What Riflescope Should I Get?
By Chuck Hawks
The title of this article reflects one of the most common questions fielded by gun writers. My more detailed article "Telescopic and Red Dot Sights," found on the Scopes and Sport Optics page, defines the terms used in this article and provides more in depth information about telescopic sights. This little piece is intended to provide succinct answers to the title question.
I think it makes sense to approach riflescope selection based on intended use. For example, if you are hunting in thick brush or deep woods, your anticipated shots will be relatively short, limited by how far you can see. This applies regardless of the caliber of your rifle; whether you are carrying a .30 Carbine or a .300 Magnum, you can't shoot farther than you can see. Conversely, if you hunt open country where you can see animals (and be seen by them) at long distances, longer range shots can reasonably be anticipated. The first requirement is to choose a scope that fits your anticipated needs.
Short Range Riflescopes
If you hunt in areas where the average shot is about 100 yards or less, a riflescope in the 2x to 2.5x range is ideal. A fixed power scope will serve nicely. If you choose a variable power model, make sure it can be set to no more than 2.5x and keep it there. The 1-4x variables work well for short to medium range hunting.
The same scopes are a good choice for dangerous game rifles. Dangerous game animals are large and typically shot between 50 and 150 yards. Higher magnification is not required for accurate shot placement and the limited field of view that accompanies high magnification slows target acquisition and can get you killed in the event of a charge.
Medium Range and General Purpose Riflescopes
Where average shots run 100-200 yards, a 4x fixed power scope will do all that needs to be done. Among variable power models, 2-7x, 2.8-8x and 3-9x models are all popular choices.
I particularly like 2-7x32mm and 2.5-8x36mm models, as they provide all of the magnification necessary for 300+ yard shots, while offering a wide field of view at the low magnification setting. They can usually be mounted in low rings and are smaller and lighter than the ubiquitous 3-9x40mm scopes and thus have less negative impact on the rifle's handling. All scopes degrade the rifle's handling and carrying qualities and the bigger and heavier a scope is, the worse its affect on your rifle.
Long Range Riflescopes
Those with rifles chambered for long range cartridges, such as the .257 Weatherby, .264 Win. Magnum, .270 Winchester, 7mm Magnums or .300 Magnums, and wish to take full advantage of the 300-350 yard maximum point blank range (MPBR) provided by such cartridges will do well with a fixed 6x riflescope. Among variable magnification models, a 2.5-8x, 3-9x or 3-10x scope is an excellent choice.
4-12x models, formerly reserved for varmint shooting, are now being promoted as long range big game scopes, but it is hard to imagine what advantage they actually provide. Even the smaller species of big game are large targets and 8x to 10x magnification is sufficient for precise bullet placement beyond the MPBR of even the flattest shooting hunting cartridges.
So called "scout scopes" are specialized optics intended to be mounted forward of the receiver. They were originally intended to provide a means of mounting a telescopic sight on top ejecting Winchester lever action rifles. I have used such scopes on my Model 94's since they were first introduced in the 1960's, so I know something about them. Jeff Cooper later promoted the use of such scopes on bolt action carbines that he called "scout rifles." A scout scope is better than no scope at all, so if you hunt with a pre-'64 Winchester Model 94, it is a viable alternative to iron sights.
However, forward scope mounting requires extended eye relief and that results in a much reduced field of view, which slows target acquisition for most shooters. Scout scopes manage to combine the worst of both worlds, low magnification (usually about 2x) and a very small field of view. The argument that a forward mounted scope allows shooting with both eyes open is misleading, since (1) most shooters do not keep the off eye open when looking through a scope and (2) even if you keep both eyes open, the natural tendency is to focus your attention on what you see through the scope. With both eyes open you may theoretically see around the scout scope, but your brain tends to ignore peripheral information, particularly under stress.
If your rifle is drilled and tapped for conventional over the receiver scope mounting, that is the best way to go. Avoid the temptation to experiment with a scout scope unless there is no other alternative. An exception might be when scoping a very hard kicking rifle, where the recoil might drive a conventionally mounted scope back into your eyebrow.
Extended Zoom Range
Marketing departments are always looking for new features to hype sales and increase profits by raising prices. This is what accounts for oversize objective lenses, touted for use in dim light, even though--as we have seen--smaller diameter objectives provide more light than a fully dark adapted human eye can accept. In the same (impractical) category are extended zoom range scopes. If you don't need more field of view than is provided by a 2.5x scope or more magnification than 8x, what is the point of a wider zoom range? All such scopes achieve is to lighten your wallet, while placing more weight and bulk atop your rifle. It is also true that, for any given manufacturing cost, increasing the zoom range lowers the optical quality. A wider zoom range inevitably means more compromise in the optical design of the scope. Zoom ranges around three times (3-9x or 4-12x, for example) have proven about optimum for both optical design and use in the field.
Objective Lens Diameter
Since the human eye's pupil can only dilate to a maximum opening of about 7mm (and that would be in near total darkness), any scope that provides an exit pupil (light pencil) of 7mm is transmitting as much light as your eye can theoretically use, assuming you have perfect (young) eyes. Middle aged shooters' eyes are usually limited to about 5mm of pupil dilation and the light transmitted by a scope with an exit pupil larger than 5mm is therefore wasted. A riflescope's exit pupil is easily calculated by dividing the objective lens diameter by the magnification. For example, a 5x35mm scope has a 7mm exit pupil.
Fixed magnification 2x-3x scopes should be provided with a 20mm objective, which allows a straight 25mm external tube diameter for optimum mounting versatility and rifle balance. This provides (in the case of a 2.5x20mm scope) an 8mm exit pupil (light pencil).
For a fixed 4x scope or a 2-7x zoom, a 32mm objective lens is more than adequate. A 32mm objective provides a 8mm exit pupil at 4x magnification and a 5mm exit pupil at 6.4x.
A 2.5-8x36mm scope provides a generous 7.2mm exit pupil at 5x and a useful 5.1mm exit pupil at 6x. This is excellent brightness!
The popular 3-9x40mm scope has the largest objective required for practically any big game hunting situation, allowing the use of 5.7x for a 7mm exit pupil and 8x for a 5mm exit pupil. Larger objective lenses, such as the 50mm objectives offered as an alternative by most manufacturers, merely add weight and bulk to your rifle (not to mention a higher selling price). Remember, it is the diameter of the scope's exit pupil, not its objective lens, which determines how much light actually reaches your eye.
I prefer simple reticles, since I want to focus on the target and shot placement, not the reticle. Any reticle that involves multiple aiming points or requires calculations does not belong in a big game hunting scope. The original Leupold Duplex reticle is my favorite hunting reticle and a plain (medium) crosshair is another good choice. However, if your preference is for a dot, post or German #4, that's fine. Choose any reticle you can shoot fast and accurately.
Avoid blister-packed economy scopes. Spend as much money as you can afford on your riflescope. In optics, quality rules. I have never heard a shooter complain that his or her scope was "too good." Here are some reputable, widely distributed riflescope brands that offer multiple lines at a variety of price points: Leupold/Redfield, Sightron, Nikon, Weaver, Bushnell and Burris. Anyone should be able to find an appropriate hunting scope from one of these companies.
Copyright 2012 by Chuck Hawks. All rights reserved.