the water pressure can force moisture past the O-rings. This should be plenty of humidity avoidance for basic use rifles for hunting and sporting purposes, unless you intend on taking your rifle aboard a watercraft and are concerned about the scope still functioning if it is submerged in water and you can still retrieve the rifle.
Gas Purged Rifle Optic Tubes
Another part of preventing the accumulation of wetness inside of the rifle optic’s tube is filling the tube with a gas like nitrogen. Given that this area is currently taken up by the gas, the optic is less impacted by temp changes and pressure variations from the external environment which may potentially enable water vapor to seep in around the seals to fill the vacuum which would otherwise be there. These are good qualities of a good rifle scope to look for.
