How to Choose a Rifle Scope

What Shooters Need To Know

Just mounting a rifle scope and using it is about as basic as you're going to get when the time comes to shoot with glass sights. The following shows how to gain an understanding of exactly what you're dealing with when you turn to a scope sight versus the standard iron sight setup on a firearm.

understanding rifle scopes

Scope quality depends on the basic tube housing and glass quality. As I have indicated in several previous reviews, scopes are placed in degrees of quality based largely on price. More is better in almost all cases. However, buyer beware here and stay with solid brand names when turning loose some high dollar deals on scope glass.

First of all, scope main tube housings are usually made from aluminum, and the grade or quality of the material will dictate the level of field time you're going to get from that optical system.

types of scopes

Look for aircraft grade aluminum steel tube designs, but stay way from pot metal junk or plastic. Yes, plastic is even found in lens systems. Lens glass is judged by light-gathering quality and the limit of distortion produced by the lens in high, strong or poor light conditions.

When you buy a $1000 rifle scope, the glass is generally quite good. When you buy a $3000 scope, that lens glass had better be awesome when you view anything through it. Long-range shooters require this higher level of glass, but shooting your 22 rimfire in the back forty will most certainly not need this level of quality. 

Brand name, price, and where you buy the product will dictate how much quality you're getting for your money. If the price is unavailable, the deal is most likely not what you think it might be.

When selecting magnification power settings, I mean the level of magnification between 1 power and 25 or so, think about your needs as a shooter. Sometimes buying more power than is necessary only adds cost, and complicates your shooting experience. 

looking through a scope

For example, if you're a deer hunter in the upper mid-western USA and you're always in wooded areas, using a rifle scope much above 7X is not necessary. However, if you're hunting in the American west, you're going to need a bit more, and a 3X 9X power setting scope is just about a minimum.

Turning to the lens size at the objective (front end of the scope), the size will dictate the amount of light that the scope can pull in. In general, 40 mm objectives are average and will do most jobs well, but the 50 mm and even 55 mm are best when used under very low light conditions. 

Outside the USA and for most of Europe, hunting is done in the almost dark or very early in the morning. I have shot boar in Russia under these conditions and we used 50 mm optics. In about 90% of your shooting situations, the 40 mm objective will do the deed just fine.

Reticle selection is much like choosing power settings and objective size. This choice depends on where you're going to be shooting and at what. When I hunted for years along the border between Minnesota and Canada, I encountered heavy brush country, high grass swamps, and black willow. Shooting was close and fast on whitetail. 

When I hunted in this country, I always selected a rifle with a weaver steel tube low 4 pour setting that made use of a thick black single line in the reticle. A thin horizontal line was added to correct for tilt when zeroing.

Today, living in the western half of the country, I shoot on high power settings with a very fine crosshair. This is to allow me to see the target around my center.

Today there are dozens of reticle designs and it is impossible to cover them all. Buyers must view many of them and decide which reticle will do the job. Longer-range shooters will need MOA hash marks or MRAD settings, as well as the correct gun-sight. 

scope magnification explained

OMG range rifle scope with MOA hash marks for elevation and windage, required for elevation adjustment on shots beyond 500 yards

Russian military sights, for example, all carry a simple gap system in the reticle for ranging objects. When applied to the Dragunov sniper rifle, it is a series of gaps engraved in the reticle that measure the height of an average man at different ranges. In others, it is the average size of a Russian tank.

looking through a scope

Dragunov, author's own industry test rifle, one of the most feared rifles in the world, 7.62X54 “Russian 30-06”. The scope is simple and deadly effective (its reticle is the key to its success).

Focal Plane

Rifle scopes are offered in a first FFP, or second SFF, and each has its own characteristics. A first focal plane scope will allow the size of the crosshair to increase with the amount of magnification used. Target size increases as does the sight itself. Good for very long-range shooting. 

Focal plane

The second focal plane system leaves the crosshairs at the same size, but increases the target size with increased power (magnification) settings. This is often preferred by hunters, and most scope builders use this system. If you're shooting competition longer range hunting on wide open plains or in mountain country, the first focal plane is almost a must have.

Parallax Issues

Parallax control is an issue taken up by using a parallax control knob at the front bell or on the left side of the turret house. In some smaller rifle scopes, parallax is pre-set and adjusted for average-range shooting. In others that deal with longer ranges, parallax settings are by manual control and correspond with range marks on the turret knob. 

Set the knob for 400 yards and the parallax level on the optical system is corrected for that distance.

Lens Coatings

When you see the manufacturer mention lens coating, they are talking about treating the glass for surface protection, haze and glare reduction, or even more complicated elements involved with keeping the sight picture clear and crisp at all ranges. The better the scope, the better the coating types do in terms of offering a better sight image through the lens.

Field of view

When we discuss field of view applied to a rifle scope sight, we are referring to the distance (measured) around the target itself. The more fiweld your shooter sees, the better control he or she has if the target moves or runs. In most cases, the lower poer scopes have a greater field of view. 

As the power settings increase, the level of field decreases, even in very high grade and high priced rifle scopes. The exact amount of data with any new scope will be indicated by the measured figures at each range the scope is capable of generating magnification power. 

This is why snipers and hunters like to work with 6X 10X power glass, and it gives the shooter an edge on running targets with a larger field of view.

Light Transmission

When we discuss lens coating, pricing of scopes, and glass quality, we talk about light transmission to a large degree. Lacking strong light, the scope becomes worthless in many situations. Good transmission allows the hunter or shooter to see into dark, shaded areas that with budget glass will show up as a black area lacking any form whatsoever. 

Best Scopes for AR 15 with great light transmission will seem to be as clear as a well cut diamond, with very bright white light clarity and super sharp images in the crosshairs.

rifle scope basics

1000-yard coyote target, 300 Win Mag, good rifles and glass get the job done

In terms of bullet drop at longer ranges and MOA graduations, the better grade longer-range scopes will retain MOA dots that correspond to 1 inch at 100 yards and an additional inch for every successive 100 yards. (For example, 5 inches per dot at 500 yards, and 10 inches at 1000 yards.) 

When the DOPE (data of previous engagement) has been calculated, each corresponding dot will increase the level of hold-over by simply moving to that dot. If the data calls for a 20-inch hold-over at 500 yards, for example, the shooter will move to the fourth MOA dot on the vertical line toward the 6 o'clock position on the scope reticle. 

Once you are familiar with the system, it will be like riding a bike. You will never forget.

weapon scope

If you consider getting into longer-range shooting and buying better equipment, I would suggest that you also attend a long-range class or school, if possible. Many local gun ranges offer this training, and some run several-day camps and teach from a classroom setting to the hands-on live firing range. 

For more information, Google long-range shooting schools.

Want to know How To Use a Rifle Scope? check out our guide.

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