Many people correlate the numbers associated with scopes to the distance a particular scope should be used. While the numbers often associated with scopes are, to some degree, an indication of how well the scope performs at a distance, it is by no means a hard and fast guide to the distances to which a scope can reach.
A riflescope, at its heart, is a telescope with a few other features specific to shooting. The goal of any telescopic optical instrument is to bring the image of things far away closer to our eye, making them easier to see. Telescopic sights are not necessarily limited by the distance but by the amount they can enlarge the image downrange while maintaining focus, clarity, and color.
Many variables affect a riflescopes ability to do its intended job. This article focuses on those factors that affect the size of the image seen by the shooter. For this article, we are assuming that the riflescope is of good quality. You must understand the terms we use to discuss riflescopes.
Riflescopes – The Nuts and Bolts
Riflescopes are, on the surface, simple affairs. A riflescope often hides its complexities inside a sleek housing and behind crystal clear glass. Before we launch into discovering how to relate a riflescopes description to the proper distance expectations, we need to have at least a bit of understanding about how a riflescope works.
From the Outside Looking In
Outside, most riflescopes look very much the same. Most optical telescopic sights have a set of standard features that are recognizable despite the manufacturer. These common parts include:
- The tube – The tube is the main body of the riflescope and usually houses the erector.
- Objective lens – the objective lens is housed in the bell of the scope and faces the target. The bell or objective lens is usually much larger than the scope tube.
- Eyepiece – At the other end of the scope tube, closest to the shooter, is the eyepiece. The eyepiece may be fixed or have an adjustment to aid in focusing the reticle against the target.
- Elevation and windage turrets – Without a way to align the reticle with the rifle, a riflescope is useless. The knobs attached to the scope tube allow the reticle to be adjusted up and down and right and left to align the reticle with the bullet’s impact point.
For the most part, these are the primary parts of any riflescope. Some rifle scopes may have more adjustments and may include variable magnification, but every optical riflescope will have these four parts.
Understanding a Riflescopes Description
Most manufacturers will give their riflescopes catchy names to attract buyers. Names such as Eagle, Raptor, Freedom, and Match Pro evoke the sorts of activities we want to associate with a riflescope. However, performance and possibilities are better described by the standard numbering system used by most scope manufacturers.
Standard Fixed Magnification Optical Scopes
Standard fixed magnification optical riflescopes are the mainstay of the riflescope industry. These fixed magnification scopes are typically the most basic of riflescopes and tend to be the simplest to operate and the least expensive to purchase.
In the world of riflescopes, these scopes tend to be designated by a single number followed by another number. The first number indicated the riflescope’s magnification, and the second number describes the size of the objective lens in millimeters. So, a scope with a magnification of 10 and an objective lens measuring 30 millimeters in diameter would be designated as a 10×30 riflescope.
Magnification – How Big Can It Get?
The magnification identified with your scope represents how much larger the image of your target appears in the scope than in real life. For example, a bullseye that appears to be one-tenth of an inch tall at one hundred yards with the naked eye will appear to be one inch tall through a 10x rifle scope.
Theoretically, there is no real limit to the amount of magnification that can be applied through a riflescope. There are practical limitations to the size of the lenses, the length and diameter of the scope, and the weight of the scope on the rifle.
Variable Power Scopes – Adding More to the Description
There are many hunting and target shooting situations where having multiple magnifications in a single scope would be advantageous. Scope manufacturers, willing to please their customers, introduced the variable-magnification, or telescopic, riflescope many years ago.
Most of these variable magnification scopes feature a magnification ring at the rear of the scope that can be turned to increase or decrease the amount of magnification. These scopes are designated by the addition of the third set of numbers to the description.
Thus, a riflescope that will move between magnifications four and twelve is designated as 4-12×30. These numbers indicate variable magnification between four times and twelve times with a thirty-millimeter objective lens.
Variable magnification makes a riflescope much more adaptable to situations and requirements for many hunters. With the advent of bullets and calibers at home shooting out to 1000 yards as they are in the 200-yard range, this ability to match magnification to distance is extremely attractive.
But How Do I Know What Magnification to Use When Shooting?
In a word, you use what works best for you. Understanding the advantages and disadvantages of higher magnifications can help you make some of these decisions. No grid or guide sets out a specific distance for a specific magnification. The factors in play with the shot are the more important determinators of what magnification to use for any shot.
When More is Better
There are times when having the most magnification possible is the best choice. Some of these situations and conditions may be a signal that your riflescope magnification may not quite be enough for the job.
- You can’t quite see enough of the target – If you are on the outside of your magnification range, you still can’t see an aiming point on your target. If you are shooting a .22 LR at a ground squirrel, two or four magnifications at one-hundred-fifty yards may not be enough depending on your eyesight. On the other hand, twelve X magnification on a standard whitetail deer at the same one-hundred-fifty yards may be too much. Sure, you can see the individual hairs on the deer, but can you see what is around and behind the deer. What if another hunter is obscured because the image of the deer is so big?
- The light is low – It may be late in the day or just overcast. The ambient light, even in your scope, just isn’t producing a clear, sharp image. A bit more magnification might do the trick and sharpen that image enough to get a clear and precise image. However, past a certain point, increased magnification dims the view of the target.
