Last update on August 18, 2022 // Source: Amazon API
Rifle Scope Product Details
U.S. Optics FDN 17X H59
US Optics, FDN Series Rifle Scope, 3.2-17X50mm, 34mm Main Tube, First Focal Plane, 1/10 MIL Adjustments, Matte Black Finish, Digital Red Horus H59 Reticle
Rifle Scope Product Features
US Optics, FDN Series Rifle Scope
3.2-17X50mm, 34mm Main Tube
First Focal Plane, 1/10 MIL Adjustments
About the U.S. Optics Scope Maker
U.S. Optics is a premium maker for firearm scopes, optics, mounting solutions, and other add-ons used for firearms like rifles and long guns. They style and manufacture their scopes and related products by choosing materials which are resilient and long lasting. This includes the U.S. Optics FDN 17X H59 by U.S. Optics. For additional shooting items, visit their website.
Rifle scopes permit you to specifically align a rifle at different targets by lining up your eye with the target over a range. They accomplish this through magnification by employing a series of lenses within the scope. The scope’s positioning can be adapted for the consideration of separate natural elements like wind speed and elevation to make up for bullet drop.
The scope’s purpose is to help the shooter understand precisely where the bullet will hit based on the sight picture you are seeing with the scope as you line up the scope’s crosshair or reticle with the intended target. Many contemporary rifle scopes have around eleven parts which are located inside and on the exterior of the scope body. These optic pieces include the rifle scope’s body, lenses, modification turrets or dials, objective focus rings, and other elements. See all eleven parts of scopes.
About Rifle Scope Types
Rifle scopes can be either “first focal plane” or “second focal plane” type of scopes. Deciding upon the best type of rifle optic depends on what type of shooting you plan to do.
First Focal Plane Scope Facts
Focal plane scopes (FFP) feature the reticle in front of the magnification lens. These styles of scopes are helpful for:
- Quick acquisition, far away types of shooting
- Shooting scenarios where estimations are small
- Experienced shooters who understand their target “hold over” plus “lead” ratios for their firearms
- Shooters who do not mind the reticle is enlarged and takes up more visual sight room than a SFP reticle
Second Focal Plane Optics
Second focal plane glass (SFP) include the reticle to the rear of the magnifying lens. This causes the reticle to stay at the same scale in connection with the quantity of magnification being used. The effect is that the reticle measurements adapt based on the magnification employed to shoot over greater ranges considering that the markings represent various increments which can vary with the zoom level. In the FFP example with the SFP optic, the 5x “zoom” one hundred yard tick would be 1/5th of the non “zoom” tick measurement. These sorts of optics work for:
- Long distance kinds of shooting where shooters have increased time to make ballistic estimations
- Shooting where most shots take place within much shorter proximities and ranges
- Shooters who would like a clearer optic sight picture without area taken up by the larger sized FFP reticle
The amount of magnification a scope provides is figured out by the diameter, density, and curvatures of the lenses inside of the rifle scope. The zoom of the scope is the “power” of the scope.
About Single Power Lens Rifle Glass
A single power rifle scope comes with 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 optic can not fluctuate because it is a fixed power scope.
Adjustable Power Lens Glass Details
Variable power rifle scopes use enhanced power. The power change is handled by using the power ring part of the scope near the rear of the scope by the eye bell.
Rifle Glass Power Level and Range Correlation
Here are some recommended scope power settings and the distances where they can be effectively used. Highly magnified rifle scope glass will not be as useful as lower magnification glass given that too much zoom can be a negative aspect depending on your shooting distance. The same idea goes for extended distances where the shooter needs adequate power to see where to best aim the rifle at the target.
Details on Glass Lens Covering
All present day rifle scope lenses are layered. Lens coating can be an important element of a shooting system when looking at high end rifle optics and scope setups.
