What is a Rifle Scope?
A rifle scope is a sighting system that sits on top of a rifle to help the shooter aim in on their target. It consists of lenses, a tube and, some sort of reticle (cross hair, dot, etc.) inside.
The tube is mounted externally on the rifle’s barrel or receiver with scope mounts and scope rings.
Rifle scopes are often magnified to make targets appear closer. The target appearing closer helps the shooter land more precise shots.
Rifle scopes generally improve a shooter’s efforts in gaining the true accuracy potential of their rifle by adding some magnification to the sight picture, but not all scopes are magnified.
These are usually used in tactical situations and are good for close quarters combat. This type of optic helps the shooter acquire a target much faster and the reticle is usually an illuminated dot, though there are other reticles as well.
This type of optic doesn’t necessarily require eye relief and can be placed anywhere on the receiver. As a general rule of thumb, going as far forward on the receiver as possible is considered a best practice because it allows you to use both eyes.
Fixed power scopes:
Fixed power scopes have the magnification set by the manufacturer and cannot be changed.
Variable power scopes:
On variable power scopes the magnification of the sight picture can be adjusted according to the distance of view needed by the user by simply turning the power ring.
A rifle scope marked as 4x-12x, is power or magnification, which means it will magnify an object from 4 times larger than you could see with the naked eye and by turning the power ring it will adjust up to 12 times larger than you could see with the naked eye.
The objective lens is the lens in the front of the scope, the larger the diameter the more light gathering ability it has.
The larger the objective lens, higher scope rings are needed to allow your lens to clear the rifle barrel. A typical scope description of 4-12X44, the objective lens is 44mm.
Check out the review for the above pictured Leupold Scope, by clicking that link.
Adjustable objective lens:
The adjustable objective lens has the ability to correct parallax at given yardages to keep the scope on target zero for all yardages regardless of the shooter’s eye alignment in the scope.
Parallax is a condition that occurs when the image of the target is not focused precisely by misalignment of the shooter’s eye on the reticle plane.
This condition accounts for more enlarging of rifle group sizes than anything else.
Parallax is visible as an apparent movement between the crosshairs and the target when a shooter moves their head and changes eye alignment in the scope.
The higher the magnification the more visible this is. A good, high power rifle scope will have an adjustable objective lens to correct parallax at all yardages.
Exit pupil diameter:
The exit pupil diameter is the shaft of light exiting the scope toward the shooter’s eye, this is expressed in millimeter measurement.
Field of view:
Field of view is the measure of how much area you can see through your scope at 100 yards, generally, the higher the magnification, the less the field of view.
With a field of view of 40 feet, simply means at 100 yards with a target in the center of the scope you will be able to see 20 feet to the left and 20 feet to the right of the target centered in the reticle crosshairs.
Eye relief indicates the distance between your eye and the scope, which allows you to achieve the scope’s entire field of view. An eye relief of three inches simply means that your eye is 3 inches from the scope and you’re able to see the entire field of view.
With an incorrect eye relief you will not be able to see the entire sight picture through your scope, and there will be a black ring around it indicating that you need to adjust your eye relief.
Scope Rings and Mounts:
Most scopes do not come with a method of attaching to your rifle, though some do. There is a lot to know regarding the proper selection of scope rings and mounts, to include the type of mount, the size of the rings, and how to mount them properly.
Check out this guide from our good friends at Gun University on how to find the right scope rings for your setup.
Recommended Rifle Scopes:
This Nikon riflescope is one of the best buys for the money, and can be found at under $160.
Here is a Vortex Strike Eagle that’s a great option in the $300 price range.
This is an excellent option that comes in under $500.
This Burris scope is a great option in the $800 price range.
And, when you want to look through some of the finest glass, ever, you’ll pay upwards of $2,000.
Ever wonder how to mount your rifle scope?