- Your target is not moving – Stationary targets work great at higher magnifications. Many competitive shooters use targets with much higher magnifications than any hunter would ever use. With high magnification, your field of view narrows so much that if a target suddenly moves out of the frame, you may never locate that target again.
- You don’t have to move much – If you are moving during a hunt consistently, the cost of high power scopes is the extra weight and bulk they require. The mechanisms and lenses in high-power scoped are heavy. High magnification scopes are great where bench shooting is the norm, and the longest move you make with the scope is from your vehicle to the shooting bench.
The higher the magnification of your scope, the more weight and bulk it requires. The mechanisms inside the scope to manage the magnification focus, parallax correction, and other adjustments become more and more delicate. Cost is always a factor in high quality, higher magnification scopes.
The 3-9X40 Rifle Scope – Popular and Useable
According to many industries experts, the most popular variable magnification riflescope is the 3-9X40. Almost every riflescope manufacturer in the marketplace makes a version of this riflescope. There are many reasons for this popularity.
A Look at the Ranges and Targets
Let’s consider hunting. The most popular game animal in the United States is the white-tailed or mule deer. These species are widely hunted in almost every state in the United States. Several calibers of deer rifles are commonly used for hunting these deer. The average white-tailed and mule deer stand about twenty-one to forty-two inches at the shoulder.
Hunting deer typically occurs at ranges from 75 to 175 yards and is often done from stationary stands placed close to feeders or food plots. Consider a deer that is 24 inches tall at the shoulder 10 yards from a deer stand. To most shooters, this deer appears to be about 2.4” tall.
Now, put a four-power magnification scope on that rifle and that 2.4-inch target now appears to be almost 10 inches tall. That is a much easier target to make and, with the reticle in the scope, a much easier shot to take.
Versatility and Reliability
A good 3-9×40 variable magnification scope is perhaps the most versatile scope available. The 3 to 9 magnification puts this scope into the range of many of the most popular rifle cartridges in the United States. Many long-range precision shooters and hunters chasing some of the biggest game on the North American Continent opt for the venerable 3-9×40 riflescope.
At ranges out to 1,000 yards, a high-quality 3-9×40 riflescope will perform admirably under most conditions. Beyond 1,000 yards, everyone but the most experienced shooters will probably need to move up in objective lens size to gather more light or increase the upper magnification range to a 10X or 12X scope to gain the additional image size.
A Comparison – Ranges, Rifles, and Magnification
To get a better idea of how range affects your choice of magnification in a riflescope, you should consider several factors. These factors and how they affect both hunting and competitive target shooting.
- Target Size and Distance – There is a considerable difference in shooting at a bull elk and a prairie dog. Some prairie dog hunters pride themselves on making shots in excess of 500 yards on such a small quick target using special calibers and bullet loads. Many elk hunters routinely approach shoots in the 1000 yard range across mountain valleys to get a trophy shot. Both shooters may need the features found in much higher magnification scopes, such as an 8-24×50 riflescope. The larger objective lens of this size scope gathers light more efficiently, and the higher magnifications have their obvious advantages.
- Rifle caliber factors – Your choice of rifle caliber has as much to do with your scope selection as the type of shooting you expect to perform. One of the most popular rifles in the United States is the Ruger 10/22 .22 LR. These rifles are popular for target shooting, plinking, and small varmint hunting. We all know the .22 LR is best at ranges between 75 and 200 yards. There is no reason to mount a high magnification scope with a huge objective lens on such a rifle. Match your rifle scopes magnification to the capabilities of your rifle.
- Types of Shooting – Making shots offhand on a target that may be moving requires a scope with just enough magnification to accurately see your target. Too much magnification makes it hard to track moving targets. Too much magnification also magnifies jitter and vibration in the scope. Learn to match your magnification to the needs of your shooting type.
Like most other aspects of hunting and competitive shooting, the situation’s needs often dictate the equipment. It is great to count the tines on a big buck deer, but you must consider other problems such magnification may create trying to make the shot.
A Quick Guide to Riflescope Sizes and Distances
To close, as a quick reference, we offer these suggestions about the most appropriate scope sizes for different distances. For these recommendations, certain assumptions are underlying our decisions. These underlying assumptions include:
- Most hunters typically use a medium-caliber hunting rifle in the United States for hunting game animals.
- Average shooter capabilities with normal eyesight
- Factory loaded ammunition
With these understandings, these are our recommendations for scope sizes.
|1 – 4 X Magnification||5 – 8 X Magnification||9 – 12 X Magnification|
|Target shooting up to 100 yardsBenchrest shooting up to 150 yardsSmall varmint hunting up to 100 yards||Ranges up to 200 yardsMedium-sized North American game animals such as white-tailed deerBenchrest shooting out to 300 – 500 yards||Target shooting up to 500 yardsHunting almost any game animal in North AmericaBenchrest shooting out to 750 yards|
Finding Your Best Fit
There are so many variables that affect the choice of a riflescope that it is almost impossible to make hard and fast rules. Many of these factors are personal, and many are dictated by the type of shooting, the caliber of the rifle, and the size of the target.
You can apply general rules to selecting a scope for the ranges you shoot, but, in the end, you must find the best scope fit for your requirements and expectations. Common sense goes a long way in making good decisions. Good luck and good shooting.