About Lens Coatings – HD Versus ED
Some optic makers also use “HD” or high-def glass coatings that employ various procedures, aspects, chemical substances, and polarizations to draw out a wide range of color ranges and viewable target visibility through lenses. This high-def finishing is typically used with higher density lens glass which decreases light’s chance to refract by means of the lens glass. Some scope makers use “HD” to describe “ED” signifying extra-low dispersion glass. ED deals with how certain colors are represented on the chroma spectrum and the chromatic difference or aberration which is also called color distortion or fringing. Chromatic aberration is often noticeable over objects with hard shapes as light hits the object from particular angles.
Single Finish Versus Multi-Coating
Various scope lenses can even have different finishings applied to them. All lenses typically have at least some kind of treatment or finish applied to them prior to being used in a rifle scope or optic assembly. Because the lens isn’t just a raw piece of glass, they require performance enhancing coatings. It is part of the carefully tuned optic. It needs to have a covering put on it so that it will be efficiently usable in numerous types of environments, degrees of light (full VS shade), and other shooting conditions.
Single covered lenses have a treatment applied to them which is typically a protective and boosting multi-purpose treatment. This lens treatment can safeguard the lens from scratches while lowering glare and other less useful things experienced in the shooting environment while sighting in with the scope. The quality of a single covered lens depends upon the scope designer and how much money you paid for it. Both the manufacturer and amount are indicators of the lens quality.
Some scope producers similarly make it a point to specify if their optic lenses are covered or “multi” covered. Being “better” depends on the producer’s lens treatment technology and the quality of materials used in building the rifle scope.
Anti-water Coating for Rifle Optics
Water on a scope lens does not help with preserving a clear sight picture through an optic at all. Lots of top of the line or high-end optic manufacturers will coat their lenses with a hydrophilic or hydrophobic finishing. The Steiner Optics Nano-Protection is a fine example of this kind of treatment. It deals with the exterior of the Steiner scope lens so the H2O particles can not bind to it or create surface tension. The outcome is that the water beads sheet off of the scope to preserve a clear, water free sight picture.
Options for Mounting Rifle Optics on Long Guns
Mounting approaches for scopes are available in a couple of options. There are the basic scope rings which are separately mounted to the optic and one-piece scope mounts which cradle the scope. These different types of mounts also usually come in quick release versions which use toss levers which enable rifle operators to rapidly install and dismount the glass.
Rifle Glass Mounts with Hex Key Rings
Normal, clamp style mounting scope rings use hex head screws to mount to the flattop style Picatinny scope installation rails on rifles. These types of scope mounts use a couple of separate rings to support the optic, and are often made from 7075 T6 billet aluminum which is designed for long distance accuracy shooting. This type of scope install is great for rifles which require a durable, rock solid mount which will not move no matter how much the scope is moved or abused.
Quick-Release Cantilever Rifle Optic Ring Mounting Solutions
These types of quick-release rifle scope mounts can be used to quickly connect and detach a scope from a rifle. Several scopes can also be switched out if they all use a similar designed mount. The quick detach mount style is CNC machined from anodized 6061 T6 aluminum and the mounting levers attach nicely to a flat top type Picatinny rail. This lets the scope to be sighted in while on the rifle, removed from the rifle, and remounted back on the rifle while retaining accuracy. These kinds of mounts come in practical for rifles which are carried a lot, to remove the scope from the rifle for protection, or for aiming systems which are chosen for use in between a number of rifles. An example of this mount type is the 30mm mount from Vortex Optics. It generally costs around $250 USD
What to Know About Glass Tube Sealing and Gas Purging
Wetness inside your rifle scope can mess up a day of shooting and your expensive optic by causing fogging and creating residue inside of the scope tube. Many scopes prevent moisture from getting in the scope tube with a system of sealing O-rings which are waterproof.
Rifle Scope Gas Purging
Another component of preventing the accumulation of wetness inside of the rifle scope tube is filling the tube with a gas like nitrogen. Considering that this area is currently occupied by the gas, the scope is less influenced by temp alterations and pressure differences from the outside environment which could potentially enable water vapor to permeate in around the seals to fill the vacuum which would otherwise be there. These are good qualities of a decent rifle scope to seek out.