Everything You Need To Know About Rifle Optics Part 1
12 Important Things You Should Know About Rifle Optics - Part 1
Now that numerous law enforcement agencies are allowing their officers to use rifles, it has become for law enforcement operations to have rifle optics.
1. Kinds of Optics
There are two major categories of firearm optics for sale: reflector (reflex) sights and telescopic sights.
Telescopic sights, which are commonly called "scopes," are a type of sight that is used for magnification purposes in order to make a target seem closer for a shooter, which makes it easier for a precision shot to be taken by the shooter.
"Reflex" sights or reflector sights are optics where the image of the target is not magnified. It features one point of reference like a red dot to provide very vast sight acquisition. This type of optic is very useful to use in a close-quarter combat situation, particularly against moving targets and multiple targets. They also can be used by skilled shooters at ranges over 200 years. One shooter who provided information for this article said he is able to hit a 12-inch plate at 200 yards around 75% of the time with a short-barreled 5.56mm rifle with an Aimpoint T1 that has 3x magnification.
"Reflex" is short for the word reflector. Nearly all reflex sights make use of an internal light source like an LED and mirror to reflect the reticle image back to the shooter's eye. However, holographic sights that were initially marketed by EoTech (L-3 EcoTech now) use lasers for projecting one point of aim on a film that is enclosed inside of the optic. Holographic sights don't use reflection but are usually classified as a kind of reflex sigh single they provide one point of reference for providing quick target acquisition to the shooter.
2. What these Numbers Mean
The way that telescopic sights get categorized is based on their tube size and magnification. It is expressed in a series of number. For instance with the Leupold VX*R Patrol 1.25-4x20mm product name, the 1.25-4 refers to the fact that variable magnification is offered by the scope from 1.25 power up to 4 power, and 20mm refers to the objective lens diameter.
3. Optical Terminology
Whenever firearms optics are discussed, there is a bunch of terms that get thrown around. The following are a couple of terms you should be familiar with.
Exit Pupil When a scope is held at arm's length and then pointed at a bright surface like a wall that is in a well-lit area, you will be able to see the exit pupil. This a circle of light. This light is how much illumination enters into the scope. The bigger the exit pupil is, the bright the image will appear in the scope.
Eye Relief The distance between the eyepiece and shooter's eye from where a shooter is able to see the whole image inside of the magnified scope without there being "vignetting," which is a dark eclipse effect. As the magnification is changed eye relief changes on a variable power scope. Tim O'Connor, Leupold consumer services manager, says that shooter needs to get the eye relief matched to the cheek weld. He says they get lots of calls from individuals whose scope is mounted incorrectly for their eye relief. They tell him there is something wrong with the scope. However, the problem isn't the scope, it is the mounting position.
Field of View Refers to the width you can see through your scope and measured at specific distances in meters or feet. A smaller field of view has a higher magnification.
4. Minute of Angle (MOA)
This is a unit of measurement that equals 1/60th of a degree. Therefore, one MOA is around 100 yards. When it comes to shooting, it means the impact of all the shots in a circle with a 1-inch diameter. With a 2 MOA sight, you can place all your shots at 100 yards inside of a 2-inch circle, and at 200 yards with a 4-inch circle, and so forth.
5. Kinds of Reticles
This is the aiming indicator that is inside of the optic. It might be the center point of a horseshoe, a ring, a red dot, an old-fashioned crosshair or other types of shapes.
Usually, a reticle on close-quarter-combat (CQB) sight is measured in MOA. Snipers use scopes for making for long distance or very precise shots have reticles that measure in milliradians (1/1000 of a radian). Math and mil-dot reticles can be used by trained shooters to calculate wind drift, bullet drop, size of the target, and range of the target in order to make shots at very long distances.
On CQB optics, a red dot-style reticle is a lot more common. On an Aimpoint red dot sight, the reticle size is commonly 4 MOA or 2 MOA. It is better to have a larger reticle for quick acquisition of a target within a close-quarter situation. They are also easier to see when both eyes are open. It is better to have a smaller reticle for precision from a distance.
Recticles are frequently illuminated by fiber optics, battery-powered LEDs or radioactive decay from amount tritium amounts.
6. Sight in Your Optics
Firearms instructor Rob Garrett, who writes for some of the leading firearms magazines in the nation and was a former law enforcement officer of 37 years, recommends that officers zero or sight in on the patrol rifle optics at 200 yards and at 50 yards, since a majority of law enforcement rifle shots, including even those taken by SWAT team precision shooter are taken from under 100 yards. Garrett says that with a 50/200 yard zero, that the point of impact as it relates to point aim isn't more than 8 inches from zero up to 200 yards. This keeps shots well within your center mass.
It is crucial that when zeroing the optic that the actual mechanics be performed properly and officers need to know what needs to be done. Patrol rifle course instructors say it isn't unusual to see officers carrying rifles that are fitted with optics that haven't been properly zeroed or haven't been zeroed at all.